Question

1. In water, hydrogen and oxygen combine in the mole ratio of [ ]

a) 2 : 1 b) 1 : 2 c) 1 : 1 d) 1 : 3

2. Law of conservation of mass was given by [ ]

a) Einstein b) Dalton c) Lavoisier d) Bohr

3. In CO2 carbon and oxygen combined the weight ratio of [ ]

a) 3 : 8 b) 8 : 3 c) 2 : 3 d) 3 : 2

4. Which of the following reaction is used to prepare carbon dioxide gas [ ]

a) C O CO  2 2 b) CaCO CaO CO 3 2  

c) 2 2 2 H O H O   2 d) both a and b

5. Elements are always combine in a fixed ratio of their [ ]

a) volume b) Atomic weight c) pressure d) Density

6. The product in the reaction CaCO CaO CO 3 2   [ ]

a) only CaO b) Only CO2 c) both CaO and CO2 d) CaCO3

7. 5 gm of MgCO3 on heating gives 3 gm of MgO and 2 gm of CO2 show that this equation

illustration the [ ]

a) Law of conservation of mass b) Law of constant proportion

c) both a and b d) None of the above

8. Law of constant (or) definite proportion was proposed by [ ]

a) Lavoisier b) Dalton c) Proust d) Thomson

9. What is the percentage weight of metallic element in the calcium carbonate [ ]

A0 80% b) 20% c) 40% d) 10%

10. The law of conservation of mass holds good for all of the following except [ ]

a) All chemical reactions b) Nuclear reactions

c) Endo thermic reactions d) Exothermic reactions​

Answer 1

The answer to the given questions are:

1. In water, hydrogen and oxygen combine in the mole ratio of 2:1. Since the formula of water is H₂O.
2. Law of conservation of mass was given by Dalton.
3. In CO₂, carbon and oxygen combine in the weight ratio of 3:8. Since the wight of one mole of carbon is 12 g and that of oxygen is 16 g.
4. The reaction majorly used for preparation of CO₂ gas is Option B.
5. Elements are always combine in a fixed ratio of their Atomic weight.
6. Product formed in the reaction is Both CaO and CO₂.
7. This equation illustrates the Law of conservation of mass.
8. Law of constant (or) definite proportion was proposed by Proust.
9. The percentage weight of metallic element in the calcium carbonate is 40%.
10. The law of conservation of mass holds good for all of the following except Nuclear reactions.