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CONTENTScontentpage

Contents2

Lab Safety3

Safety Symbols6

Chemistry Laboratory Equipment7

Experiment 1 : Metal, Nonmetal, or Metalloid9

Experiment 2 : properties of ionic compounds13

Experiment 3 : Single Replacement Reactions & Battery Lab16

Experiment 4 : Double Replacement Reactions21

Experiment 5 : pH Measurement and its Applications25

Chemistry Laboratory Safety RulesPersonal Protective Equipment (PPE) and Safe Attire1. Wear chemical safety goggles and a knee length laboratory coat at all times while in the laboratory when anyone is conducting experiments..2. Wear closed shoes at all times while in the laboratory.

3. Wear nitrile gloves when directed to do so by your instructor and/or lab manual.

4. Confine long hair when in the laboratory so that it will not catch on fire or come into contact with chemicals.

Behavioral Rules for Safety5. Do not enter the laboratory until your lab instructor is present.

6. Do not eat, drink, chew gum or smoke in the laboratory at any time. Keep all food and drinks sealed and in your backpack or purse.

7. Consider all chemicals to be hazardous unless instructed otherwise.

8. Do not taste anything in the chemistry laboratory.

9. Smell chemicals carefully and only when instructed to do so. Waft odors towards your nose rather than sniffing directly.

10. Do not use flammable liquids near open flames. Most organic liquids are flammable. Diethyl ether is especially dangerous.

11. When heating substances in a test tube, never point the mouth of the test tube at yourself or at anyone else. It may erupt like a geyser.

12. Do not force glass tubing or thermometers into rubber stoppers. The tubing or thermometer may break and cut you badly. Consult with your laboratory instructor for assistance.

13. Use caution when handling Bunsen burners, hot plates, and glassware or other equipment that has been heated. Burns are the most common laboratory injury so treat all equipment as if it were hot during experiments that involve heating.

14. Work with dangerous or volatile chemicals in a fume hood as directed by your instructor and/or lab manual.

15. Do not perform unauthorized experiments. If you see someone else doing something you think may be dangerous, tell him or her to stop and/or report the incident to your lab instructor. If another student tells you to stop doing something because it is unsafe, stop as directed. Consult your lab instructor if there is a problem or difference of opinion.

Handling Accidents16. Notify your lab instructor immediately if you have an accident, spill, or are injured in any way.17. If chemicals come in contact with your skin or eyes, wash with water for at least 15 minutes.

18. Know where to find and how to use the eyewash stations in the lab. It is not recommended to wear contact lenses in the laboratory since chemicals splashed in the eye may get under the lens therefore be difficult to rinse. If a splash occurs while you are wearing contact lenses, they must be safely removed as quickly as possible.

19. Know where to find and how to use the safety shower in the front of the room.

20. Clean up spilled chemicals immediately. Consult your laboratory instructor if you are not sure what to do.

21. Solid sodium bicarbonate (baking soda) is available in the laboratories in containers located by the sinks. Use this to neutralize acid spills before wiping them up. Similarly, solid citric acid solution is available in containers by the sinks and should be used to neutralize base spills before wiping them up. A saturated solution of sodium bicarbonate is also available by the sinks and can be used to wipe dried acid or base residue off of lab

benches as needed. However, if acid or base spills on your skin, don't waste time looking for these neutralizing substances. Rinse with water immediately for at least 15 minutes.

Proper Waste Disposal

22. Separate waste as follows:

Waste chemicals should be disposed of as directed by your lab instructor. Most chemicals are NOT to be thrown down the sink. Special waste receptacles will be provided for these chemicals. Waste chemicals must be sorted by kind, not just mixed with other, different waste chemicals. Read waste container labels carefully. Notify your instructor when a waste bottle is nearly full. Do not overfill waste bottles.

Broken glass is to be disposed of in the cardboard boxes labeled "Broken Glass Only" located near the doors to the lab. A dustpan and broom are located in each lab to assist you in cleaning up broken glass. Do not put broken glass in the regular trash, and do not put anything except broken glass in the broken glass containers!

Gloves used in lab are to be disposed of in the containers labeled Used Gloves Only located next to the sinks in each lab.

Other trash that is not glass and is not contaminated by hazardous chemicals should be placed in the large waste baskets near the front of the lab room.

Other Information You Should Know

23. The effects of chemical agents used in this course on human pregnancy are unknown. Pregnant women are advised to consult their physician before taking this course.

24. The Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) requires that the Governor revise and publish annually the list of chemicals known to the state to cause cancer or reproductive toxicity. You may be exposed to one or more of these chemicals during this course. See your lab instructor for a list of these chemicals.

25. Material Safety Data Sheets (MSDS) are available for all the chemicals used in this course. These sheets give information about the chemical, physical, and physiological properties of chemical substances. See your instructor for information about accessing these sheets. They can also be found by entering the name of the chemical and MSDS into Google or any other search engine.

26. Each laboratory experiment involves its own specific hazards. Be sure to read your laboratory procedure carefully before arriving for lab, and take note of all safety precautions. You are responsible for the information provided in the laboratory procedure. You must also arrive on time for all laboratory sessions so you will be present to hear the safety information provided by your lab instructor. For the safety of all students in the class, students who arrive late to lab will not be allowed to perform the lab experiment that day.

I, ______________________________ have read and reviewed the list of rules given to me by my teacher relating to the procedures and safety in the laboratory. I agree to behave in a manner that promotes a safe laboratory environment for my classmates and myself. I agree to use chemicals and clean them up in a way that protects my classmates, the environment, and myself. I further agree to follow all other written and verbal instructions given in class.

________________________________________

_______________

Students signature.

SAFETY SYMBOLS

Safety symbols are used to alert you and your students to possible laboratory hazards. SAFETY SYMBOLSDISPOSALBIOLOGICALEXTREME TEMPERATURESHARP OBJECTFUMEELECTRICALIRRITANTCHEMICALTOXICOPEN FLAME

Chemistry Laboratory Common EquipmentBelow are photos and names of common lab equipment you will encounter in Chemistry

Balance (electronic)BeakersBunsen BurnerBuret

Clay TriangleCrucibleCrucible in TriangleCrucible Tongs

Dropper PipetsDropper in actionErlenmeyer FlasksEvaporating Dish

ForcepsFunnelsGogglesGraduated Cylinders

Pinch ClampPipets and BulbsPlastic and Rubber PolicemenRing Clamp & Stand

ScoopulaStirring RodsThermometersTest Tubes in Rack

Test Tube HolderTube & Holder in ActionUtility ClampClamp in action

Wash BottleWatch GlassesWire GauzeCombined for Heating

EXPEREMENT 1 :

Metal, Nonmetal, or MetalloidAims: Explore the physical and chemical properties of eight elements with the goal of classifying them as metals, nonmetals, or metalloids.

Background:

Physical Properties:

properties that can be observed without changing the identity of a substance

Chemical Properties:

properties that are observed while altering the identity of the substance involved

Metals:

elements that are usually silver-gray in color, with the exception of copper and gold

solid at room temperature except mercury, which is a liquid

lustrous or shiny appearance and reflect light when polished

can be bent or hammered flat (malleable

can be drawn into wire

good conductors of heat and electricity

usually show reaction with acids

usually high melting point

Nonmetals:

found to the right of the zigzag line on the periodic table

usually dull in appearance and do not reflect light

many brittle and cannot be hammered into sheets

poor conductors of electricity and heat

show little or no reaction with acids

low melting points

exist as either solids or gas, bromine is an exception, it is a liquid

Metalloids:

found on both sides of the zigzag line on the periodic table except for aluminum

show properties of both metals and nonmetals

are not good conductors of electricity

when mixed with small amounts of other elements the conductivity of metalloids increases

Note: There are many exceptions to the rules for classifying elements.

SAFETY CAUTION

Safety Precautions:

Perform this lab activity in a well-ventilated laboratory. Iodine is toxic by ingestion and inhalation; it is corrosive to the skin, eyes, and the respiratory tract; avoid inhalation of iodine vapors by keeping the iodine bottle covered throughout the lab. Hydrochloric acid solution is corrosive to eyes and skin. Cupric chloride solution is toxic if ingested. Avoid contact of all chemicals with eyes and all body tissues. Wear chemical splash goggles, chemical-resistant gloves, and a chemical-resistant apron.

Procedure:

Part 1Physical Properties

1. Observe and record the color of each element on the Data Table. Is the sample silver, gray, colored, etc . . . .? Be very specific in recording observations.

2. Observe and record the luster of each element on the Data Table. Is the sample lustrous and shiny, slightly shiny, dull?

3. Record any other physical properties that are observed about the element on the Data Table. Be specific in your observations. What form is the sample in? Is the sample crystalline, flaky, rough, smooth, flat and plate-like, rocky, in strips? Is there any odor or are any vapors given off? (Note: Avoid breathing any vapors directly. Instead of smelling a sample directly, waft the vapors form the sample toward our nose.)4. Determine whether each element is malleable or brittle. To do this, position a nail on the sample and gently tap the nail with a hard, solid object (such as a small piece of wood). A material is malleable if it flattens or bens without shattering. A sample is brittle if it shatters or cracks into pieces when struck. Record your results on the Data Table.

5. Test the conductivity of the eight samples. Touch both electrodes to the element being tested, being sure that the electrodes are not touching each other. Red LED off Green LED off Low or None, Red LED dim Green LED off Low, Red LED medium Green LED off medium, Red LED bright Green LED dim high, Red LED very bright Green LED medium very high

Part 2Chemical Properties1. Determine the reactivity with acid of each sample by adding one pipetful (about 2-3 mL) of 1 M hydrochloric acid to each tube. (Note: Evidence for a chemical reaction may be the formation of gas bubbles and/or discoloration on the surface of the element. Some reactions may be slow to startbe patient.)2. Observe each tube for approximately 3-5 minutes and record results in the Data Table.

3. Determine the reactivity with cupric chloride solution of each sample by adding one pipetful (about 2-3 mL) of 0.1 M cupric chloride to each tube. (Note: Evidence for a chemical reaction may be the formation of gas bubbles and/or discoloration on the surface of the element. Some reactions may be slow to startbe patient.)4. Observe each tube for approximately 3-5 minutes and record results in the Data Table.

Disposal:

Decant the liquid from the tubes into the liquid waste container provided by your teacher and dispose of the solids in the solid waste disposal. Rinse out the tubes with water for the next step.

Post-Lab Questions:

1. Review the data gathered for the eight elements. Sort the eight elements into groups based on similarities and differences in their physical and chemical properties. From the information provided in the background reading, classify each element as metals, nonmetals, or metalloids.

metals - ________________________________________________________________

nonmetals - _____________________________________________________________

metalloids - _____________________________________________________________

2. Are there any inconsistencies within the groups you made? Do any elements seem to have properties of both groups? Which? Explain.

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

3. Look at the location on the periodic table of each of the eight elements tested n this lab. How do the properties of these elements compare to their general position on the periodic table? Make generalizations about the position of the metals, nonmetals, and metalloids on the periodic table.

___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

4. Predict the physical and chemical properties of the following elements which were not tested in this lab.

selenium - _________________________________________________________________

_________________________________________________________________________

calcium - __________________________________________________________________

_________________________________________________________________________ cobalt - ___________________________________________________________________

Data Table: Metal, Nonmetal, or Metalloid?

ElementChemical SymbolColorLusterOther Physical PropertiesResult of TappingReaction with HClReaction with CuCl2Conductivity

Aluminum

Carbon

Copper

Iodine

Magnesium

Silicon

Sulfur

Zinc

EXPERIMENT 2 :

Properties of Ionic Compoundshat parts of your body are ionic compounds? Those that compose your skin? Your hair? Actually, most of thehuman body is composed of nonionic compounds. But, you could not live without sodium chloride and other ionic compounds found inside you. How can you distinguish ionic compounds from other types of compounds? By investigating sodium chloride, you will explore some of the common properties of ionic compounds.ProblemWhat are some of the properties of ionic compounds?

aims Compare and contrast ionic compounds with a nonionic compound. Explain the differences in the conductivity of ionic compounds in different forms.

MaterialsNaCl, NaCl, LiClsugar (sucrose) crucibleBunsen burner

ring stand and clampwire gauze conductivity indicator100-mL beaker crucibleclay triangle distilled waterSafety Precautions

Always wear safety goggles and a lab apron. Hot objects will not appear to be hot. Be careful when handling any material that has been heated. Do not touch or taste any chemicals used or formed in the laboratory. Do not touch both electrodes on the conductivity indicator at the same timea small electrical jolt could result.

LABORATORY MANUALPart A : Melting Point1. Set up the apparatus as shown in Figure A.Ring standCrucibleRing clamp Clay triangle Bunsen burnerFigure A

2. Sprinkle a pea-sized pile of NaCl in the crucible and heat it with a low flame until the NaCl melts, or for 2 minutes, whichever comes first.If the salt melts within the 2-minute period, record the melting point as low. If the salt does not melt within 2 minutes, record the melting point as high.3. In the fume hood, and using the same apparatus shown in Figure A, repeat step 2 for sugar. (Note: Like most compounds in living organisms, sugar is nonionic.) Make sure the flame is the same setting as your burner in step 2.Part B : ConductivitySolid1. On a piece of paper, make a small pile of NaCl, about the size of three peas. Place the contacts of the conductivity indicator in the pile. Record the results.Solution2. Pour about 50 mL of distilled water into a clean100-mL beaker. Notice that like most ionic substances, NaCl dissolves easily in water.3. Making sure that you have wiped off the contact wires, place the conductivity indicator inthe distilled water. Record the results in the data table.4. Transfer and dissolve the pile of NaCl into the distilled water. Dissolving in water is another

property shown by many ionic compounds. Place the conductivity indicator in the salt solution. Record the results.4. Repeat step 3 with an equal amount of sugar. (Note: Some nonionic compounds dissolve in water, but many do not.)Molten5. Set up the apparatus as shown in Figure A.6. In a clean, dry crucible, mass out approximately1 g of lithium chloride, LiCl, another typical ionic compound. (The melting point of sodium chloride, NaCl, is too high to observe using classroom laboratory equipment.)7. Before heating it, place the conductivity indicator in the solid LiCl. Record the results.8. Place the crucible in the clay triangle and heat the crucible until the LiCl melts. This may take several minutes.9. Quickly turn off the burner and plunge the clean contact wires of the conductivity indicator into the molten LiCl. Record your observations.10. Remove the conductivity indicator, allow the wires to cool, and then carefully clean the contact wires.11. CAUTION: Do NOT touch the crucible until after it has cooled for about 10 minutes.HypothesisCleanup and Disposal1. Follow your teachers directions for disposing of the LiCl.2. Make sure your balance is left in the same condition as you found it.3. Be careful that your burner and clamp are cooled before putting them away.4. Carefully return all laboratory equipment to the proper place and dispose of all waste in the des- ignited containers

Name: Section:

Lab Partner:

Experiment Date:

properties of ionic compounds Part B: Melting PointObservations about the melting point of NaCl (high or low melting point)Observations about the melting of sugar (high or low melting point)Part C: ConductivityConductivity Indicator Conductor RatingTest Substance(Record light as off, dull, bright, or blinking)(good, poor, or none)Solid NaCl

Distilled waterNaCl dissolved in distilled waterSugar dissolved in distilled waterSolid LiCl

Molten LiCl

1. Sodium chloride and lithium chloride are typical ionic compounds, while sugar represents a typical nonionic compound. In general, how do these two types of compounds compare in their melting points?2. In Part C, why was it important to use distilled water instead of tap water for the conductivity measure?

LABORATORY MANUALExperiment 3 :

Single Replacement Reactions & Battery LabAimsThe aims of this laboratory are to:

a) Perform and observe the results of a variety of single replacement reactions, b) Become familiar with some of the observable signs of these reactions,

c) Predict and identify the products formed in each of these reactions,

d) Write balanced chemical equations for each single replacement reaction. e) Make three voltaic cells by using a salt bridge, a citrus fruit and potato.

f) Understand the function of a salt bridge.

Single Replacement ReactionsIn Part A of this lab we will examine Single Replacement Reactions. This is one type of oxidation reduction reaction, or redox reaction, because it occurs via a transfer of electrons. All single replacement reactions have the general form:

A + BC B + ACHere, A is an element and BC is usually an aqueous ionic compound or an acid (consisting of B+ and C- aqueous ions). Element A replaces B in BC, resulting in the formation of a new element B and a new ionic compound or acid, AC. If the new element B is a metal, it will appear as a metallic deposit. If it is a gas, it will appear as bubbles.

ProcedureSafetyBe especially cautious when using the 6M HCl, and 3M H2SO4. These substances can burn your skin. Also be aware that skin discoloration will result from contact with AgNO3. If you feel any tingling sensations or see any color changes on your skin, flush with water immediately for a minimum of 15 minutes. Inform your instructor of any chemical contact as soon as possible.

Materials and EquipmentSolids (at front of lab): Copper metal, zinc metal, magnesium metal, solid sodium bicarbonate, copper metal plate, clean and shiny pennies, nickels and dimes

Solutions (in hoods on both sides of lab): 3M sulfuric acid, 6M hydrochloric acid, 1M sodium chloride, all other solutions are 0.1M and include silver nitrate, lead(II) nitrate, copper(II) sulfate, zinc nitrate, nickel(II) nitrate, aluminum sulfate

Equipment: 5 medium test tubes, plastic test tube rack, voltmeters, paper towels, aluminum foilPart A: Single Replacement Reactions1. Use the medium sized test tubes. Always use clean test tubes that have been rinsed with distilled water. The test tubes do not have to be dry. 2. Use approximately 3-mL quantities of all solutions. A good estimate is to use two full dropper squirts of each chemical.

3. Place one piece of metal in the test tube first, and then add the solution. The metal should be completely immersed in the solution used. If results are not obtained immediately, give the reaction some time. Some reactions take longer than others.

4.

Perform the following reactions, and record your observations for each on the data sheet. All waste is to be disposed of in the plastic container in the hood!a.Zinc metal + hydrochloric acid

b.Copper metal + aqueous silver nitrate c. Copper metal + aqueous zinc nitrate d.Zinc metal + aqueous lead(II) nitrate e. Magnesium metal + sulfuric acid

Part B: BatteriesSalt Bridge Battery1.Into a 250-mL beaker add approximately 25 mL of 1M copper(II) sulfate. (This is the cathode.) Label as Beaker #1.

2.

Into another 250-mL beaker, add approximately 25 mL of 1M zinc sulfate. (This is the anode.) Label as Beaker #2.

3.

Connect the solutions in the beakers by placing one end of a 10- inch piece of cotton twine into Beaker #1 and the other end into the Beaker #2. Obtain twine which has been soaked in a concentrated potassium sulfate solution from your instructor. (The twine is the salt bridge.)

4.

Place a polished piece of copper metal plate into Beaker #1. Connect to voltmeter using wire clips.

5.

Place a polished piece of zinc metal plate into Beaker #2. Connect to voltmeter using wire clips.

6.Turn voltmeter to 2V and record the voltage.7.Remove salt bridge. Record the voltage.

Citrus Cell Battery1.Cut a lemon or grapefruit in half across the segments.

2.

Place the polished piece of zinc metal plate into one half of the fruit. Connect to voltmeter using wire clips.

3. Place a polished piece of copper metal plate into the other half of the fruit. Connect to voltmeter using wire clips.

4.Turn voltmeter to 2V and record the voltage.

5.Repeat 1- 4 with a potato. Record your observations.

Coin Battery1.Obtain three coins from your instructor. Cut 4 circles of paper towel slightly larger than the coins.

2.Soak the paper towels in a beaker containing 20 mL of a 1M sodium chloride solution.

3.Make a coin batter by placing a coin, a layer of NaCl-soaked paper towel, a different type of coin in a stack. Do not allow the coins to touch.4.Record the voltage.Name:

Date:

Lab Partner:

Lab Section:

Single Replacement Reactions & Battery LabPart A:For each of the reactions performed:-- record your observations

-- predict the names and states of the products formed

-- write the balanced equation, including all physical states and

-- write the individual oxidation states for each atom.

a. Zinc metal + hydrochloric acidObservations:Product Names & States (if none, why not?):Balanced Equation with Individual Oxidation Numbers above elements:b. Copper metal + aqueous silver nitrateObservations:Product Names & States (if none, why not?):Balanced Equation with Individual Oxidation Numbers above elements:c. Copper metal + aqueous zinc nitrateObservations:Product Names & States (if none, why not?):Balanced Equation with Individual Oxidation Numbers above elements:d. Zinc metal + aqueous lead(II) nitrateObservations:Product Names & States (if none, why not?):

Balanced Equation with Individual Oxidation Numbers above elements:e. Magnesium metal + sulfuric acidObservations:Product Names & States (if none, why not?):Balanced Equation with Individual Oxidation Numbers above elements:Part B: BatteriesSalt Bridge Battery1. Voltage of Salt Bridge Battery with Salt BridgeVoltage V

2. Voltage of Salt Bridge Battery without Salt BridgeVoltage V

Citrus Cell Battery/1. Type of Citrus Fruit Used2. Voltage of Citrus Fruit BatteryVoltage V

3. Voltage of Potato BatteryVoltage V

Coin Battery1. Complete the following table which represents your coin battery.Top Layer:NaCl Soaked Paper Towel

Coin:

Center Layer:NaCl Soaked Paper Towel

Coin:

Bottom Layer:NaCl Soaked Paper Towel

2. Voltage of Coin BatteryVoltage V

Questions:1. What happened when the salt bridge was removed from the salt bridge battery. Explain results.

2. What acid acts an electrolyte in the citrus fruit battery?

3. Which type of battery produced the greatest voltage? Why?EXPERIMENT 4 :

Double Replacement Reactions/Aims :The aims of this lab are to:

a) Perform and observe the results of a variety of double displacement reactions, b) Become familiar with some of the observable signs of these reactions,

c) Identify the products formed in each of these reactions,

d) Write balanced chemical equations for each double displacement reaction studied.

Double Displacement ReactionsAll double displacement reactions have the general form: AB + CD AD + CBProcedureSafetyBe especially cautious when using the 6M HCl, 3M H2SO4 and 6M NaOH as they can burn your skin. Also be aware that skin discoloration will result from contact with AgNO3. If you feel any tingling sensations or see any color changes on your skin, flush with water immediately for a minimum of 15 minutes. Inform your instructor of any chemical contact as soon as possible.

Materials and EquipmentSolids: solid sodium bicarbonate

Solutions: 6M sodium hydroxide, 3M sulfuric acid, 6M hydrochloric acid; all other solutions are

0.1M and include silver nitrate, sodium chloride, iron(III) chloride, ammonium hydroxide, sodium carbonate, cobalt(II) nitrate, sodium phosphate, copper(II) sulfate, potassium nitrate, nickel(II) nitrate, barium chloride.

Equipment: 9 small test tubes, plastic test tube rack

Instructions for Performing Reactions

Use approximately 3-mL quantities of all solutions. A good estimate is to use three full dropper squirts of each chemical.

Perform the following reactions, and record your observations for each on the data sheet. If results are not obtained immediately, give the reaction some time. Some reactions take longer than others. All waste is to be disposed of in the plastic container in the hood!1.Aqueous sodium chloride + aqueous silver nitrate

2.Aqueous sodium phosphate + aqueous copper(II) sulfate

3.Hydrochloric acid + solid sodium bicarbonate (just a small scoop)

4.Aqueous nickel(II) nitrate + aqueous sodium hydroxide

5.Aqueous barium chloride + sulfuric acid

6.Hydrochloric acid + aqueous sodium hydroxide

7.Aqueous sodium carbonate + aqueous cobalt(II) nitrate

8.Aqueous sodium chloride + aqueous potassium nitrate

9.Aqueous iron(III) chloride + aqueous ammonium hydroxide

When finished, complete the data sheet by writing the balanced equation for each reaction.

Name:

Chem 9, Section:

Lab Partner:

Experiment Date:

//Double Replacement ReactionsFor each of the reactions performed:-- predict the reaction type (precipitation, neutralization or gaseous)

-- record your observations

-- predict the names and states of the products formed

-- write the balanced equation, including all physical states.

1. Aqueous sodium chloride + aqueous silver nitrateReaction Type:

Observations:Product Names & States (if none, why not?):

Balanced Equation:

2. Aqueous sodium phosphate + aqueous copper(II) sulfateReaction Type:


Balanced Equation:

3. Hydrochloric acid + solid sodium bicarbonateReaction Type:


Balanced Equation:

4. Aqueous nickel(II) nitrate + aqueous sodium hydroxide

Reaction Type:


Balanced Equation:

5. Aqueous barium chloride + sulfuric acidReaction Type:


Balanced Equation:

6. Hydrochloric acid + aqueous sodium hydroxideReaction Type:


Balanced Equation:

7. Aqueous sodium carbonate + cobalt(II) nitrateReaction Type:


Balanced Equation:

8. Aqueous sodium chloride + aqueous potassium nitrateReaction Type:


Balanced Equation:

9. Aqueous iron(III) chloride + aqueous ammonium hydroxide

Reaction Type:


Balanced Equation:

EXPERIMENT 5 :

//pH Measurement and its ApplicationsAimas:To measure the pH of various solutions using pH indicators and meter.

To create and study the properties of buffer solutions.

Background:Part A. Using Indicators to Measure pHIn this part of the experiment you will use five pH indicators to determine the pH of four solutions to within one pH unit. An acid-base indicator is a chemical that undergoes a distinct color change at a specific pH. In order for an indicator to be effective, a small quantity (usually one or two drops) of indicator is all that should be required to observe this color change. We can represent the chemical reaction that an acid-base indicator undergoes during a color change as:

Part B. Using pH MetersIn this part of the experiment you will learn to use a pH meter to measure pH. Your instructor will demonstrate how to use the pH meter appropriately at the beginning of your laboratory session.

PH meter calibration

Calibration Procedure

1.Rinse the electrode with distilled water.

2.Place the electrode in a pH = 7.00 buffer solution.

3.Wait a for the meter to stabilize, then adjust the meter until it reads a pH of 7.00.

4.Remove the electrode from the solution and rinse it with distilled water.

5.Place the electrode in the second buffer solution (pH = 4.00 or 10.00 buffers).

6.Wait a moment for the meter to stabilize, then adjust the meter until it displays the same pH as the buffer.

7.Remove the electrode from the second buffer solution and rinse it with distilled water.

8.Re-place the electrode in the pH = 7.00 buffer solution. If the reading does not return 7.00, then repeat the calibration procedure using both buffers.

Part C : Buffer SolutionsIn this part of the experiment you will prepare a buffer solution of a pH specified by your instructor u.

To do so you will use Equation (7), solving for [A] / [HA], to determine the amount of each solution you will need to use to prepare the buffer. You will confirm the pH of this solution using your pH meter.

Finally, you will compare the buffering capacity of the buffer you prepare with that of deionized water.

Procedure:Materials and Equipment:You will need the following additional items for this experiment:

pH meter

magnetic stirrer and stir-bar

50-mL buretSafety:GENERAL SAFETY: Students must wear safety goggles and lab coats at all times.

GLOVES: Gloves are needed when handling:

zinc sulfate

sodium carbonate

sodium bisulfate

methyl yellow

congo red

bromocresol green

phenolphthalein

unknown acid

WASTE DISPOSAL: All chemicals used must go in the proper waste container for disposal.

Procedure:Part A. Determination of pH using Acid-Base Indicators1. Rinse five small test tubes using deionized water (there is no need to dry these). To

each of these test tubes add about 1 mL of 0.1-M HCl(aq). (Estimate these volumes). To each of these test tubes add one of the five indicators listed in Table 1. Be sure to

arrange or label your test tubes so that you know which indicator was added to which tube.

2. By comparing the colors you observe in each tube you should be able to determine the pH of the 0.1-M HCl solution to within one pH unit (see background discussion). Record your color observations and your determination of the pH range of the 0.1-M HCl solution on your data sheet.

3. Repeat the same procedure using each of the following solutions:

0.1-M sodium hydrogen phosphate, NaH2PO4(aq)

0.1-M acetic acid, CH3COOH(aq)0.1-M zinc sulfate, ZnSO4(aq)4. Record your results for each on your data sheet.

Part B. Using pH MetersYour instructor will demonstrate the proper use of the pH meters.1. Rinse four small 100 or 150-mL beakers several times using deionized water. Do not use any soap as the residue may affect your pH measurements.

2. Into each of your four clean beakers collect about 30 mL of one of the following:

0.1-M sodium chloride, NaCl(aq)

0.1-M sodium carbonate, Na2CO3(aq)0.1-M sodium acetate, NaCH3COO(aq)0.1-M sodium hydrogen sulfate, NaHSO4(aq)3. Use your pH meter to determine the pH of each of these four solutions. Record the results on your data sheet. Add a drop or two or bromcresol green indicator to each of these solutions. Record the color of the indicator in each solution on your data sheet.

Part C : Buffer Solutions prepare a buffer solution that will maintain the pH assigned to you by your instructor (see background section). It is suggested you use only a portion of each of these two solutions in case your first attempt does not succeed.

Use your pH meter to confirm the pH of your buffer solution. Your measured pH value should be within 0.2 pH units of your assigned value. Record your measured value on your data sheet and obtain your instructors initials confirming your success.

Now we will test the buffer solution you prepared against changes in pH.

Rinse and fill another 150-mL beaker with a volume of deionized water equal to that of your buffer solution. Using your pH meter measure the pH of the deionized water. Do not be alarmed if this pH is less than neutral. It should be between 5.2 and 7.0. Do you know why? What species from the atmosphere dissolves in water that is left standing and lowers the pH?Add 5 drops of the remaining 0.2 M NaOH solution to both the beaker containing your buffer solution and that containing the deionized water. Measure the pH of each of these solutions following this addition and determine the change in pH of each. Record these values on your data sheet.

Clean up. Discard all chemicals in the proper chemical waste container. Clean and then return all borrowed equipment to the stockroom.

Name:

Date:

Lab Partner:

Lab Section:

//Lab Report: pH Measurement and its Applications Part A Determination of pH using Acid-Base Indicators

Record the colors of the indicators observed for each solution tested. Then use these colors and

Table 1 to estimate the pH range of each solution (for example, pH =1-2).Indicator used0.1-M HCl0.1-M NaH2PO40.1-M CH3COOH0.1-M ZnSO4

Methyl violet

Thymol blue

Methyl yellow

Congo Red

Bromcresol green

pH range

/ Consider your results for the solutions of 0.1-M HCl and 0.1 M CH3COOH. Which has the lower pH and why is its pH lower?

/ Consider your results for the 0.1-M ZnSO4 solution. Is the solution acidic or basic?

Which ion, Zn2+ or SO4

, is causing the observed acidity or basicity?

2

Write the net ionic equation below that shows why this ion is acidic or basic:

Part B Using pH Meters

Record the measured pH and the color of bromcresol green indicator observed for each solution.0.1-M NaCl0.1 M-Na2CO30.1 M-CH3COONa0.1 M NaHSO4

Measured pH

Color in indicator

Consider your results for the 0.1-M NaCl solution. Is the color obtained when tested with bromcresol green indicator as expected? Explain.

Consider your results for the 0.1-M Na2CO3 solution. Is the solution acidic or basic?

/Which ion, Na+ or CO3

is causing the observed acidity or basicity?

Write the net ionic equation below that shows why this ion is acidic or basic:

Consider your results for the 0.1-M NaHSO4 solution. Is the solution acidic or basic?

/Which ion, Na+ or HSO4

is causing the observed acidicity or basicity?

/Write the net ionic equation below that shows why this ion is acidic or basic:

Part C Buffer Solutions

Record your results below.

pH of Buffer Assigned by Instructor:

Measured pH of Assigned Buffer:

Instructors Initials:

Show the calculations you used and detail the steps you followed to prepare this buffer solution including the volumes of all solutions used:

Compare the pH change of the buffer prepared above to that of deionized water upon the addition of a strong base by recording the following values:

Deionized WaterBuffer Solution

pH before adding NaOH:

pH after adding 5 drops of NaOH:

pH change:

Briefly explain why the buffer is more resistant to a change of pH upon addition of the base than the water. Use equations to support your explanation:

Why isnt the measured pH of the deionized water before adding the NaOH(aq) equal to 7.0?

HAZARDEXAMPLESPRECAUTIONREMEDYSpecial disposal procedures need to be followed.certain chemicals, living organismsDo not dispose of these materials in

the sink or trash can.Dispose of wastes as directed by your teacher.Organisms or other biological materials that might be harmful to humansbacteria, fungi, blood, unpreserved tissues, plant materialsAvoid skin contact with these materials. Wear mask or gloves.Notify your teacher if you suspect contact with material. Wash hands thoroughly.Objects that can burn skin by being too cold or too hotboiling liquids, hot plates, dry ice, liquid nitrogenUse proper protection when handling.Go to your teacher for first aid.Use of tools or glassware that can easily puncture or slice skinrazor blades, pins, scalpels, pointed tools, dissecting probes, broken glassPractice common- sense behavior and follow guidelines for use of the tool.Go to your teacher for first aid.Possible danger to respiratory tract from fumesammonia, acetone, nail polish remover, heated sulfur, moth ballsMake sure there is good ventilation. Never smell fumes directly. Wear a mask.Leave foul area and notify your teacher immediately.Possible danger from electrical shock or burnimproper grounding, liquid spills, short circuits, exposed wiresDouble-check setup with teacher. Check condition of wires and apparatus.Do not attempt to fix electrical problems. Notify your teacher immediately.Substances that can irritate the skin or mucus membranes of the respiratory tractpollen, moth balls, steel wool, fiber glass, potassium permanganateWear dust mask and gloves. Practice extra care when handling these materials.Go to your teacher for first aid.Chemicals that can react with and destroy tissue and other materialsbleaches such as hydrogen peroxide; acids such as sulfuric acid, hydrochloric acid; bases such as ammonia, sodium hydroxideWear goggles, gloves, and an apron.Immediately flush the affected area with water and notify your teacher.Substance may be poisonous if touched, inhaled, or swallowedmercury, many metal compounds, iodine, poinsettia plant

partsFollow your teachers instructions.Always wash hands thoroughly after use. Go to your teacher for first aid.Open flame may ignite flammable chemicals, loose clothing, or hairalcohol, kerosene, potassium permanganate, hair, clothingTie back hair. Avoid wearing loose clothing. Avoid open flames when using flammable chemicals. Be aware of locations of fire safety equipment.Notify your teacher immediately. Use fire safety equipment if applicable.

Eye Safety

Proper eye

protection should be worn at all times.

Clothing Protection This symbol appears when

substances could stain or burn clothing.

Animal Saafety

This symbol appears when safety of animals and students must be ensured.

Radioactivity

This symbol appears when radioactive materials are used.

W

2

chemistry practical

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