1. 20 g of lithium hydroxide was reacted with potassium chloride:
LiOH + KCl à LiCl + KOH
(a) What is the theoretical yield of lithium chloride?
(b) If 6 g of lithium chloride was actually produced, what is the percentage yield?
2. The equation below shows the combustion of propanol:
C3H8 + 5 O2 à 3 CO2 + 4 H2O
a) If you start with 5 grams of C3H8, what is the theoretical yield of water?
b) If the percentage yield was 75%, how many grams of water will actually be made?
3. In the reaction below, the theoretical yield was 10.7 g but the actual yield was 4.5 g.
Calculate the percentage yield.
Be + 2 HCl à BeCl2 + H2
4. What is the theoretical yield of sodium oxide if you start with 20 grams of calcium oxide?
2 NaCl + CaO à CaCl2 + Na2O
5. In the reaction below:
FeBr2 + 2 KCl à FeCl2 + 2 KBr
a) What is the theoretical yield of iron (II) chloride if you start with 340 g of iron (II) bromide?
b) What is my percentage yield of iron (II) chloride if my actual yield is 40 g?
6. In the reaction below:
TiS + H2O à H2S + TiO
What is the percentage yield of titanium (II) oxide if you start with 20 g of titanium (II) sulfide and the actual yield of titanium (II) oxide is 22 g?
7. In the reaction below:
U + 3 Br2 à UBr6
What is the actual yield of uranium hexabromide if you start with 100 g of uranium and get a percentage yield of 83% ?
8. In the reaction below:
H2SO4 à H2O + SO3
If you start with 89 kg of sulfuric acid and produce 71 kg of water, what is the percentage yield?
9. If, in the reaction below 32 kg of C2H6 produces 44 kg of CO2, what is the % yield?
2C2H6 + 7O2 à 4CO2 + 6H2O
10. If, in the reaction below, 80 g of Cl2 produces 38 g of CCl4 what is the % yield?
CS2 + 3Cl2 à CCl4 + S2Cl2
11. If, in the reaction below, 49 g of Fe3O4 produces a 78.25 % yield of Fe. How many grams are produced?
Fe3O4 + 4H2 à 3Fe + 4H2O
12. If, in the reaction below, 40 tonnes of H2O produces 6.7 tonnes of HF what is the % yield?
CH3COF + H2O à CH3COOH + HF
13. Calculate the atom economy for the production of lithium chloride assuming that all the reactants are converted into products.
LiOH + KCl à LiCl + KOH
14. Calculate the atom economy for the production of titanium oxide assuming that all the reactants are converted into products.
TiS + H2O à H2S + TiO
15. Calculate the atom economy for the production sulphur trioxide assuming that all thereactants are converted into products.
H2SO4 à H2O + SO3
16. Which reaction below has the highest atom economy for producing water?
2C2H6 + 7O2 à 4CO2 + 6H2O
C3H6 + 4½O2 à 3CO2 + 3H2O
17. Sulphur trioxide can be prepared in the laboratory by the reaction of sulphur dioxide with oxygen.
2SO2(g) + O2(g) 2SO3(g)
The sulphur dioxide and oxygen gases are dried by bubbling them through concentrated sulphuric acid. The reaction mixture is passed over heated vanadium(V) oxide.
Sulphur trioxide has a melting point of 17 °C. It is collected as a white crystalline solid.
Under certain conditions, 43·2 tonnes of sulphur trioxide are produced in the reaction of 51·2 tonnes of sulphur dioxide with excess oxygen.
Calculate the percentage yield of sulphur trioxide.
18. From the 1990s, ibuprofen has been synthesised by a three step process. The equation below shows the fi nal step of the synthesis.
What is the atom economy of this step?
19. Ethane-1,2-diol is produced in industry by reacting glycerol with hydrogen. Excess hydrogen reacts with 27·6 kg of glycerol to produce 13·4 kg of ethane-1,2-diol.
Calculate the percentage yield of ethane-1,2-diol.
