Chapter 1 IB Chemistry Warm

Ups Stoichiometry

Mrs. Hilliard

Vocabulary

1.Atomic theory

2.Kelvin

3.Mole

4.Relative abundance

5.Molar Mass

6.Empirical formula

7.Molecular formula

8.Stoichiometry

9.Percentage yield

10.Limiting Reagent

11.Theoretical yield

12.Experimental yield

13.Standard Temperature and

Pressure (STP)

14.Avogadro’s law

15.Molar concentration

Vocabulary1. Atomic theory- all matter is composed of atoms which

cannot be created or destroyed during chemical

reactions.

2. Kelvin- the SI unit for temperature.

3. Mole- the SI base unit used to measure the amount of a substance, equal to 6.02 x 10 23 particles.

4. Relative abundance- a measure of the percentage that occurs in a sample of the element.

5. Molar Mass- the mass in grams of one mole of any substance.

6. Empirical formula- the simplest whole-number ratio of atoms of each element present in a compound.

7. Molecular formula- the actual number of atoms of each element in one molecule of a substance.

8. Stoichiometry- the quantitative method of examining the relative amounts of reactants and products.

9. Percentage yield- the ratio of actual yield to theoretical yield expressed as a percent.

10. Limiting Reagent- the reagent that is totally consumed during a chemical reaction, limits the extent of the

reaction, and determines the amount of product.

11. Theoretical yield- the maximum amount of product that can be produced from a given amount of

reactant.

12. Experimental yield- the actual amount of product that is produced in a chemical reaction.

13. Standard Temperature and Pressure (STP)- a standard temperature of 273K and pressure of 100kPa.

14. Avogadro’s law- equal volumes of any gas measured at the same temperature and pressure contains the

same number of molecules.

15. Molar concentration- the amount in mol of a substance dissolved in 1 dm3 of solvent.

Balancing Equations

1. What is the sum of the coefficients for the equation when balancing using the smallest

possible whole numbers?

2. What is the sum of all coefficients when the following equation is balanced using the

smallest whole numbers? C4H10 + O2 → CO2 + H2O

3. 9 molecules of Calcium, Ca, and 6 molecules of chlorine gas, Cl2 (g), were mixed together

under conditions which allowed the reaction to go to completion, according to the

following equation. The following diagram represents the mixture of reactants. Which

reaction diagram represents the reaction mixture when the reaction was complete?

Key: Purple= Chlorine

Green= CalciumA B C D

Balancing Equations

1. What is the sum of the coefficients for the equation when balancing using the smallest

possible whole numbers? 11

2. What is the sum of all coefficients when the following equation is balanced using the

smallest whole numbers? 2C4H10 + 13O2 → 8CO2 + 10H2O = 33 total

3. 9 molecules of Calcium, Ca, and 6 molecules of chlorine gas, Cl2 (g), were mixed together

under conditions which allowed the reaction to go to completion, according to the

following equation. The following diagram represents the mixture of reactants. Which

reaction diagram represents the reaction mixture when the reaction was complete?

Key: Purple= Chlorine

Green= CalciumA B C D

1 6 4

Balancing Equations

4. What is the coefficient of Fe3O4 when the following equation is balanced

using the lowest whole numbers? Fe3O4 + C → Fe + CO

5. What is the coefficient for O2(g) when the equation for the combustion of

1 mole of propane is balanced? C3H8 + O2 → CO2 + H2O

6. Which coefficients would balance this equation?

__HCl + __SnO2 → __SnCl2 + __Cl2 + __H2O

7. What is the coefficient for MgSO4 (aq) when the following equation is

balanced, using the smallest possible integers?

__Mg3N2 + __H2SO4 → __MgSO4 + __(NH4)2SO4

A. 1 2 1 1 3

B. 4 1 1 1 2

C. 1 4 2 1 1

D. 3 1 1 1 2

Balancing Equations

4. What is the coefficient of Fe3O4 when the following equation is balanced

using the lowest whole numbers? 1 1Fe3O4 + 4C → 3Fe + 4CO

5. What is the coefficient for O2(g) when the equation for the combustion of

1 mole of propane is balanced? 3 1C3H8 + 5O2 → 3CO2 + 4H2O

6. Which coefficients would balance this equation?

__HCl + __SnO2 → __SnCl2 + __Cl2 + __H2O

7. What is the coefficient for MgSO4 (aq) when the following equation is

balanced, using the smallest possible integers? 3

_1_Mg3N2 + _4_H2SO4 → _3_MgSO4 + _1_(NH4)2SO4

A. 1 2 1 1 3

B. 4 1 1 1 2

C. 1 4 2 1 1

D. 3 1 1 1 2

Molar Mass8. What is the approximate molar mass, in g mol-1, of MgSO4 ● 3 H2O?

9. The molar mass of a compound is approximately 125 g mol-1. Which formula is possible

for this compound?

A. KOH

B. AgOH

C. NaNO3

D. MgO

10. Which non-metal forms an oxide XO2 with a relative molecular mass of 46?

A. Si

B. S

C. C

D. N

Molar Mass8. What is the approximate molar mass, in g mol-1, of MgSO4 ● 3 H2O? 174

9. The molar mass of a compound is approximately 125 g mol-1. Which formula is possible

for this compound?

A. KOH

B. AgOH

C. NaNO3

D. MgO

10. Which non-metal forms an oxide XO2 with a relative molecular mass of 46?

A. Si

B. S

C. C

D. N

Mole calculations

11. How many molecules are present in a drop of ethanol, C2H5OH, of mass

1.7 x 10 -2 g?

12. What sample has the greatest mass?

A. 2 mol of KOH

B. 1 mol of SO2

C. 4 mol of H2O

D. 2 mol of Ar

13. What is the total number of carbon atoms contained in 1.5 mol of

glucose, C6H12O6?

Mole calculations

11. How many molecules are present in a drop of ethanol, C2H5OH, of mass

1.7 x 10 -2 g? 2.2 x 10 20

12. What sample has the greatest mass?

A. 2 mol of KOH

B. 1 mol of SO2

C. 4 mol of H2O

D. 2 mol of Ar

13. What is the total number of carbon atoms contained in 1.5 mol of

glucose, C6H12O6? 6 carbon atoms in glucose= 6 mol of C 1.5 mol x 6 mol

C= 9 mol C x (6.02 x 10 23) = 5.42 x 10 24

Mole calculations

14. What is the mass, in g, of one molecule of ethanol, C2H5OH?

15. What is the total number of nitrogen atoms in three mol of NH4NO3?

16. What is the number of oxygen atoms in one mole of CuSO4 ● 4H2O?

17. Which sample has the greatest mass?

A. 1.5 x 10 2 g of Copper

B. 1.3 x 10 24 atoms of gold

C. 5.0 mol of Ne

D. 6.0 x 10 25 molecules of hydrogen

Mole calculations

14. What is the mass, in g, of one molecule of ethanol, C2H5OH? 7.68 x 10 -23

15. What is the total number of nitrogen atoms in three mol of NH4NO3? 3.61 x

10 24

16. What is the number of oxygen atoms in one mole of CuSO4 ● 4H2O? O= 8

in 1 mole 8 x (6.02 x 10 23)= 4.82 x 10 24

17. Which sample has the greatest mass?

A. 1.5 x 10 2 g of Copper

B. 1.3 x 10 24 atoms of gold

C. 5.0 mol of Ne

D. 6.0 x 10 25 molecules of hydrogen

Mole calculations and

empirical formulas18. How many oxygen atoms are there in 0.30 mol of ethanoic acid,

CH3COOH?

19. The relative molecular mass of a gas is 56 and its empirical formula is CH2.

What is the molecular formula of the gas?

20. Which is both an empirical and a molecular formula?

A. CH4

B. C6H12O6

C. C2H4

D. C3H6

Mole calculations and

empirical formulas18. How many oxygen atoms are there in 0.30 mol of ethanoic acid,

CH3COOH? 2 oxygen in 1 mol ethanoic acid 2 mol oxygen x 0.30 mol =

0.6 mol oxygen x (6.02 x 10 23)= 3.61 x 10 23

19. The relative molecular mass of a gas is 56 and its empirical formula is CH2.

What is the molecular formula of the gas? 56/14= 4 C4H8

20. Which is both an empirical and a molecular formula?

A. CH4

B. C6H12O6

C. C2H4

D. C3H6

Molecular formulas and

empirical formulas21. On analysis, a compound with a molar mass 64 g mol-1 was found to contain 2 g of

hydrogen, 14g of nitrogen and 16 g of oxygen. What is the molecular formula of the compound?

22. Equal masses of the metals Be, Mg, Au, and Ca are added to separate sample of excess

HCl (aq). Which metal produces the greatest total volume of H2 (g)?

23. Which compound has the empirical formula with the largest mass?

A. C2H6

B. C2H12

C. C2H4

D. C3H6

Molecular formulas and

empirical formulas21. On analysis, a compound with a molar mass 64 g mol-1 was found to contain 2 g of

hydrogen, 14g of nitrogen and 16 g of oxygen. What is the molecular formula of the compound? 2 g H +14g N + 16g O = 32 g NO 64g/32g= 2 H4N2O2

22. Equal masses of the metals Be, Mg, Au, and Ca are added to separate sample of excess

HCl (aq). Which metal produces the greatest total volume of H2 (g)? Be

23. Which compound has the empirical formula with the largest mass?

A. C2H6

B. C2H12

C. C2H4

D. C3H6

Molecular formulas,

empirical formulas, Stoichi.24.5.00 mol of a hydrocarbon with an empirical formula of CH2

has a mass of 140 g. What is the molecular formula of this

compound?

25.4.0 mol of aluminum reacts with oxygen to form aluminum

oxide. What is the amount of oxygen, in mol, needed for

complete reaction?

26.What mass, in g, of hydrogen is formed when 2 mol of

aluminum react with excess hydrochloric acid according to

the following equation? 2 Al (s) + 6 HCl (aq) → 2 AlCl3(aq) + 3 H2 (g)

Molecular formulas,

empirical formulas, Stoichi.24. 5.00 mol of a hydrocarbon with an empirical formula of CH2 has a mass of

140 g. What is the molecular formula of this compound? 140g/ 14g= 10

mol/ 5 mol = 2 C2H4

25. 4.0 mol of aluminum reacts with oxygen to form aluminum oxide. What is

the amount of oxygen, in mol, needed for complete reaction? 3 mol O2

26. What mass, in g, of hydrogen is formed when 2 mol of aluminum react

with excess hydrochloric acid according to the following equation?

2 Al (s) + 6 HCl (aq) → 2 AlCl3 (aq) + 3 H2 (g)

2 mol Al x 3 mol H2/ 2 mol Al x 2.016 g H2/ 1 mol H2 = 6.048 g H2

Stoichiometry27.What is the maximum mass, in g, of calcium oxide that

can be obtained from the reaction of oxygen with 2.4

g of calcium?

28.Air bags in cars inflate when sodium azide

decomposes to form sodium and nitrogen:

2NaN3 (s) →2 Na (s) + 3 N2 (g) Calculate the

amount, in moles, of nitrogen gas produced by the

decomposition of 4.6 mol of NaN3 (s).

Stoichiometry27.What is the maximum mass, in g, of calcium oxide that

can be obtained from the reaction of oxygen with 2.4

g of calcium? 2.4 g Ca x 1/ 40.08g Ca x 2 mol CaO/2

mol Ca x 56 g CaO/ 1 mol = 3.4 g CaO

28.Air bags in cars inflate when sodium azide

decomposes to form sodium and nitrogen:

2NaN3 (s) →2 Na (s) + 3 N2 (g) Calculate the

amount, in moles, of nitrogen gas produced by the

decomposition of 4.6 mol of NaN3 (s). 6.9 mol N2

Stoichiometry and Limiting

Reagents29. Chloroethene, C2H3Cl, reacts with oxygen according to the equation

below. What is the amount, in mol, of H2O produced when 5.0 mol of

C2H3Cl and 5.0 mol of O2 are mixed together, and the above reaction

goes to completion?

2 C2H3Cl (g) + 5 O2 (g) → 4 CO2 (g) + 2 H2O(g) + 2 HCl (g)

30. 7 dm3 of carbon monoxide, CO (g), and 3 dm3 of oxygen, O2 (g), at the

same temperature and pressure are mixed together. Assuming complete

reaction according to the equation given, what is the maximum volume

of carbon dioxide, CO2 (g), in dm3, that can be formed?

2 CO (g) + O2 (g) → 4 CO2

Stoichiometry and Limiting

Reagents29. Chloroethene, C2H3Cl, reacts with oxygen according to the equation

below. What is the amount, in mol, of H2O produced when 5.0 mol of

C2H3Cl and 5.0 mol of O2 are mixed together, and the above reaction

goes to completion? 2 C2H3Cl (g) + 5 O2 (g) → 4 CO2 (g) + 2 H2O(g) + 2

HCl (g) 5.0 mol C2H3Cl x 2 mol H2O/ 2 mol C2H3Cl = 5 mol H2O

5.0 mol O2 x 2 mol H2O/ 5 mol O2 = 2 mol H2O 2.00 mol H2O

30. 7 dm3 of carbon monoxide, CO (g), and 3 dm3 of oxygen, O2 (g), at the

same temperature and pressure are mixed together. Assuming complete

reaction according to the equation given, what is the maximum volume

of carbon dioxide, CO2 (g), in dm3, that can be formed? 2 CO (g) + O2 (g)

→ 4 CO2 7 dm3 CO x 1 mol/ 22.4 dm3 CO x 4 mol CO2 / 2 mol CO x 22.4

dm3 O2 / 1mol = 14 dm3 CO2 3 dm3 O2 x 1 mol/ 22.4 dm3 O2 x 4 mol CO2 /

1 mol O2 x 22.4 dm3 O2 / 1mol = 12 dm3 O2 (limiting reagent)

Stoichiometry/ Limiting

Reagents/ and Gases31.What volume of sulfur trioxide, in cm3, can be prepared using 60

cm3 sulfur dioxide and 30 cm3 oxygen gas by the following

reaction? Assume all volumes are measured at the same

temperature and pressure. 2 SO2 (g) + O2 (g) → 2 SO3 (g)

32.What volume of carbon dioxide, in dm3 under standard

conditions, is formed when 14.00 g of ethene (C2H4, Mr = 28.1)

undergoes complete combustion?

33.The volume of an ideal gas at 35°C is increased from 3.00 dm3 to

6.00 dm3. At what temperature in °C, will the gas have the original

pressure?

Stoichiometry/ Limiting

Reagents/ and Gases31. What volume of sulfur trioxide, in cm3, can be prepared using 60 cm3 sulfur dioxide and 30

cm3 oxygen gas by the following reaction? Assume all volumes are measured at the same temperature and pressure. 2 SO2 (g) + O2 (g) → 2 SO3 (g) .06 dm3 x 1mol/22.4 dm3 x 2 mol/2

mol x 22.4 dm3 = .06 dm3 = 60 cm3 .03 dm3 x 1mol/22.4 dm3 x 2 mol/1 mol x 22.4 dm3 = .06

dm3 = 60 cm3

32. What volume of carbon dioxide, in dm3 under standard conditions, is formed when 14.00 g

of ethene (C2H4, Mr = 28.1) undergoes complete combustion? 14g C2H4, x 1mol/ 28.1g C2H4 x

2 mol CO2 / 1 mol C2H4 x 22.4 dm3 /1mol = 22.3 dm3

33. The volume of an ideal gas at 35°C is increased from 3.00 dm3 to 6.00 dm3. At what

temperature in °C, will the gas have the original pressure? V1/T1 = V2/T2 3.00 dm3/308= 6.00

dm3 /T2 = 616-273 = 343°C

Gases34. Which sample of oxygen gas, O2, contains the greatest number of oxygen

molecules?

A. 2.1 mol O2

B. 2.1 x 10 23 O2 molecules

C. 2.1 dm3 O2 at 1.01 x 10 5 Pa and 273 K

D. 2.1 g O2

35. A fixed mass of gas has a certain volume at a temperature of 100°C. What

temperature is required to double its volume while keeping the pressure

constant?

Gases34. Which sample of oxygen gas, O2, contains the greatest number of oxygen

molecules?

A. 2.1 mol O2

B. 2.1 x 10 23 O2 molecules

C. 2.1 dm3 O2 at 1.01 x 10 5 Pa and 273 K

D. 2.1 g O2

35. A fixed mass of gas has a certain volume at a temperature of 100°C. What

temperature is required to double its volume while keeping the pressure

constant? V1/T1 = V2/T2 1L/373K= 2L /T2 = 746K

Solutions36. 2.6 g of NaNO3(Mr = 85) is dissolved in water to prepare 3.0 dm3 of solution.

What is the concentration of the resulting solution in mol dm-3?

37. The graph below represents the relationship between two variables in a fixed

amount of gas. Which variables could be represented by each axis?

Y

x

X- axis Y-axis

A. Pressure Volume

B. Pressure Temperature

C. Volume Temperature

D. Temperature Volume

Solutions36. 2.6 g of NaNO3(Mr = 85) is dissolved in water to prepare 3.0 dm3 of solution.

What is the concentration of the resulting solution in mol dm-3? 2.6 g x

1mol/85g NaNO3= 0.03 mol NaNO3 M= mol/L M= 0.03mol/ 3.0 dm3 = 0.01M

37. The graph below represents the relationship between two variables in a fixed

amount of gas. Which variables could be represented by each axis?

Y

x

X- axis Y-axis

A. Pressure Volume

B. Pressure Temperature

C. Volume Temperature

D. Temperature Volume

Solutions 238. 3.5 g of NH3 are dissolved in H2O to prepare a 500 cm3 solution. Which statements are

correct?

I. [NH3] = 0.42 mol dm-3

II. NH3 is the solute and H2O is the solution

III. The concentration of the solution is 17g dm-3

39. What volume, in cm3, of 0.400 mol dm-3 HCl (aq) is required to neutralize 50.0 cm3 of 0.400 mol dm-3 Ca(OH)2 (aq)?

40. Which statement about solutions is correct?

I. The concentration of a solution is the amount of solvent dissolved in 1 dm3 of solution.

II. When vitamin D dissolves in fat, vitamin D is the solvent and fat is the solute.

III. An aqueous solution consists of water dissolved in a solute.

IV. In a solution of NaI in water, NaI is the solute and water is the solvent.

Solutions 238. 3.5 g of NH3 are dissolved in H2O to prepare a 500 cm3 solution. Which statements are correct?

I. [NH3] = 0.42 mol dm-3

II. NH3 is the solute and H2O is the solution

III. The concentration of the solution is 17g dm-3

39. What volume, in cm3, of 0.400 mol dm-3 HCl (aq) is required to neutralize 50.0 cm3 of 0.400 mol dm-3

Ca(OH)2 (aq)? 2HCl + Ca(OH)2 → 2H2O + CaCl2 0.050 dm3 x 1mol/22.4 dm3 Ca(OH)2 x 2 mol

HCl/ 1 mol Ca(OH)2 x 22.4 dm3 /1mol = .1 dm3 = 100 cm3

40. Which statement about solutions is correct?

I. The concentration of a solution is the amount of solvent dissolved in 1 dm3 of solution.

II. When vitamin D dissolves in fat, vitamin D is the solvent and fat is the solute.

III. An aqueous solution consists of water dissolved in a solute.

IV. In a solution of NaI in water, NaI is the solute and water is the solvent.

Solutions 341.What will be the concentration of sulfate ions in

mol dm-3 when 0.60 mol of Ca(SO4)2 is dissolved in

water to give 100 cm3 of aqueous solution?

42.400 cm3 of water is added to a solution of 200 cm3

of 0.4 mol dm-3 sodium chloride. What is the

concentration of sodium chloride in the new

solution?

Solutions 341.What will be the concentration of sulfate ions in mol dm-3

when 0.60 mol of Ca(SO4)2 is dissolved in water to give

100 cm3 of aqueous solution? M= mol/dm3 M= 0.60 mol/

.1dm3 = 6 x 2 molecules of SO4= 12.0

42.400 cm3 of water is added to a solution of 200 cm3 of 0.4

mol dm-3 sodium chloride. What is the concentration of

sodium chloride in the new solution? (0.4 mol dm-3)(.200

dm3)=(.600 dm3)(M)= 0.13 mol dm-3

Solutions 443.What is the concentration of NaCl, in mol dm-3, when 10.0 cm3 of

0.300 mol dm-3 NaCl solution is added to 40.0 cm3 of 0.700 mol dm-

3 NaCl solution?

44.Which amount of the following compounds contains the least

number of ions?

1. 1 mol Al2O3

2. 2 mol CaCl2

3. 1 mol NH4OH

4. 2 mol NaCl

Solutions 443. What is the concentration of NaCl, in mol dm-3, when 10.0 cm3 of 0.300 mol

dm-3 NaCl solution is added to 40.0 cm3 of 0.700 mol dm-3 NaCl solution?

(0.700 mol dm-3)(0.8 dm3) + (0.300 mol dm-3)(0.2 dm3)= 0.62

44. Which amount of the following compounds contains the least number of

ions?

1. 1 mol Al2O3 Al2O3 → 2Al + 3O2 = 5 mol total

2. 2 mol CaCl2 CaCl2 → 1Ca + 1Cl2 = 2 + 2= 4 mol total

3. 1 mol NH4OH NH4OH → 1NH4 + 1OH = 2 mol total

4. 2 mol NaCl 2NaCl → 2Na + 1Cl2 = 4+ 2 = 6 mol total