Question

Question 1.31 How many significant figures should be present in the answer of the following calculations?

(i) [ 0.02856 x 298.15 x 0.112 ] / 0.5785

(ii) 5 × 5.364

(iii) 0.0125 + 0.7864 + 0.0215

Class XI Some Basic Concepts of Chemistry Page 24

Answer 1

1. Least precise no. of calculation=0.12. No.of significant figures in Least precise no. Will be 3. 2.Least precise no. of calculation=5.364. No.of significant figures in least precise no. Will be 4. 3.Least precise no. of calculation= 0.0125+0.7864+0.0215. No.of significant no.=4 as least no.of decimal places in each term is also 4.

Answer 2

(i)concept : In multiplication and division, the significant figure will be same as significant figure of the least precise term .

here, we see that the least precise term 0.112 has 3 significant figure . Hence, the answer should have three significant figure .

(ii) concept : In multiplication, we have see maximum number of significant figure then resultant have also maximum significant figure .

here we see that 5.364 has 4 significant figures .Hence, the answer should have 4 significant figures .


(iii) in addition, the answer can't have more digits to the decimal point than either of original members . Hence, answer should have 4 significant figures.