Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Stoichiometry”.
1. Which of the following does stoichiometry of a reaction is all about?
a) Extent of reaction
b) Heat of reaction
c) Amount of reactants and products
d) None of the mentioned
Answer: c
Clarification: By definition, Stoichiometry relates the amount of reactants and products in a reaction.
2. C2H4 + xO2 -> 2CO2 + yH2O, what is the value of x + y?
a) 2
b) 3
c) 5
d) 8
Answer: c
Clarification: The balance combustion equation is C2H4 + 3O2 -> 2CO2 + 2H2O, => x = 3, y = 2, => x + y = 5.
3. C5H12 + xO2 -> yCO2 + zH2O, what is the value of x + y*z?
a) 24
b) 38
c) 46
d) 54
Answer: b
Clarification: The balanced chemical reaction is: C5H12 + 😯2 -> 5CO2 + 6H2O, => x + y*z = 8 + 5*6 = 38.
4. wC3H6O3 + xO2 –> yCO2 + zH2O, what is the value of w + x + y + z?
a) 3
b) 6
c) 10
d) 14
Answer: d
Clarification: The balanced chemical reaction is: C3H6O3 + 3O2 –> 3CO2 + 3H2O, => w + x + y + z = 14.
5. wC3H7O4 + xO2 -> yCO2 + zH2O, what is the value of w + x + y + z?
a) 21
b) 35
c) 41
d) 47
Answer: c
Clarification: The balanced chemical reaction is: 4C3H7O4 + 11O2 -> 12CO2 + 14H2O, => w + x + y + z = 41.
6. 20 grams of CaCO3 is heated, how much calcium oxide will produce?
a) 5.6 grams
b) 11.2 grams
c) 22.4 grams
d) 44.8 grams
Answer: b
Clarification: The balance chemical reaction is CaCO3 -> CaO + CO2, moles of CaO = moles of CaCO3 = 20/100 = 0.2, => amount of CaO = 0.2*56 = 11.6 grams.
7. 56 grams of carbon monoxide is oxidized with excess oxygen, how much carbon dioxide will it produce?
a) 22 grams
b) 44 grams
c) 66 grams
d) 88 grams
Answer: d
Clarification: The balanced chemical reaction is 2CO + O2 -> 2CO2, => moles of CO2 = moles of CO = 56/28 = 2, => amount of CO2 = 2*44 = 88 grams.
8. Pentane is burnt to produce carbon dioxide 40% of which can be converted into carbon monoxide, how much Butane must be burnt to produce 176 grams of carbon monoxide?
a) 18 grams
b) 36 grams
c) 72 grams
d) 96 grams
Answer: b
Clarification: The balanced chemical reaction is C5H12 + 😯2 -> 5CO2 + 6H2O, Let the mass of pentane be x, => (x/72)*5*44*(40/100) = 176, => x = 36 grams.
9. 1 mole of glucose is burnt, how much carbon dioxide will it produce?
a) 44 grams
b) 176 grams
c) 264 grams
d) 352 grams
Answer: b
Clarification: The balanced chemical reaction is C6H12O6 + 6O2 -> 6CO2 + 6H2O, => moles of CO2 produced = 6, => amount of CO2 produced = 6*44 = 264 grams.
10. 78 grams of benzene is burnt in air, how much water will it produce?
a) 18 grams
b) 36 grams
c) 54 grams
d) 72 grams
Answer: c
Clarification: The balanced chemical reaction is C6H6 + 7.5O2 -> 6CO2 + 3H2O, => moles of water = 3*78/78 = 3, => weight of water produced = 3*18 = 54 grams.
11. xKMnO4 + yFeS + zH2SO4 -> xMnSO4 + wFe2(SO4)3 + uK2SO4 + zH2O, what is the value of x + y + z + w + u?
a) 60
b) 74
c) 85
d) 98
Answer: b
Clarification: The balanced chemical reaction is 18KMnO4 + 10FeS + 32H2SO4 -> 18MnSO4 + 5Fe2(SO4)3 + 9K2SO4 + 32H2O, => x + y + z + w + u = 74.
12. 158 grams of potassium permanganate is reacted with ferrous sulfide in the presence of hydrochloric acid, approximately how much ferric sulfate will it produce?
a) 111 grams
b) 169 grams
c) 254 grams
d) 399 grams