Chemical Engineering

Stoichiometry

Question 1
Marks : +2 | -2
Pass Ratio : 100%
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?
18 grams
36 grams
72 grams
96 grams
Explanation:
The balanced chemical reaction is C5H12 + 8O2 -> 5CO2 + 6H2O, Let the mass of pentane be x, => (x/72)*5*44*(40/100) = 176, => x = 36 grams.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Which of the following does stoichiometry of a reaction is all about?
Extent of reaction
Heat of reaction
Amount of reactants and products
None of the mentioned
Explanation:
By definition, Stoichiometry relates the amount of reactants and products in a reaction.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
wC3H6O3 + xO2 –> yCO2 + zH2O, what is the value of w + x + y + z?
3
6
10
14
Explanation:
The balanced chemical reaction is: C3H6O3 + 3O2 –> 3CO2 + 3H2O, => w + x + y + z = 14.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
1 mole of glucose is burnt, how much carbon dioxide will it produce?
44 grams
176 grams
264 grams
352 grams
Explanation:
The balanced chemical reaction is C6H12O6 + 6O2 -> 6CO2 + 6H2O, => moles of CO2 produced = 6, => amount of CO2 produced = 6*44 = 264 grams.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
78 grams of benzene is burnt in air, how much water will it produce?
18 grams
36 grams
54 grams
72 grams
Explanation:
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.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
56 grams of carbon monoxide is oxidized with excess oxygen, how much carbon dioxide will it produce?
22 grams
44 grams
66 grams
88 grams
Explanation:
The balanced chemical reaction is 2CO + O2 -> 2CO2, => moles of CO2 = moles of CO = 56/28 = 2, => amount of CO2 = 2*44 = 88 grams.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
C5H12 + xO2 -> yCO2 + zH2O, what is the value of x + y*z?
24
38
46
54
Explanation:
The balanced chemical reaction is: C5H12 + 8O2 -> 5CO2 + 6H2O, => x + y*z = 8 + 5*6 = 38.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
C2H4 + xO2 -> 2CO2 + yH2O, what is the value of x + y?
2
3
5
8
Explanation:
The balance combustion equation is C2H4 + 3O2 -> 2CO2 + 2H2O, => x = 3, y = 2, => x + y = 5.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
20 grams of CaCO3 is heated, how much calcium oxide will produce?
5.6 grams
11.2 grams
22.4 grams
44.8 grams
Explanation:
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.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
wC3H7O4 + xO2 -> yCO2 + zH2O, what is the value of w + x + y + z?
21
35
41
47
Explanation:
The balanced chemical reaction is: 4C3H7O4 + 11O2 -> 12CO2 + 14H2O, => w + x + y + z = 41.