CHEMISTRY 20
Notes and problemsUnit 4: Acids and Bases
pH = -log [H3O+(aq)]
pOH = -log [OH-(aq)]
pH + pOH = 14
Prepared by Daniel VeraartCIS Abu Dhabi
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Chemistry 20Day 29
Date: ________________________ Name: __________________________
Empirical Definitions of Acids and Bases:
ACIDS
Names for acids refer to aqueous solutions of the pure substance. For example: HCl(g) is called hydrogen chloride while the aqueous HCl(aq) is hydrochloric acid.
The most common acids are given on P.11 of your booklet. There are two types of acids:
1. Strong acid: The first 6 acids of the table: HCl , HBr , HI, H2SO4, HNO3 and HClO4.2. Weak acids: All the other acids of the table. (CH3COOH , HOOCCOOH , …).
To find if an acid is strong or weak, we can check the conductivity of the solution
- If the solution conducts electricity greatly Strong acid- If the solution conducts electricity slightly Weak acid
BASES: The common bases are positive ions bonded to hydroxide ions (OH-). When bases dissolve in water, they dissociate to produce a metallic ion and the hydroxide ion.
Properties of acids and bases
Properties Acids BasesTaste
Color with litmus
Reaction with metals
PH
Neutralize what?
Conductivity
Color with phenolphtalein
Color with bromothymol blue
Feel
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Common Acids and bases:ACIDS
Products Acids in the product
Acetic acid = CH3COOH
Salicylic acid = C6H4(OH)COOH
Carbonic acid = H2CO3
Phosphoric acid = H3PO4
Citric acid = C6H8O7
Ascorbic acid = C6H8O6
BASESProducts Bases in the product
Sodium hydroxide = NaOH
Magnesium hydroxide = Mg(OH)2
Ammonia = NH3
The pH
Chemistry 203
The pH Scale
Chemists have developed a scale that classifies how acidic or basic substances are. This pH scale classifies substances from 0 to 14.
• Acids have a pH of less than 7.• Bases have a pH greater than 7.• Substances that fall in the middle of the scale are neutral.
As you get closer to 0, the substances get more acidic. As you move toward 14 on the scale, the substances get more basic.
Note: A change of 1 in the pH scale represent a change of 10X the concentration.
Example: A pH of 4 is 10X more acidic than a ph of 5A pH of 12 is 10X more basic than a pH of 11
Homework 29
Date: ________________________ Name: __________________________
Exercices1. Classify the following solutions as acids, bases or neutral.
a) bleach, pH = 12.4: _______ b) urine, pH = 6.0 : ________ c) coffee, pH = 5.0: _______ d) sugar water, pH = 7.0 : _______ e) egg white, pH = 7.8 : ________
2. Which of the following substance would turn litmus red?
A. Water B. Ammonia C. Pop D. Bleach
3. Mr. Clean probably has a pH
A. of 7 B. of 0 C. lower than 7 D. greater than 7
4. The pH of blood is 7.4 and the pH of urine is 5.4. Which of the following statement is true?
A. Blood is more basic than urine B. Blood is more acidic than urineC. Both blood and urine would turn red litmus blue D. Both blood and urine are examples of acids.
5. A teacher gives you an unknown substance, how could you identify if this substance is acidic, basic or neutral?
A. By tasting itB. By testing if the substance is corrosiveC. By putting the substance in water and testing it with an universal indicatorD. By looking at the substance, acids are colourless solutions while bases are white solids
6. Which of the following properties does not apply to a base?
A. pH greater than 7 B. React with magnesiumC. Turn red litmus blue D. Can be neutralised with vinegar
7. When a pool manager tested the water with blue litmus, it turned pink. In order to neutralize the water in the pool, the pool manager should add
A. hydrochloric acid diluted (acid) B. sodium carbonate diluted (base)C. distilled water (neutral) D. chlorine (disinfectant)
8. After using an oven cleaner, some people rinse the oven with a dilute solution of vinegar. What is the purpose of the vinegar rinse?
A. To change the smell of the oven B. To clean what the oven cleaner wasn’t able to cleanC. To produce a salt D. To neutralize the oven cleaner that remains in the oven
9. Which of the following properties does not apply to an acid?
A. pH greater than 7 B. Sour tasteC. Turn blue litmus red D. Can be neutralised with baking soda
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10. Hydrogen is produced when magnesium reacts with
A. CH3OH(aq) B. C2H5OH(aq) C. CH3COOH(aq) D. C6H12O6(aq)
11. An acidic solution
A. does not conduct electricity B. reacts with zincC. neutralizes CH3COOH(aq) D. taste bitter
12. Which of the following substance would turn litmus blue?
A. Water B. Hydrochloric acid C. Lemon juice D. Bleach
Use the following information to answer the next two questions
13. The basic solution is
A. Solution 1 B. Solution 2 C. Solution 3 D. Solution 4
14. The student made an error in its observation for
A. Solution 1 B. Solution 2 C. Solution 3 D. Solution 4
15. True or False. Justify the false statements.
A. _________: Soap is an example of base.
B. _________: Lemon juice tastes bitter. C. _________: A solution of vinegar has a pH of approximately 0.
D. _________: A solution of baking soda taste bitter because it’s pH is lower than 7.
E. _________: The solution we find in a car battery would react with magnesium.
F. ________: Aspirin is an acid and would then turn bromothymol blue to yellow.
G. _______: Litmus paper can help you finding the exact pH a solution.
H. ________: Many household cleaners would react with magnesium.
I. ________: A pH of 9 is more acidic than a pH of 5.
J ________: A solution with a pH of 5.2 is considered very acidic.
K. ________ : Concentrated acids and bases are corrosive.
L. _______: A solution of vinegar is a strong acid.
M. _______: A solution with a pH of 4 is more acidic than a solution with a pH of 2.
Launch Lab5
A student records the following observation when testing 4 solutions:
Reaction with magnesium Bromothymol blueSolution 1 No reaction BlueSolution 2 Gas produced YellowSolution 3 No reaction GreenSolution 4 No reaction Yellow
The colour of your breath
Introduction: Bromothymol blue is an acid-base indicator used to test if a substance is neutral, basic or acidic. In this lab, we will try to find out if your breath is neutral, basic or acidic.
Materials:
- Bromothymol blue - NaOH(aq) - Straw -Erlenmayer- Stopwatch
Procedure:
1. Add 100 mL of distilled water in the Erlenmayer flask. Add five drops of bromothymol blue. Record the color.
2. Add drops of NaOH(aq), swirling the solution after each addition, until the solution turns blue (it might be after one drop).
3. Start the stopwatch. Using the straw, blow into the solution (pick the student with the worst breath) until the solution changes color.
4. Record how long it takes for a color change to occur. 5. Repeat steps 2, but hold your breath for 30-45 s before step 3.Record time to change color.
Analysis:
1. Make a table of observations.2. Based on your prior knowledge, what type of substance was produced when you blew into
the solution. Explain your answer.3. How did holding your breath for 30-45 seconds affect your observations, if at all?
Chemistry 206
Day 34
Date: ________________________ Name: __________________________
How can we measure the pH?
We can measure the pH of a solution using a pH meter or a universal indicator.
pH meter: Electronic device used to measured with precision the pH of a solution.
Universal indicator: A universal indicator is a mixture of several indicators that turns a different colour for each number on the pH scale. It is usually sold as a roll of paper and is cheaper than a pH meter.
Lab #2Finding the pH of acids and bases
Problem: Using a pH meter and a universal indicator to find the pH of 10 solutions.
Design: Test all solutions for the pH with the pH-meter and the universal indicator. Record observations in the table below.
Solution pH with pH-meter pH with universal indicatorTide
Cream of tartarAspirin
Baking sodaAntacidVinegar
Drain cleanerRubbing alcohol
Ammonia
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Lab #3Purple cabbage as a Universal indicator
Problem: Using purple cabbage as a universal indicator
Design: Prepare 11 solutions with pH between 2 to 12 and add cabbage solution to them. Keep a sample of each solution. Test the 4 unknown solutions for the pH. Record observations in the tables below.
PH Color of solution23456789101112
Solution Color of solution pH of the solution1234
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Chemistry 20Day 30
Date: ________________________ Name: __________________________
Acids and Bases in Solution
Svante Arrhenius (1859-1927) was one of pioneer in the study of acids and bases. He won a Nobel prize in 1913 for Chemistry for his work. Arrhenius’s explanation of the properties of acids and bases is the Arrhenius’s theory of acids and bases.
Arrhenius Theory of Acids and Bases
An Arrhenius acid is a substance that ionizes to form hydrogen ion (H+) concentration in aqueous solution.
Ex. : HCl(g) HCl(aq) H+(aq) + Cl-
(aq)
An Arrhenius base is a substance that dissociates to produce hydroxide ion (OH-) in aqueous solution.
Ex. : NaOH(s) NaOH(aq) Na+(aq) + OH-
(aq)
The hydrogen ion is really only a proton (with no electron). If such a particle comes near polar water molecules, it is likely to bond strongly to it and become what we call a hydronium ion.
H+(aq) + H2O(l) H3O+
(aq)
Using the Arrhenius theory, we could infer that acids must contain a source of H+(aq) and bases must contain a source of OH-(aq).
Examples
Classify the following solutions as acidic, basic, or neutral.
a) HNO3(aq) : ____________ b) Ca(OH)2(aq) : ____________
c) HBr(aq) : ____________ d) LiOH(aq) : ____________
e) NaCO3(aq) : ____________ f) NH3(aq) : ____________
Does the Arrhenius theory successfully predict acidic or basic properties in all cases?
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New and improved Arrenius’ definitionsEvidence from the examples above indicates the limited ability of Arrhenius's theory to predict acidic or basic properties of a substance in aqueous solution. Only four substances followed the definition: HNO3 (aq), HBr (aq), Ca(OH)2 (aq) and LiOH(aq)
The other substances did not follow that definition; therefore, the Arrhenius’s definitions of acids and base needed to be revised.
A modified Arrhenius theory
An Arrhenius acid reacts with water to produce hydronium ions H3O+(aq) in aqueous solutions.
Examples: HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)
CH3COOH(aq) + H2O(l) H3O+(aq) + CH3COO-
(aq)
An Arrhenius base dissociates or reacts with water to produce hydroxide ions OH-(aq) in aqueous solutions.
Examples: NaOH(s) Na+(aq) + OH-
(aq)
Example #1: Ammonia is a base because of the reaction of ammonia with water that produces the hydroxide ion.
NH3(aq) + H2O(l) NH4+
(aq) + OH-(aq)
Example #2: Sodium carbonate in water produce a basic solution:
First, sodium carbonate dissociate: Na2CO3(s) 2 Na+(aq) + CO3
2-(aq)
Second, the carbonate ion reacts with water: CO32-
(aq)+ H2O(l) OH-(aq) + HCO3
-(aq)
Example #3: Sodium hydrogen sulfate in water produces an acidic solution:
First, sodium hydrogen sulfate dissociate: NaHSO4(s) Na+(aq) + HSO4
-(aq)
Second, the hydrolysis: HSO4-(aq)+ H2O(l) H3O+
(aq) + SO42-
(aq)
Example #4: Carbon dioxyde in water produces an acidic solution:
First, carbon dioxyde reacts with water: CO2(s) + H2O(l) H2CO3(aq)
Second: H2CO3(aq)+ H2O(l) H3O+(aq) + HCO3
-(aq)
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Exercises:
1. Explain why the following substances are considered as acids or bases (According to Arrhenius)
a) Na3PO4(s), produces a solution with a pH = 11 when dissolved in water.
b) NH4Cl(s) produces a very weak acidic solution when dissolved in water.
c) Baking soda produces a very weak basic solution when dissolved in water.
d) Nitric acid is a very acidic solution.
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Chemistry 20Homework 30
Date: ________________________ Name: __________________________
Exercises:
1. Write a chemical equation to show how the following acids would react in water, according to the modified Arrhenius theory of acids and bases.
a) HCl(aq)
b) NH4Cl(aq)
c) NaHSO4(aq)
d) H2SO3(aq)
2. Write a chemical equation to show how the following bases would dissociate or react in water, according to the modified Arrhenius theory of acids and bases.
a) Ca(OH)2(aq)
c) Na3PO4(s)
b) NaS2 (aq)
c) LiOH(aq)
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Chemistry 20Day 31
Date: ________________________ Name: __________________________
Strong and Weak Acids and Bases
According to the modified Arrhenius theory of acids and bases, all acids produce hydronium ions in water and all bases produce hydroxide ions in water. Not all acids, however ionize to the same degree.
Strong acid
Strong acid: An acid that ionizes nearly 100% in water.
For example: HCl(g) + H2O(l) H3O+(aq) + Cl-(aq) (100% reaction)
Weak acid
Weak acid: An acid that reacts very little in water. Only a small percentage of the acid molecule form ions in water.
For example: CH3COOH(g) + H2O(l) H3O+(aq) + CH3COO-(aq) (1% reaction)
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Notice the double arrow-headed equilibrium arrow in the equation above. This arrow indicates that the solution is in equilibrium.
The acid molecules are constantly reacting with water to form the ions and the ions are constantly reacting to form the acid molecules and water.
Strong base
Strong base: A strong base dissociate completely into ions in water. All oxides and hydroxides of alkali metals and Earth alkali metals are strong bases.
For example: NaOH(s) Na+(aq) + OH-
(aq) (100% reaction)
Weak base
Weak base: A weak base is a substance that reacts very little in water to produce a very small amount of hydroxide ions.
For example: NH3(g) + H2O(l) NH4+
(aq) + OH-(aq) (1% reaction)
Only about 1% of ammonia molecules react in water to produce OH-(aq). In a 0.10 mol/L solution of ammonia,
the concentration of OH-(aq) is only about 0.0010 mol/L.
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Chemistry 20Homework 31
Date: ________________________ Name: __________________________
Exercises:
1. Classify the following as neutral ionic, molecular, strong acid, weak acid, strong base or weak base.
a) C6H5COOH: ______________ b) HF : ______________
c) NH3 : _____________ d) Na2CO3 : ________________
e) KOH : ___________________ f) Mg(OH)2 : _________________
g) NaCl : ____________________ h) Na3PO4 : __________________
i) HCl: ____________________ j) NH4Cl(aq) : __________________
k) NaHSO4(aq) : ________________ l) HNO3(aq) : __________________
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Chemistry 20Day 32
Date: ________________________ Name: __________________________
Communicating concentration: pH and pOH
In 1909 a chemist, Soren Sorenson, developed a simplified system for referring to the degree of acidity of a solution. He used the term pH for power of hydrogen. pH refers to the concentration of hydronium ions in solution.
[H3O+(aq)] ranges from about 10.0 mol/L down to 1.0 x 10-15 mol/L in common aqueous solutions. A range on
the order of a quadrillion to one can only be expressed by using logarithm. Expressed as a numerical value without units, the pH can be calculated using the following formula:
pH = - ( log10 [H3O+(aq)] )
If you know the pH of a solution, you can calculate the [H3O+(aq)] using the following formula:
[H3O+(aq)] = 10-pH
Although pH is used in most applications, in some applications it may be convenient to describe hydroxide ion concentration in a similar way. The definition of pOH follows the same format and the same rule as for pH
pOH = - ( log10[OH-(aq)] )
[OH-(aq)] = 10-pOH
The mathematics of logarithms allows us to express a simple relationship between pH and pOH
pH + pOH = 14
Summary : Formulas to be memorized
pH = - ( log10 [H3O+(aq)] )
[H3O+(aq)] = 10-pH
pOH = - ( log10[OH-(aq)] )
[OH-(aq)] = 10-pOH
pH + pOH = 14
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Examples :
1. Calculate the pH of a sample of acid rain in which [H3O+(aq)] = 1.2 x 10-4 mol/L
2. Find [H3O+(aq)] in a bottle of pop that has a pH of 2.1
3. Find the pH of a 0.0060 mol/L KOH solution
4. Find [OH-(aq)] in solution with a pH of 12.9
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6. A student dissolves 1.55 g of NaOH in 500 mL of water. What is the pH of the solution?
7. A student want to prepare a 1.00 L of a solution with a pH =1.4 . What volume of concentrated (12.4 mol/L) hydrochloric acid must be used?
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Chemistry 20Homework 32
Name: ____________________________ Date: __________________________
Exercises
1. Find the pH of the following solutions
a) Solution with [H3O+(aq)] = 1.00 x 10-6 mol/L : pH = _________
b) Solution with [H3O+(aq)] = 1.50 x 10-2 mol/L : pH = _________
c) Solution with [OH-(aq)] = 1.00 x 10-6 mol/L : pH = _________
d) Solution with [H3O+(aq)] = 0.00150 mol/L : pH = _________
2. Find the pH of lime juice if [H3O+(aq)] = 0.0120 mol/L? _____________
3. Find the pH of blood if [OH-(aq)] = 2.6 x 10-7 mol/L? ______________
4. Find the pH of a solution made of 1.00 g of KOH in 1.00 L of water? Show your work.
5. Classify the following substances from the least acidic to the most acidic.
Solution A : pH = 6 Solution B : [H3O+(aq) ] = 1.0 x 10-4 mol/L
Solution C : [OH-(aq)] = 1 x 10-13 mol/L Solution D : pH 9
________ ________ ________ _________ Least Most
7. What mass of potassium hydroxide is contained in 500 mL of solution that has a pH of 11.5? Show your work.
8. A student make a solution in which [H3O+(aq)] = 1.0 x 10-3 mol/L. This solution would
A. be green in bromothymol blue B. be pink in phenolphtaleinC. turn litmus red D. have a pOH of 3
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9. Hydrogen is produced when magnesium reacts with
A. CH3OH(aq) B. C2H5OH(aq) C. CH3COOH(aq) D. C6H12O6(aq)
10. A student wants to clean the spill of a car battery. Which household substance should be used?
A. Water B. Vinegar C. Lemon juice D. Baking soda
11. Which of the following substance is a base
A. HOOCCOOH(aq) B. Ba(OH)2 (aq) C. CH3OH(aq) D. NH4+
(aq)
12. What is the pH of a 0.0010 mol/L LiOH (aq) solution?
A. 3.0 B. 7.0 C. 10 D. 11
13. An acidic solution
A. does not conduct electricity B. reacts with zincC. neutralizes CH3COOH(aq) D. taste bitter
14. A 0.0300 mol/L HCl(aq) has a pH of
A. 2.48 B. 2.00 C. 1.52 D. 0.480
15. If the pH of a solution is 8.0 ,
A. [H3O+(aq)] > [OH-
(aq)] B. [OH-(aq)] > 1.0 x 10-7 mol/L
C. [OH-(aq)] = 1.0 x 10-8 mol/L D. [H3O+
(aq)] = 8,0 mol/L
16. A student find the pH of a fruit juice to be 2.4 . The [H3O+(aq)] of this juice is
A. 4.0 x 10-3 mol/L B. 2.5 x 10-8 mol/L C. 3.8 x 10-1 mol/L D. 2.5 x 10-18 mol/L
17. A sodium hydrogen carbonate solution has a pH of 8.0 , [OH-(aq)] is
A. 1.0 x 10-13 mol/L B. 1.0 x 10-8 mol/L C. 1.0 x 10-6 mol/L D. 1.0 x 10-5 mol/L
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Chemistry 20Day 33
Date: ________________________ Name: __________________________
Acid-Base Indicators
Acid-Base IndicatorsAcid-base indicators are substances, which have one color in acidic solutions and another color in basic solutions.The color change for each indicator is related to specific pH values
List of indicators : Data booklet P. 10
Indicators can be use to find:
1. the approximate pH of a solution. 2. the equivalence point for the neutralization reaction.
Example #1: Complete the following table : Find the color of the following indicators .
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pH of solutions
BromothymolBlue
Methylorange Phenolphtalein Cresol red Thymol blue
1
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pH of solutions
BromothymolBlue
Methylorange Phenolphtalein Cresol red Thymol blue
2
3
4
5
6
7
8
9
10
11
12
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Example #2: A solution is yellow with methylorange and red with methyl red. What is the approximate pH of this
solution?
Example #3:
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Colors of an acid with different indicators.
Test tubes Indicator Color 1 Orange IV Yellow 2 Methyl orange Yellow 3 Bromocresol green Blue 4 Methyl red Orange 5 Bromothymol blue Yellow
The approximate pH of the solution is between ______________________
Example #4: Four unknown solutions labelled I, II, III and IV were tested and these data were obtained:
Indicator I II III IV Thymol blue green yellow green orange Methyl orange yellow orange yellow red
Thymolphtalein colorless colorless blue colorless
The acidic solution(s) is/are _________________
Lab #6pH of solutions
Problem : Find the pH of 4 solutions using only indicators.
Design: Find the approximate pH using the following indicators:
Acidic range: Bromophenol blue – Methyl red Neutral range: Bromothymol blue Basic range: Phenol red – Phenolphtalein.
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Compare with the real pH given by your teacher.
Questions
1. Make a table of observation.
Lab #7Prepare solutions with specific pH
Problem : To prepare an acidic and a basic solution with a specific pH from a potassium hydroxide and a 0.6 mol/L HCl solution.
Materials : - Scale - Volumetric flask - Solid KOH 0.6 mol/L HCl
Design:
Calculate the mass of solid potassium hydroxide needed to make a solution with a specific pH given by your teacher. Add the solid to a known volume of water. Mix and record the pH with a pH-meter.
pH = __________ Volume = _________
Calculate the volume of 0.6 mol/L HCl needed to make a solution with a specific pH given by your teacher. Add the acid to a known volume of water. Mix and record the pH with a pH-meter.
pH = __________ Volume = _________
Questions
1. Calculate the mass of base needed. 2. Calculate the volume of 0.6 mol/L HCl needed. 3. Make a table of observations. 4. Calculate the percent of error for each solution.
Chemistry 20Homework 33
Name: _____________________ Date: _________________
2. If we add a base to a solution,
A. [H3O+(aq)] decreases and pH increases B. [H3O+
(aq)] decreases and pH decreasesC. [H3O+
(aq)] increases and pH increases D. [H3O+(aq)] increases and pH decreases
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3. Phenolptalein would be pink in which of the following solutions?
A. [OH-(aq)] = 1.0 x 10-3 mol/L B. [H3O+
(aq)] = 1.0 x 10-4 mol/LC. [H3O+
(aq)] = 1.0 x 10-5 mol/L D. [OH-(aq)] = 1.0 x 10-11 mol/L
4. If a solution easily conducts electricity and turns blue litmus red, the solution is probably
A. HNO 3(aq) B. NaCl (aq) C. Ba(OH) 2(aq) D. CH3COOH (aq)
Colors of an acid with different indicators.Test tubes Indicator Color 1 Orange IV Yellow 2 Methyl orange Yellow 3 Bromocresol green Blue 4 Methyl red Orange 5 Bromothymol blue Yellow
5. The approximate pH of the solution is between
A. 3.0 and 4.0 B. 4.0 and 5.0 C. 5.0 and 6.0 D. 6.0 and 7.0
6. A student make a solution in which [H3O+(aq)] = 1.0 x 10-3 mol/L. This solution would
A. be green in bromothymol blue B. be pink in phenolphtaleinC. turn litmus red D. have a pH of 4
7. The indicator bromothymol blue would be green in a solution with
A. pH = 1 B. pH = 7 C. pH = 10 D. pH = 14
Use the following information to answer the following questionColour of an unknown solution with different indicators
Methyl violet is Blue Phenol Red is Red Indigo carmine is Blue Phenolphtalein is colorless
8. The approximate pH of the solution is _______
9. Four unknown solutions were tested with different indicators.27
Solution Observations 1 Methyl orange was orange 2 Thymolphtalein and indigo carmine were blue 3 Litmus was blue and phenolphtalein was colourless 4 Bromocresol green was blue and bromothymol blue was yellow
The solutions from the most basic to the most acidic are respectively:
, , , ______
Chemistry 20Day 39
Date: _____________________ Name: _________________________
Chemical analysis by titration
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Titration is a common experimental design in chemistry used to determine the concentration of a substance in solution.
Titration involves the carefully measured and controlled addition of a solution from a buret into a measured volume of a sample solution until the reaction is judged to be completed.
Buret: A buret is a precisely marked glass cylinder with a stopcock at one end. It measures a volume of reacting solution.The solution in the buret known as the titrant is added to the sample until the reaction is complete.
An indicator is used in all acid-base titration. The color change of the indicator indicates the end of the reaction.
Some Definitions
Titration: It’s a progressive transfer of a solution from a buret into a measured volume of a sample solution. It is used to determine the concentration of a solution.
Endpoint: The completion of the reaction is indicated by a sudden color change of an indicator. This is referred as the endpoint of the titration.
Equivalence point: The measured quantity of titrant added when the endpoint occurs is called the equivalence point.
Standard solution: Solution used in the buret. Standard solutions are solutions with precisely known concentrations.
A titration analysis should involve several trials, using different samples of the unknown solution to improve the reliability of the answer. A typical requirement is to repeat measurements until three trial results within 0.2 mL (and then take the average).
Titration is a good example of a chemical technology that is reliable, economical and simple to use.
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Lab #11Titration Analysis of Vinegar
Problem: What is the concentration of acetic acid (CH3COOH(aq)) in a sample of vinegar? You will determine the amount of acetic acid in white vinegar titration with a solution of NaOH whose concentration is known. The indicator will be phenolphthalein
Materials: Buret Strirrer Erlen-mayerGraduated cylinder Waste beaker ScaleSodium hydroxideVinegar
Procedure:
1. Prepare 100 mL of a standard 1.00 mol/L solution of NaOH(aq). 2. Fill the buret with the standard solution.3. Add 25 mL of vinegar to the Erlen-mayer. Add 10 drops of phenolphthalein.4. Start the titration until the indicator changes color.5. The titration is repeated until three consistent results are obtained (within 0.2 mL)
If you read the label on the vinegar bottle, the concentration of acetic acid is given inpercent (by weight) and not in molarity. But since we have calculated the mass of aceticacid, we can calculate the mass percent if we know the mass of vinegar we used in thetitration. Vinegar is mainly water (with a little acetic acid in it), so we'll assume that thevinegar has the same density as pure water, that is, 1.0 mL of acetic acid has themass of 1.0 grams.
Mass percent = 100% x (mass of acetic acid/mass of vinegar)
Observations:
Titration #1 Titration #2 Titration #3 Titration #4(if needed)
Volume of Vinegar
Molarity of NaOH
Initial Buret Reading
Final Buret Reading
Volume of NaOH Added
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Questions
1. What mass of sodium hydroxide is required to make 100 mL of the standard solution.
2. Calculate using stoichiometry the concentration of acetic acid in the sample.
3. Calculate your percent of error.
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Calculations page
32
Chemistry 20Day 34
Date: _____________________ Name: _________________________
Acid Base Stoichiometry An acid-base titration problem is essentially a stoichiometric problem between an acid and a base. An acid-base titration is a complete chemical reaction between an acid and a base. The products of an acid-base titration are always the same: Water and a salt.
The four steps of stoichiometric calculations
1. Write a balanced chemical equation for the reaction and determine the two substances involved in the reaction, the given and the unknown will often be the acid and the base.
2. Find the number of moles of the given substance using the following formulas:
n = m (If a mass is given) n = C . V (If a solution is given) M 3. Find the molar ratio between the given and unknown substances using the chemical
equation. This will give you the number of moles of the unknown substance.
Number of moles = Unknown Given
4. Answer the question by using the number of moles found in step #3 and one of the following formulas:
m = n.M or C = n / V or V = n / C or V = nRT/P
Examples:
1. A student titrates 25.0 mL of NaOH solution with 0.100 mol/L HCl until the endpoint was reached. These are the result recorded by the student:
Initial buret reading: 0.600 mLFinal buret reading: 16.3 mL
Find the concentration of NaOH in this solution.
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2. During a titration, 5.00 g of NaOH solid are neutralized with 150 mL of H2SO4(aq) . What was the concentration of the acid?
3. 50.0 mL of a Mg(OH)2(aq) solution is titrated with 22.4 mL of a 0.100 mol/L HCl until the endpoint is reached. Find the concentration of Mg(OH)2(aq) .
4. 1.59 g of sodium carbonate solid was added to an Erlenmayer flask and titrated with diluted HCl(aq). The titration evidence collected is shown below
Trial 1 2 3 4Final buret reading 13.3 26.0 38.8 13.4Initial buret reading 0.2 13.3 26.0 0.6
The concentration of the diluted HCl(aq) Is ___________ mo/L.
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Chemistry 20Homework 34
Name: ____________________________ Date: __________________________
Exercises
1. 10.0 mL of 0.400 mol/L KOH(aq) were used to titrate 40.0 mL of HCl(aq). Find the concentration of the HCl(aq).
2. Lise needed 2.23 g of NaOH(s) to neutralize a 50.0 mL sample of sulfuric acid. What was the molar concentration of the acid?
3. If 22.4 mL of a 0.100 mol/L HBr(aq) solution are required to neutralize a 0.200 mol/L Ca(OH)2(aq)
solution, what volume of base was used?
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4. A student wants to find the concentration of the vinegar from the cafeteria. The student decides to titrate 10.0 mL of vinegar with a 0.0100 mol/L Ca(OH)2(aq). The following data were collected :
Trial Initial reading (mL) Final reading (mL)1 0.4 15.42 15.4 28.43 28.4 31.24 31.2 44.3
What is the concentration of vinegar?
5. If 2.00 g of an unknown acid (HA) neutralizes completely 45.0 mL of a 0.347 mol/L NaOH (aq)
solution, find the molar mass of the acid.
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Chemistry 20Day 35
Date: _____________________ Name: _________________________
Chemical analysis by titration
Titration is a common experimental design in chemistry used to determine the concentration of a substance in solution.
Titration involves the carefully measured and controlled addition of a solution from a buret into a measured volume of a sample solution until the reaction is judged to be completed.
Buret: A buret is a precisely marked glass cylinder with a stopcock at one end. It measures a volume of reacting solution.The solution in the buret known as the titrant is added to the sample until the reaction is complete.
An indicator is used in all acid-base titration. The color change of the indicator indicates the end of the reaction.
Some Definitions
Titration: It’s a progressive transfer of a solution from a buret into a measured volume of a sample solution. It is used to determine the concentration of a solution.
Endpoint: The completion of the reaction is indicated by a sudden color change of an indicator. This is referred as the endpoint of the titration.
Equivalence point: The measured quantity of titrant added when the endpoint occurs is called the equivalence point.
Standard solution: Solution used in the buret. Standard solutions are solutions with precisely known concentrations.
A titration analysis should involve several trials, using different samples of the unknown solution to improve the reliability of the answer. A typical requirement is to repeat measurements until three trial results within 0.2 mL (and then take the average).
Titration is a good example of a chemical technology that is reliable, economical and simple to use.
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Interpreting pH curves
For many acid-base reactions the appearance of the products resembles that of the reactants, so you cannot directly observe the progress of a reaction. Also, acids cannot easily be distinguished from bases except by measuring pH.
The pH values and changes provide important information about the nature of acids and bases, the properties of conjugate acid-base pairs and indicators, and the stoichiometric relationships in acid-base reactions. A graph showing the continuous change of pH during an acid-base reaction is called a pH or titration curve for the reaction.
What is a titration curve?
Titration curve : It’s a graph of pH vs volume of substance added. This graph shows the fast change in the pH when the equivalence point is reached.
There are two types of titration curve:
1. Titration curve for the titration of a strong acid with a strong base.2. Titration curve for the titration of a strong base with a strong acid
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Two types of titration curves
1. Titration curve for the titration of a strong acid with a strong base:
pH
Volume of base added
Characteristics of the curve: ____________________________________________
____________________________________________
2. Titration curve for the titration of a strong base with a strong acid:
pH
Volume of acid added
Characteristics of the curve: ____________________________________________
____________________________________________
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Examples:1. It takes 83 mL of a 0.45 mol/L sodium hydroxide solution to neutralize 235 mL of hydrochloric acid
solution. What is the concentration of the hydrochloric acid solution?
pH+
Volume of acid./base added
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Chemistry 20Homework 35
Name: ____________________________ Date: __________________________
Exercises
1. It takes 38 mL of 0.75 M NaOH solution to completely neutralize 155 mL of a sulfuricacid solution (H2SO4). What is the concentration of the H2SO4 solution? Do not forget to complete a titration curve.
pH+
Volume of acid./base added
2. You are titrating an acid into a base to determine the concentration of the base. Theendpoint of the neutralization is reached but the stopcock on the buret sticks slightlyand allows a few more drops of acid to fall into the solution. How will this affect yourcalculations for the concentration of the base?
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3. It takes 12.5 mL of a 0.30 M HCl solution to neutralize 285 mL of NaOH solution. Whatis the concentration of the NaOH solution? Do not forget to complete a titration curve.
pH+
Volume of acid./base added
4. Lulu Labwrecker carefully pipets 25.0 mL of 0.525 M NaOH into a test tube. She placesthe test tube into a small beaker to keep it from spilling and then pipets 75.0 mL of0.355 M HCl into another test tube. When Lulu reaches to put this test tube of acid intothe beaker along with test tube of base she accidentally knocks the test tubes togetherhard enough to break them and their respective contents combine in the bottom of thebeaker. Is the solution formed from the contents of the two test tubes acidic or basic?What is the pH of the resulting solution?
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PROJECT ON STOICHIOMETRYCreate a power point presentation with the following parts
- Description of the chosen reaction and problem- Description of one of the chemical involved in the reaction (Properties-
Production-Usage- 3 Interesting facts)- Stoechiometric calculations- Material + Procedure + pictures (or video) of the experiment.- Table of observations, Percent of error, References
4 3 2 1
StoichiometricCalculations
-Good chemical equation-Good answer
-All scientific convention- All 4 steps
3 out of 4 points covered and correct
2 out of 4 covered and correct
1 out of 4 covered and correct
Other parts of the project
X2
All 5 parts are includedDetails are correct
4 out of 5 parts covered and correct
3 out of 5 parts covered and correct
2 out of 5 parts covered and correct
PresentationQuality
-Pictures (video) present-Animation
-Grammar/Spelling-Overall quality
3 out of 4 points covered
2 out of 4 points covered
1 out of 4 points covered
Description of chemical
- Physical properties are included
- Usage is included- Production is included
- Facts are included
3 out of 4 points covered
2 out of 4 points covered
1 out of 4 points covered
TOTAL = /20
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Examples of reactions for the stoichiometry project
Single replacement:
Example: Mg(s) + HCl(aq)
Zn(s) + H2SO4(aq)
Cu(s) + AgNO3(aq)
Neutralization:
Example: Vinegar + Baking soda Gas produced
H2SO4(aq) + KOH(aq)
Aspirin or other commercial acids with KOH(aq)
Precipitation:
Example: Na2CO3(aq) + CaCl2(aq)
KI(aq) + Pb(NO3)2(aq)
Combustion:
Example: CH3OH(aq) + O2(g)
C25H52(aq) + O2(g)
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Chem 20 Project Working sheets
Part A: Research
1. Write a balanced equation of your reaction.
___________________________________________________________________
2. Choose one of the chemicals involved in the reaction and answer the following questions.
a) Chemical chosen: __________________________
b) Find the following physical properties: Phase at room temperature: __________Melting point: _________Boiling point: _________Density: _________
c) A short description of what this chemical is used for.
___________________________________________________________________________
___________________________________________________________________________
d) A short description of how this chemical is produced.
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
e) List 3 interesting facts about the chemical.
__________________________________________________________________________
__________________________________________________________________________
__________________________________________________________________________
f) Which references did you used to find the information about the chemical?
______________________________________________________________________
3. State your problem. (Reaction and quantity f reactants used)?
_______________________________________________________________
_______________________________________________________________
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4. Calculate the amount of products that should be produced (stochiometric calculations).
Step #1: ________________________________________________________________
Step #2: ________________________________________________________________
Step #3: ________________________________________________________________
Step #4: ________________________________________________________________
Part B: Experiment
1. Make a list of material.
2. Write a short procedure.
3. Make a table of observation.
4. Calculate the percent of error by using the following formula:
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Chemistry 20Day 42
Date: _____________________ Name: ________________________
Introduction to organic chemistryThe nature of Organic Chemistry has changed greatly since 1828. Before that time the scientific philosophy known as "Vitalism" maintained that Organic Chemistry was the chemistry of living systems. It maintained that Organic Compounds could only be produced within living matter while Inorganic compounds were synthesized from non-living matter. Even the word "organic" comes from the same root as the word "organism" or "organ". However people like Professor Wohler beginning in 1828 determined that it was indeed possible to synthesize organic compounds from those compounds that were considered inorganic. One of the first organic compounds synthesized from basically inorganic compounds was the compound Urea which is a metabolic product of urine. Since then many millions of Organic compounds have been synthesized. Organic Chemistry has developed into a branch of Chemistry that focuses upon the carbon containing compounds.
Definitions
Organic chemistry: Study of the molecular compounds of carbon.
Organic compounds: Organic compounds are those based on the element carbon. They contain carbon and hydrogen and have a carbon-hydrogen bond.
Exceptions: Compounds that contains the ions : CO32- , CN- , HCO3
- are not organic compounds
Inorganic compounds : All the other compounds
Chemists usually represent organic compounds using a condensed structural diagram showing only the carbon-carbon bonds.
Example: Butane (C4H10) is represented: CH3 - CH2 - CH2 - CH3
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There are actually two different ways of representing the molecule of C4H10.
1. As butane: CH3 - CH2 - CH2 - CH3
2. As methylpropane CH3 - CH2 - CH3
| CH3
These substances have the same molecular formula C4H10 , but two different structures; these two substances are know as isomers of C4H10 .
Isomers
Isomers: Substances with the same molecular formula but different structures.
Examples: C4H10 has 2 isomers C5H12 has 3 isomersC10H22 has 75 isomers C20H42 has 366 319 isomers
Examples: using the molecular model, draw the condensed structural diagram of all the isomers of the molecules below.
a) C2H3Cl3 b) C5H12
b) C2H2Br2O d) C3H6O2
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Functional groups in Organic Compounds
Organic Chemistry is the largest branch and fastest growing branch of Chemistry. Generally Organic Chemistry is manageable by classifying organic compounds into "families".
Each family consists of compounds that have a chemically active center of the molecule called the family's "functional group". All members of a particular family have similar Chemistry because their functional group is the center of Chemical activity.
Functional groups
Functional groups are characteristics arrangements of atoms within a molecule.
Chemists divide organic compounds into families, classifying them according to functional groups.
Functional groups are largely responsible for properties of the compound.
The properties of ethanol are largely determined by the presence of the –OH group of atoms which is known as the hydroxyl group.
The properties of organic acids are largely determined by the presence of the –COOH group of atoms which is known as the carboxyl group.
Classifying Organic CompoundsOrganic chemists divide carbon compounds into families, classifying them according to functional groups.
These groups help to explain many of the chemical properties of organic compounds.
The table on the next page lists families of organic compounds, each of which you will study in this unit.
In the general formulaR represents any chain of carbon and hydrogen toms.
X represents a halogen atom.
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Family name General formula Example
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Chemistry 20Homework #42
Name: ____________________________ Date: __________________________
Exercises
1. Match the following compounds to the families listed below. You can use the same family more than once.
1 = Acids 2 = Alcohols 3 = Aldehydes 4 = Alkane 5 = Alkene 6 = Alkyne 7 = Alkyl halide 8 = Esters9 = ketone
O ||a) CH3 - CH2OH - CH3 : _____ b) CH3 - CH - CH2 – C - CH3 : ____
c) CH3 - CH - CH2- CH=O : _____ d) CH3 – CH2 - COO -CH2 - CH2 - CH3 : _____ | CH3
e) CH3 -CH2 -CH2-CH2 – COOH : _____ f) CHC-CH2-CH3 : _____
CH3 CH3
| |g) CH3-CH-CH-CH-CH3 : _____ h) CH3-CH2-C-CH=CH2 : _____ | | | CH3 CH3 C2H5 F | i) CH3 - CH2 - CH2 - C - CH2 - CH2 - CH3 : _____ j) CH3COOCH3 : _____
| CH2 - CH3
k) CH3CHO : _________ l) HCOOH : _______ m) CH3OH : ______
n) CH3-CH2OH-CH2-CH3 : ______ o) CH2-CH3 -CH-CH3 | : _____
CH2-CH3
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2. The compound with the formula C4H10O could be classified as
A. ketone B. alcohol C. ester D. aldehyde
3. The compound with the formula C4H8 could be classified as
A. Alkane B. Alkene C. Alkyne D. Alcohol
4. The compound with the formula C4H8O2 could be classified as
A. ketone B. alcohol C. ester D. aldehyde
5. Which of the following compound would have a triple bond
A. C3H8 B. C3H6 C. C3H4 D. C3H14
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Chemistry 20Day 43
Date: ____________________ Name: _________________________
Hydrocarbons
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Important information
Coal, crude oil, oil sands, heavy oil and natural gas are the primary sources of hydrocarbons. Petroleum is a complex mixture of hundreds of thousands of compounds. The differences in boiling points of the compounds making up petroleum enable the separation of these compounds in a process called fractional distillation.Refining is the technology that includes separating complex mixtures into purified components.
A fractional distillation tower
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F ractional distillation petroleum
Boiling point range of fraction (°C)
Carbon atoms per molecule
Fraction Applications
Below 30 1 to 5 Gases Fuels for cooking and heating homes
30 to 90 5 to 6 Ether Dry cleaning, solvents, camping fuel
30 to 200 5 to 12 Gasoline Automotive gasoline175 to 275 12 to 16 Kerosene Diesel, jet engines250 to 375 15 to 18 Fuel oil Furnace oilOver 350 16 to 22 Heavy gas oil Lubricating oilsOver 400 18 and up Grease Lubricating greasesOver 450 20 and up Waxes Candles,…Over 500 26 and up Residues Asphalt and tar
Alkanes
The IUPAC(international Union of Physics and Chemistry) rules will be used for naming all organic compounds. In this system, the following stems for naming organic compounds containing up to 12 carbons in a straight chain are used.
# of carbons Stem name Branch name Branch Structure1 Meth Methyl - CH3
2 Eth Ethyl - C2H5 or -CH2-CH3
3 Prop Propyl - C3H7 or -CH2-CH2-CH3
4 But Butyl - C4H9 or -CH2-CH2-CH2-CH3
5 Pent Pentyl - C5H11 6 Hex X X7 Hept X X8 Oct X X9 Non X X
10 Dec X X11 Unodec X X12 Dedec X X
Definition
Hydrocarbons whose structural formula indicates only single carbon to carbon bonds are called alkanes.
Alkanes have a general formula of CnH2n+2
All carbon-carbon bonds in alkanes are single bonds; this means the maximum number of hydrogen atoms are bonded to each carbon, and the molecule is said to be saturated.
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Notes
The simplest member of the alkane series is methane CH4(g), which is the main constituent of the natural gas sold for home heating.
Each member of the alkane family have the suffix “ane” .
Example: CH4(g) : methane C2H6(g) : ethane C3H8(g) : propaneC4H10(g) : butane C5H12(l) : pentane C6H14(l) : hexaneC7H16(g) : heptane C8H18(l) : octane C9H20(l) : nonaneC10H22(l) : decane C11H24(l) : unodecane
Rules to name alkanes
1. Name the longest continuous chain of carbon atoms in the molecule by naming the stem for the appropriate number of carbon atoms plus the suffix “ane”.
2. For branched chain alkanes, number the carbon atoms of the longest continuous chain starting at the end closest to the branching.
3. Locate the branch by the number of the carbon atom to which it is attached on the main chain.
4. Name the branch. The position and name of the alkyl branches are given first in the overall name. The location of each group is indicated by the lowest possible numbers.
5. If more than one of the same alkyl groups are present as branches, use di – tri- tetra
Examples:
1. Name the following compounds.
CH3
| CH3-CH-CH2-CH3 : _________________________________________________________
CH2 - CH3
| CH3-CH2-C-CH2 -CH2 -CH3 : ____________________________________________________ | CH3
CH3
| CH3-CH-CH2-CH-CH2 -CH -CH3 : ____________________________________________ | | CH3 CH2 - CH3
CH3 CH2 -CH3
| | CH3-CH2-CH-CH2-CH-CH -CH2 -CH3 : ________________________________________________
| CH2-CH2-CH3
CH2-CH3 |
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CH3-CH-CH2-CH-CH2-CH3 : ________________________________________________ |
CH2 -CH3
2. Write the condensed structural diagram for the following compounds.
a) 2-methyl butane b) 3,3-diethyl pentane c) 2,3,4-trimethyl 3,5-diethyl heptane
Shortcut
Many shortcuts can be used to simplify larger molecules. The two simple shortcut used in chem 20 are:
1. Use the molecular formula for some parts of the molecule.
CH2-CH3 C2H5
| |Example: CH3-CH-CH- CH2- CH2- CH3 becomes CH3-CH- CH-C3H7
| | CH2-CH3 C2H5
2. Use of brackets within the chain when the same group is repeated.
Example: CH3-CH2-CH2- CH2-CH3 becomes CH3-(CH2)3-CH3
Examples:
1. Name the following compounds.
CH3- CH-C2H5 : _________________________________________________________
CH3-(CH2)4 -CH3 : ____________________________________________________
CH3- CH-(CH2)3 - CH3 : ____________________________________________ | C2H5
2. Write the structural formula of the following compound. Use as many shortcuts as you can.
3,4-diethyl 8,8-dimethyl nonane
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Chemistry 20Homework # 43
Date: ____________________ Name: _________________________
1. Name each of the following compounds.
a) CH3-CH2-CH-CH2-CH3 b) CH3-CH2- CH-CH3
| | CH3 CH2-CH3
_____________________________ _________________________________
CH3 C2H5
| |c) CH3-CH-CH-CH-CH3 d) CH3-CH2-C-CH2-CH3
| | | CH3 CH3 C2H5
_____________________________ _________________________________
CH3 C2H5 CH3 CH3 CH3
| | | | | e) CH3-CH-CH2-C–(CH2)3-CH3 f) CH - C - CH | | | |
C3H7 CH3 CH3 CH3
_____________________________ _________________________________
g) C2H5- CH-CH2-CH-CH2-CH3 h) CH3-CH-CH3
| | | CH3 C2H5 C3H7
_____________________________ _________________________________
C2H5 CH3
| | i) CH3-CH2-CH2-C-CH2-CH-CH3 j) CH3-CH2-CH-(CH2)3-CH3
| | C3H7 CH3
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_____________________________ _________________________________
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g) CH3- CH2 – CH - (CH2)3 – CH - C2H5
| CH3
__________________________________________________________
2. Draw the condensed structural diagram for the following compounds.
a) 3-ethyl hexane b) 2,4-dimethyl heptane
c) 3,4-diethyl-3-methyl hexane d) 2-methyl butane
e) 2,2,3,3 tetramethyl pentane f) 3,4-dimethyl-3-ethyl octane
3. Draw the structural diagram and name 4 isomers of C6H14
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Chemistry 20Day 44
Date: ______________________ Name: __________________________
Alkenes and Alkynes
Analysis reveals that hydrocarbons containing double or triple bonds are minor constituents in natural gas and petroleum. However, these compounds are often formed during cracking reactions and are valuable components of gasoline. Hydrocarbons containing double or triple bonds are important in the petrochemical industry because they are starting materials for the manufacture of many derivatives.
Hydrocarbons with carbon-carbon double bonds are member of the alkene family.Hydrocarbons with carbon-carbon triple bonds are member of the alkyne family.
Definitions
Alkenes all contains at least one carbon-carbon double bond and Alkynes all contains at least one carbon-carbon triple bond.Alkenes have a general formula of CnH2n (Two less hydrogen atoms/double bond)Alkynes have a general formula of CnH2n-2 (Four less hydrogen atoms/double bond)
Saturated or unsaturated?
Hydrocarbons that do not contain the maximum number of hydrogen atoms possible are said to be unsaturated with hydrogen. Alkenes and alkynes are, therefore, unsaturated compounds.
Rules to name alkenes and alkynes
1. Name the longest continuous chain of carbon atoms that include the double bond using “ene”. Indicate the position of the double bond with the number of the carbon that precedes the bond.
2. Branches on alkenes molecules are indicated and named as they are on alkane molecules.3. If more than one double bond is present, indicate the positions of all double bonds with numbers
and place a multiplier in the suffix.
To name the alkynes, the same rules apply except that the name of the longest chain that include the triple bond ends with "yne"
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Examples:
a) CH2 = CH - CH3 : _______________________ b) CH2 = CH - CH2 - CH3 : ________________________
c) CH3 - CH = CH - CH3 : ____________________ d) CHCH :
e) CH3-CC-CH3 : _______________________ f) CHC-C-CH2-C-(CH3)2 : ________________________ |
C2H5
g) CH3-CH2-C=CH2 : ________________________ h) CH2=CH-C=CH-CH2-CH3 :______________________ | | CH3 CH2 - CH3
2. Draw the structural formula and name all the isomers of C5H10
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Chemistry 20Homework #44
Name: ____________________________ Date: __________________________
Exercises
1. Name each of the following compounds.
CH3 |
a) CH3-C=CH-C-CH2-CH3 b) CH2=CH-C-(CH2)2-CH3 | | C2H5 C3H7
_____________________________ _________________________________
c) CH2=CH-CH–(CH2)2-CH3 d) CHC-CH2-CH3 | CH = CH2
_____________________________ _________________________________
C4H9 C2H5 | | e) CH2=CH-CH2-CH-C2H5 f) CH3-CH2-CH-CC-CH3
_____________________________ _________________________________
2. Draw the condensed structural diagram for the following compounds.
a) 2,4-dimethyl pent-1-ene b) 3-methyl-4-ethyl hex-2-ene
c) 4,4-diethyl hex-1-yne d) 2-methyl prop-1-ene
e) 3-methyl pent-1,3-diene f) 5-ethyl-4-propyl hept-2-yne
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g) hept-2,5- diene j) 4-propyl oct-4-ene
3. Draw the structural diagram and name 4 isomers of C6H10
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