# Review for Chapters 4 and 5

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Review for Chapters 4 and 5

1. You need 65.0 g of aluminum for an experiment. How many atoms of aluminum is this?

2. There are 3.20 ´ 1022 atoms of copper in the outer shell of pennies. How many grams of copper is this?

3. Find the molar masses for the following:

a. Mg3(PO4)2

b. CH3CO2H

c. Calcium Carbonate

4. What's the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen and 29.0% oxygen? If the molar mass of the molecule is 110 grams/mole, what is the molecular formula?

5. Sodium chloride can be prepared by the reaction of sodium metal and chlorine gas.

__Na + __Cl2 à __NaCl

a.  What is the limiting reactant if 6.70 grams of Na react with 3.20 grams of Cl2?

b.  How many grams of NaCl are produced?

6. Nickel replaces silver from silver nitrate in solution according to the following equation:

2 AgNO3 + Ni à 2 Ag + Ni(NO3)2

a. If you have 22.9 g of Ni and 112 g of AgNO3, what is the limiting reactant?

b. What mass of nickel(II) nitrate would be produced given the quantities above?

7. Consider the following reaction:

2Na3PO4 + 3CaCl2 ® 6NaCl + Ca3(PO4)2

100. g Na3PO4 and 100. g CaCl2 are combined and allowed to react completely.

a.  What is the limiting reagent?

b.  Use an ICE chart to determine the mass of all compounds once the reaction has finished.

c.  What is the theoretical yield of Ca3(PO4)2?

d.  If only 72.4 g of Ca3(PO4)2 were actually made, what is the percent yield of the reaction?

8. X2CO3 + 2HCl ----> 2XCl + CO2 + H2O

2.76 grams of X2CO3 was treated with an excess of dilute hydrochloric acid. 0.878 grams of carbon dioxide were produced. What is element X?

9. In a very violent reaction called a thermite reaction, aluminum metal reacts with iron(II) oxide to from iron metal and aluminum oxide according to the following equation:

Fe2O3 + 2 Al à 2 Fe + Al2O3

a.  What mass of Al will react with 150 g of Fe2O3?

b.  If 0.905 mol of Al2O3 is produced in the reaction, what mass of Fe is produced?

c.  How many moles of Fe2O3 will react with 99.0 g of Al?

10. Lead(II)nitrate reacts with potassium iodide to produce lead(II) iodide and potassium nitrate.

a. Write the balanced chemical equation for this reaction.

b. If 1.23 g of lead(II) nitrate are consumed, what is the mass of the potassium nitrate produced?

11. Carbon tetrachloride, CCl4, is a solvent that was once used in large quantities in dry cleaning. Because it is a dense liquid that does not burn, it was also used in fire extinguishers. Unfortunately, its use has been discontinued because it was found to be a carcinogen. It was manufactured by the following reaction:

CS2 + 3 Cl2 à CCl4 + S2Cl2

a. What is the percent yield of CCl4 if 719 g is produced from the reaction of 410 g of CS2?

b. If 67.5 g of Cl2 are used in the reaction and 39.5 g of S2Cl2 is produced, what is the percent yield?

12. Calcium carbonate is decomposed by heating to form calcium oxide and carbon dioxide gas.

a. Write the balanced chemical equation.

b. What is the percent yield of this reaction if 24.8 g of CaCO3 is heated to give 13.1 g of CaO?

13. Predict the products and balance the equation:

a. C2H4 + O2 à

b. K + Mg(NO3)2 à

c. N2O4 à

d. Ca + O2 à

e. Li2CO3 + FeBr2 à