NEET Chemistry: Laws of chemical combination Practice Questions
15 free multiple-choice questions on Laws of chemical combination (Some Basic Concepts in Chemistry) for NEET Chemistry, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. Which law of chemical combination states that mass is neither created nor destroyed in a chemical reaction?
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Correct answer: D — Law of Conservation of Mass
The Law of Conservation of Mass states that the total mass of reactants must equal the total mass of products in a chemical reaction.
Q2. In the reaction between two elements A and B to form a compound AB, if 10 grams of element A react completely with 15 grams of element B, the empirical formula of the compound formed is:
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Correct answer: C — A2B
The ratio of masses is A:B = 10:15 = 2:3. Thus, the empirical formula is AB2B3, or based on the simplest ratio, 2A:3B, meaning the formula is A2B3.
Q3. The Law of Definite Proportions (or Constant Composition) implies that:
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Correct answer: D — Elements always combine in a fixed ratio by weight.
The Law of Definite Proportions states that a chemical compound always contains the same elements in the same proportion by mass, regardless of the source.
Q4. If two elements A and B combine to form two different compounds, AB and AC, the ratio of masses of B that combine with a fixed mass of A is:
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Correct answer: D — Directly proportional to their atomic masses.
This relates to the Law of Multiple Proportions, which states that when two elements combine to form two or more different compounds, the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.
Q5. The Law of Definite Proportions is also known as which law?
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Correct answer: D — Law of Constant Proportions
The Law of Definite Proportions states that a chemical compound always contains the same elements in the same proportion by mass. It is also often referred to as the Law of Constant Proportions.
Q6. The Law of Constant Proportions states that:
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Correct answer: C — A given element always combines with another element in a fixed ratio by mass.
The Law of Constant Proportions (or definite proportions) states that the elements in a chemical compound are always combined in a fixed ratio by mass.
Q7. According to the Law of Conservation of Mass, if 10 grams of substance X react with 15 grams of substance Y to form a compound, what is the total mass of the product formed?
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Correct answer: D — 25 grams
The Law of Conservation of Mass dictates that the total mass of reactants must equal the total mass of products. Total mass = 10g + 15g = 25g.
Q8. Which of the following laws is directly related to the conservation of mass in a chemical reaction?
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Correct answer: D — Law of Conservation of Mass
The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction.
Q9. The Law of Multiple Proportions states that if two elements combine to form two or more different compounds, the masses of one element that combine with a fixed mass of the other element are in a ratio of small whole numbers. This law is most closely related to:
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Correct answer: D — Definite Proportions
The Law of Multiple Proportions specifically deals with the relative masses of one element when combined with a fixed mass of another element in different compounds.
Q10. In a chemical reaction, the total mass of the reactants must be equal to the total mass of the products. This principle is known as:
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Correct answer: C — Law of Conservation of Mass
The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of reactants equals the total mass of products.
Q11. In a chemical combination, the ratio of the masses of two elements that combine to form a fixed compound is known as:
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Correct answer: C — Mass ratio
The fixed ratio of masses of two elements that combine is the basis for the Law of Constant Proportions.
Q12. If 10 grams of Carbon combine with 10 grams of Oxygen to form a compound, the total mass of the product formed is:
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Correct answer: C — 20 grams
According to the Law of Conservation of Mass, the total mass of the reactants must equal the total mass of the products (10g C + 10g O = 20g product).
Q13. When two elements A and B combine to form two different compounds, AB₂ and A₂B, the ratio of the masses of B that combine with a fixed mass of A is:
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Correct answer: B — 2:1
According to the Law of Multiple Proportions, if A combines with B to form AB₂ and A₂B, the ratio of masses of B is 1:2 (since the mass of A is fixed).
Q14. Which of the following statements correctly describes the Law of Conservation of Mass?
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Correct answer: C — Mass is conserved in any chemical reaction.
The fundamental statement of the Law of Conservation of Mass is that mass is conserved during a chemical reaction.
Q15. Which of the following laws states that mass is neither created nor destroyed in a chemical reaction?
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Correct answer: C — Law of Conservation of Mass
The Law of Conservation of Mass states that the total mass of reactants must equal the total mass of products in any chemical reaction, confirming that mass is conserved.
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