Question

1. Why a chemical equation is to be balanced?
2.Calculate the molar mass of a) H2SO4 b) NaCl.
(Atomic Masses H = 1U , S= 32U,O= 16U,Na= 23U, Cl=31.5U)
3. Estimate the mass percentage of sulphur in H2S
4. Write any two limitations of a balanced chemical equation.
5. Calculate the valency of chlorine in a) KCl b) KClO3.

Answer 1

Explanation:

A chemical equation should always be balanced because the law of conservation of mass states that matter can neither be created nor destroyed so in a chemical equation the total mass of reactants must be equal to the mass of products formed i.e. the total number of atoms of each element should be equal on both the

1. The molar mass of hydrogen is 1

Molar mass of sulphur (S) is 32

Molar mass of oxygen (O) is 16

Now ,

2(1)+32+4(16) = 98

Molar mass of sulphuric acid i.e. H

2

SO

4

is 98

3.2x1+32=36

36/98 x 100

36.73

4.

(1) It doesn't givr any information about the rate of the reaction.

(2) It gives not information about the by-products formed, if any.

(3) It does not tell about the actual yield of the product.

(4) It may not be kinetically feasible in reaclity.

5.given in photo