Worksheet 7A  The Mole and Chemical Quantities 1) What is the molar mass of ammonium sulfate? 2) a) How many MOLECULES of nitrogen trifluoride are present in 4

Worksheet 7A  The Mole and Chemical Quantities

1) What is the molar mass of ammonium sulfate?

2) a) How many MOLECULES of nitrogen trifluoride are present in 4.50 moles of this compound?

b) How many ATOMS of fluorine are present in 4.50 moles of nitrogen trifluoride?

c) How many MOLES of nitrogen trifluoride are present in 1.24 x 10²² molecules of this compound?

d) How many grams of nitrogen trifluoride must be weighed out to get a sample of nitrogen trifluoride that contains 18.7 g of fluorine?

e) If a sample of nitrogen trifluoride contains 18.7 g of fluorine, how many grams of nitrogen does it contain?

3) Magnesium hydroxide and ammonia are formed when magnesium nitride is added to water

Mg3N2(s) + 6 H2O (1) a 3 Mg(OH)2 (s) + 2 NH3 (1)

a) How many moles of magnesium nitride are needed to produce 2.00 moles of ammonia?

b) If 6.62 grams of magnesium nitride are mixed with excess water, how many grams of magnesium hydroxide are produced?

c) If the reaction in question 3b) yields 9.10 g magnesium hydroxide, what is the percent yield?

4) For the following reaction:

CaCO3(s) + 2 HCI(aq) - CaCl2(aq) + CO2(g) + H20(1)

a) If 25.0 g CaCO3 and 0.25 mol of HCI in solution are placed in a reaction vessel, which reactant is limited?

b) How many moles of calcium chloride could be produced?

c) What is the percent yield of this reaction if 25.25 g of calcium chloride was collected?