Law of Constant Proportions

Q.

The molecular formula of calcium chloride is ${\mathrm{CaCl}}_2$ . What is the molecular weight of this drug?

Q.

Calculate the molecular mass of C₂H₄.

Q. A scientist collected a sample of ${\text{CO}}_2$ gas. The total mass of carbon in the sample is 36 g. What is the mass of oxygen in the sample?

(Atomic mass of oxygen is 16 u and that of carbon is 12 u)

1. 64 g
2. 96 g
3. 108 g
4. 128 g

Q.

An astronaut gets thirsty on the moon. So, he makes water by mixing hydrogen and oxygen. Will the mass ratio of hydrogen to oxygen present in the water that he made on moon will be same as that on the earth?

1. On moon the water will have heavier mass than on earth

2. It will be different.

3. It will be the same.

4. On moon the water will have lighter mass than on earth.

Q.

Calculate the number of moles of methane in $0.80g$ of methane.

Q. List down the postulates of Dalton's atomic theory.

Q.

A sample containing 85 g of NH₃ is decomposed into nitrogen and hydrogen. The total amount of nitrogen and hydrogen present in 85 g of the sample respectively are:

1. 71, 14

2. 70, 15

3. 15, 70

4. 56, 20