Unit Assessment of Lessons: Stoichiometry ALL

Goal 4.6.1a: I can use a balanced chemical equation to identify mole-to-mole ratios.

Goal 4.6.1b: I can use mole-to-mole ratios to calculate molar relationships in a chemical reaction.

Goal 4.6.2a: I can use a balanced chemical equation to calculate mole-to-mass relationships in a chemical reaction.

Goal 4.6.2b: I can use a balanced chemical equation to calculate mass-to-mass relationships in a chemical reaction.

Goal 4.6.3a: I can calculate and determine the limiting reactant of a chemical reaction.

Goal 4.6.3b: I can calculate the percent yield of a chemical reaction.

Goal 4.7.1a: I can calculate and determine the Molarity of reactants/products in a chemical reaction.

Goal 4.7.2a: I can use stoichiometry to determine mass of substances (g), volume of gases at STP (L), and representative particles of reactants/products from balanced chemical equations.

Multiple Choice

Identify the choice that best completes the statement or answers the question.

____ 1. If 1 egg and ⅓ cup oil are needed for each bag of brownie mix, how many bags of brownie mix do you need if you want to use 3 eggs and 1 cup of oil?

a. 1

b. 2

c. 3

d. 4

____ 2. What is the first step in most stoichiometry problems?

a. a fully balanced chemical equation

b. convert given quantities to moles

c. convert given quantities to volumes

d. convert given quantities to masses

____ 3. In the reaction 2CO(g)  +  O2(g)  →  2CO2(g), what is the ratio of moles of oxygen used to moles of CO2 produced?

a. 1:1

b. 2:1

c. 2:2

d. 1:2

____ 4. When two substances react to form products, the reactant which is used up is called the:

a. determining reagent.

b. limiting reagent.

c. excess reagent.

d. catalytic reagent.

____ 5. Which of the following is true about limiting and excess reagents?

a. The amount of product obtained is determined by the limiting reagent.

b. A balanced equation is not necessary to determine which reactant is the limiting reagent.

c. Both reagents are left over after the reaction is complete.

d. The reactant that has the smallest given mass is always the limiting reagent.

____ 6. Which type of stoichiometric calculation does not require the use of the Molar Mass?

a. Mass-to-mass problems

b. Mass-to-volume problems

c. Mass-to-particle problems

d. Volume-to-volume problems

____ 7. Which of the following is an incorrect interpretation of the following balanced chemical equation: 2S(s)  +  3O2(g)  →  2SO3(g)

a. 2 atoms S + 3 molecules O2 → 2 molecules SO3

b. 2g S  +  3g O2  →  2g SO3

c. 2mol S  +  3mol O2  →  2mol SO3

d. 5mol reactants → 2mol products

____ 8. How many moles of Al are needed to react completely with 1.2mol FeO according to the following reaction?         2Al(s) + 3FeO(s) → 3Fe(s) + Al2O3(s)

a. 1.2mol Al

b. 0.8mol Al

c. 1.6mol Al

d. 2.4mol Al

____ 9. How many grams of H3PO4 are produced when 10.0mol H2O react with excess P4O10 according to the following reaction?         P4O10(s) +  6H2O(l)  →  4H3PO4(aq)

a. 1.22g H3PO4

b. 6.7g H3PO4

c. 147g H3PO4

d. 653g H3PO4

____ 10. Mercury can be obtained by reacting mercury (II) sulfide with calcium oxide. According to the following reaction, how many grams of calcium oxide are needed to produce 36.0g Hg?

4HgS(s) + 4CaO(s) → 4Hg(l) + 3CaS(s) + CaSO4

a. 1.80g CaO

b. 7.56g CaO

c. 10.1g CaO

d. 13.4g CaO

____ 11. Metallic copper is formed when aluminum reacts with copper (II) sulfate. How many grams of metallic copper can be obtained when 54.0g Al react with 319g of CuSO4 according to the following reaction?         Al + 3CuSO4 → Al2(SO4)3 + 3Cu

a. 21.2g Cu

b. 127g Cu

c. 162g Cu

d. 381g Cu

____ 12. What is the maximum number of grams of PH3 that can be formed when 6.2g phosphorus reacts with 4.0g hydrogen to form PH3 according to the following reaction?

P4(g) +  6H2(g) →  4PH3(g)

a. 0.43g PH3

b. 6.8g PH3

c. 270g PH3

d. 45g PH3

____ 13. In a particular reaction between copper metal and silver nitrate, 12.7g Cu produced 38.1g Ag according to the following reaction. What is the percent yield of silver in this reaction?

Cu + 2AgNO3 → Cu(NO3)2 + 2Ag

a. 56.7%

b. 77.3%

c. 88.2%

d. 176%

____ 14. How many mL of 3.28M H3PO4 are needed to neutralize 27.5mL of a 0.985M LiOH solution according to the following reaction?  3LiOH(aq)  +  H3PO4(aq)  →  Li3PO4(aq)  +  3HOH(l)

a. 30.5mL H3PO4

b. 0.00275mL H3PO4

c. 2.75mL H3PO4

d. 0.0305mL H3PO4

____ 15. Calculate the number of grams of KCl that can be produced from 29.3g HCl and 325mL of 3.50M KOH according to the following reaction? KOH(aq)  +  HCl(aq)  →  KCl(aq)  +  HOH(l)

a. 84.8g KCl

b. 59.9g KCl

c. 45.1g KCl

d. 63.8g KCl

____ 16. At STP, how many liters of oxygen are required to react completely with 3.6L of hydrogen to form water according to the following reaction? 2H2(g)  +  O2(g)  →  2H2O(g)

a. 1.8L O2

b. 3.6L O2

c. 2.0L O2

d. 2.4L O2

____ 17. How many liters of hydrogen gas are needed to react with CS2 to produce 2.50L of CH4 at STP according to the following reaction?  CS2(l)  +  4H2(g)  →  CH4(g)  +  2H2S(g)

a. 2.50L H2

b. 5.00L H2

c. 7.50L H2

d. 10.0L H2

____ 18. Which of the following statements about the reaction below is true?

3NaHCO3(aq)  +  C6H8O7(aq) → 3CO2(g)  +  3H2O(l)  +  Na3C6H5O7(aq)

a. 22.4L of CO2(g) are produced for every Liter of Na3C6H5O7(aq) reacted.

b. 1mol of water is produced for every mole of carbon dioxide produced.

c. 6.022x1023 molecules of Na3C6H5O7(aq) are produced for every mole of NaHCO3(aq) used.

d. 54g of water are produced for every mole of NaHCO3(aq) produced.

____ 19. How many Liters of NH3 are needed to react completely with 30.0L of NO, at STP, according to the following reaction? 4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(g)

a. 5.0L

b. 20.0L

c. 7.5L

d. 120.0L

____ 20. When 0.1mol of calcium reacts with 880g of water, 2.24L of hydrogen gas form, at STP. How would the amount of hydrogen produced change if the volume of water was decreased to 440mL (440g) according to the following reaction?

Ca(s)  +  2H2O(l)  →  Ca(OH)2(aq)  +  H2(g)

a. Only one half the volume of hydrogen would be produced.

b. The volume of hydrogen produced would be the same.

c. The volume of hydrogen produced would double.

d. No hydrogen would be produced.

____ 21. How many Liters of NH3, at STP, will react with 5.3g O2 to form NO2 and water according to the following reaction?                 4NH3(g) + 7O2(g) → 4NO2(g) + 6H2O(g)

a. 0.00423L

b. 2.12L

c. 3.03L

d. 6.49L

____ 22. Methane and hydrogen sulfide form when hydrogen reacts with carbon disulfide. Identify the excess reagent and calculate how much remains after 36L of H2 reacts with 12L of CS2 according to the following reaction. 4H2(g) + CS2(g) → CH4(g) + 2H2S(g)

a. 3L CS2

b. 6L CS2

c. 9L CS2

d. 12L H2