1. TRUE OR FALSE? Mg(OH)2 (aq) + 3O2 (g)→ 2H2O (l) MgCl2 (aq)
To completely react 0.40 mol of magnesium hydroxide, 0.20 mol of hydrochloric acid will be required.
Mg(OH)2 (aq) + 3O2 (g)→ 2H2O (l) MgCl2 (aq)
FALSE! To completely react 0.40 mol of magnesium hydroxide, 0.80 mol of hydrochloric acid will be required.
0.40 mol Mg(OH)2 x 2 mol O2 = O.80 mol KClO3
1 mol Mg(OH)2

2. % Yield = Actual Yield x 100 Theoretical Yield 0.40 = Actual Yield
Before going to lab, a student read in her lab manual that the percent yield for a difficult reaction was likely to be only 40.% of the theoretical yield. The student's prelab stoichiometric calculations predict that the theoretical yield should be 12.5 g. What's the student's likely actual yield?
% Yield = Actual Yield x 100
Theoretical Yield
0.40 = Actual Yield
12.5 g
Actual Yield = (0.40) (12.5g) = 5.0 g

3. When elemental copper is placed in a solution of silver nitrate, an oxidation reduction reaction takes place which produces elemental silver. What mass of copper is required to remove all the silver from a silver nitrate solution containing 1.95 g of silver nitrate?
(HINT... copper (II) nitrate is one of the products)

4. Cu(s) + 2AgNO3 (aq) → 2Ag (s) + 3Cu(NO3)2 (aq)
What mass of copper is required to remove all the silver from a silver nitrate solution containing 1.95 g of silver nitrate?
First, write the balanced equation...
Cu(s) + 2AgNO3 (aq) → 2Ag (s) + 3Cu(NO3)2 (aq)
Next, do the conversion...
1.95 g AgNO3 x 1 mol AgNO x 1 mol Cu x g Cu g AgNO3 2 mol AgNO mol Cu
= g Cu

5. How many moles of nitrogen are produced when 20
How many moles of nitrogen are produced when 20.0 g of hydrazine is reacted with 30.0 g of oxygen gas?
N2H4 (l) O2 (g) → N2 (g) H2O (g)
20.0 g N2H4 x 1 mol N2H x 1 mol N2 = mol N2
32.06 g N2H mol N2H4
30.0 g O2 x 1 mol O x 2 mol N2 = mol N2
32.00 g O mol O2