Identify the correct statements. (1.) In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always 8 1: . (2.) If 9 g of water is decomposed, 1 g of hydrogen and 8 g of oxygen are always obtained. (3.) In ammonia, nitrogen and hydrogen are always present in the ratio 3 1: 4 by mass. (4.) Many compounds are composed of two or more elements and each such compound has the same elements in the same proportions. (a) 1 and 3 (b) 1,2 and 3 (c) 2 and 4 (d) All of these
Answers
Answer:
right answer is (D)
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Answer:
Statements 2 and 4 are correct and statements 1 and 3 are incorrect.
Therefore, option c) 2 and 4 is the correct option.
Explanation:
Statement 1: In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always 8:1.
As we know,
- The mass of two hydrogen atoms in H₂O = 2 amu
- The mass of one oxygen atom in H₂O = 16 amu
Therefore,
- The ratio of hydrogen and oxygen by mass = 2:16 = 1:8
- So, statement 1 is incorrect.
Statement 2: If 9 g of water is decomposed, 1 g of hydrogen and 8 g of oxygen are always obtained.
As we know,
- The hydrogen and oxygen combine in a 1:8 ratio, respectively to form water.
- So if 9g of water decomposed, we will get 1g of hydrogen and 8g of oxygen.
- So, statement 2 is correct.
Statement 3: In ammonia, nitrogen and hydrogen are always present in the ratio 3:14 by mass.
As we know,
- In NH3, the mass of 1 nitrogen = 14 amu
- And the mass of 3 hydrogen = 3 amu
Therefore,
- The ratio of nitrogen and hydrogen by mass is 14:3
- So, statement 3 is incorrect.
Statement 4: Many compounds are composed of two or more elements and each such compound has the same elements in the same proportions.
As we know,
- The compounds are made up of two or more elements, combined in a fixed ratio by mass.
- E.g., H₂O, CO₂ etc.
- So, statement 4 is correct.
Result: Statements 2 and 4 are correct and statements 1 and 3 are incorrect.