Questions on Mass Ratio Calculation
Multiple-Choice Questions: Mass Ratio Calculation
1. What is a mass ratio in chemistry?
A) The number of atoms in a molecule
B) The ratio of molar masses of elements in a compound
C) The weight of one element
D) The energy released in a reaction
E) The amount of light absorbed by a substance
2. In H₂O, what is the mass ratio of hydrogen to oxygen?
A) 1:1
B) 2:16
C) 2:8
D) 1:8
E) 2:1
3. The molar mass of carbon is 12 g/mol and of oxygen is 16 g/mol. What is the mass ratio in CO₂?
A) 12:16
B) 12:32
C) 32:12
D) 6:8
E) 24:16
4. What is the total mass of CO₂ if 12 g of carbon reacts with 32 g of oxygen?
A) 32 g
B) 12 g
C) 20 g
D) 44 g
E) 40 g
5. What is the mass ratio of sodium to chlorine in NaCl (Na = 23, Cl = 35.5)?
A) 1:1
B) 23:35.5
C) 35.5:23
D) 2:3
E) 46:71
6. What is the mass ratio of magnesium to oxygen in MgO (Mg = 24, O = 16)?
A) 24:16
B) 16:24
C) 12:8
D) 1:1
E) 2:3
7. A compound is made of 40 g of calcium and 60 g of chlorine. What is the mass ratio of Ca to Cl?
A) 2:3
B) 3:2
C) 2:5
D) 4:6
E) 1:1.5
8. What is the reduced mass ratio of 10 g of element A to 40 g of element B?
A) 1:2
B) 1:4
C) 2:1
D) 1:3
E) 4:1
9. A compound contains 20 g of hydrogen and 160 g of oxygen. What is the mass ratio?
A) 2:16
B) 1:8
C) 4:32
D) 10:80
E) 2:8
10. What is the mass ratio of nitrogen to hydrogen in NH₃ (N = 14, H = 1)?
A) 1:1
B) 14:3
C) 3:14
D) 7:3
E) 3:1
11. In SO₂ (S = 32, O = 16), what is the mass ratio of sulfur to oxygen?
A) 16:32
B) 32:32
C) 32:16
D) 32:64
E) 1:2
12. A student mixes 5 g of A with 15 g of B. What is the mass ratio of A to B?
A) 3:1
B) 1:3
C) 2:3
D) 5:10
E) 1:2
13. A compound contains 60% element X and 40% element Y by mass. What is the mass ratio X:Y?
A) 2:3
B) 3:2
C) 1:1
D) 60:40
E) 3:5
14. If 12 g of element C combines with 36 g of element D, what is the mass ratio of C to D?
A) 1:2
B) 1:3
C) 2:3
D) 1:1
E) 3:1
15. In CaCO₃ (Ca = 40, C = 12, O = 16), what is the mass ratio of Ca:C:O?
A) 40:12:48
B) 12:48:40
C) 48:40:12
D) 40:24:12
E) 1:1:1
16. A sample has 7 g of lithium and 56 g of iodine. What is the mass ratio of Li to I?
A) 1:8
B) 7:56
C) 1:7
D) 56:7
E) 8:1
17. What is the mass ratio of potassium to bromine in KBr (K = 39, Br = 80)?
A) 39:80
B) 80:39
C) 1:2
D) 40:80
E) 39:78
18. In Al₂O₃ (Al = 27, O = 16), what is the mass ratio of aluminum to oxygen?
A) 54:48
B) 27:48
C) 27:16
D) 2:3
E) 3:2
19. Which ratio is equivalent to 1:4?
A) 2:8
B) 4:1
C) 10:20
D) 3:9
E) 2:6
20. What is the ratio of hydrogen to oxygen in H₂O₂? (H = 1, O = 16)
A) 1:16
B) 2:32
C) 2:16
D) 1:8
E) 2:8
- Questions on Law of Conservation of Mass
- Questions on Law of Multiple Proportions
- Questions on Law of Definite Proportions
Answer Key with Explanations
1. B – Mass ratio is the proportion by mass of elements in a compound.
2. D – 2g H : 16g O = 1:8
3. B – 12g C : 32g O = 12:32
4. D – Total = 12 + 32 = 44 g
5. B – Na:Cl = 23:35.5
6. A – Mg:O = 24:16
7. A – 40:60 reduces to 2:3
8. B – 10:40 = 1:4
9. B – 20:160 = 1:8
10. B – N:H = 14:3
11. D – S:O = 32:32 = 32:64 (since 2 O atoms)
12. B – 5:15 = 1:3
13. B – 60:40 = 3:2
14. B – 12:36 = 1:3
15. A – Ca = 40, C = 12, O₃ = 16×3 = 48 → 40:12:48
16. C – 7:56 = 1:8
17. A – K:Br = 39:80
18. A – Al₂ = 54, O₃ = 48 → 54:48
19. A – 2:8 = 1:4
20. C – H₂ = 2, O₂ = 32 → 2:32 = 1:16
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