Laws of Chemical Combination — Homi Bhabha Exam Chemistry MCQs with Solutions
Free Homi Bhabha Exam Chemistry Laws of Chemical Combination MCQs with step-by-step solutions (5 questions). Part of Atoms, Molecules & Structure. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Laws of Chemical Combination · medium · theory
The law of conservation of mass states that in a chemical reaction, mass is:
A. neither created nor destroyed ✓ Correct
B. converted into energy
C. always decreased
D. always increased
Solution: The total mass of the reactants equals the total mass of the products.
Q2 — Laws of Chemical Combination · hard · theory
The law of constant (definite) proportions states that a pure chemical compound always contains the same elements combined in a:
A. ratio of 1:1 always
B. variable ratio by mass
C. fixed ratio by mass ✓ Correct
D. ratio that depends on temperature
Solution: A given compound always has its constituent elements in the same fixed mass ratio.
Q3 — Laws of Chemical Combination · hard · numerical
In water, hydrogen and oxygen are always combined in the mass ratio 1 : 8. The mass of oxygen that combines with 3 g of hydrogen is:
A. 3 g
B. 24 g ✓ Correct
C. 11 g
D. 8 g
Solution: Ratio 1 : 8 means $3 \times 8 = 24$ g of oxygen combines with 3 g of hydrogen.
Q4 — Laws of Chemical Combination · hard · numerical
When 12 g of carbon burns completely in 32 g of oxygen, the mass of carbon dioxide formed (by conservation of mass) is:
A. 20 g
B. 32 g
C. 384 g
D. 44 g ✓ Correct
Solution: Mass of products = mass of reactants $= 12 + 32 = 44$ g.
Q5 — Laws of Chemical Combination · medium · theory
The law of constant proportions was proposed by the scientist:
A. Newton
B. Rutherford
C. Bohr
D. Proust ✓ Correct
Solution: Joseph Proust put forward the law of definite (constant) proportions.