1.

Express the following sum to appropriate number of significant figures :a. 2.3 × 103 mL + 4.22 × 104mL + 9.04 × 103mL + 8.71 × 105mL;b. 319.5 g – 20460 g – 0.0639 g – 45.642 g – 4.173 g

Answer»

To perform addition/subtraction operation, first the numbers are written in such a way that they have the same exponent.

The coefficients are then added/subtracted.

(a). (0.23 × 104mL) + (4.22 × 104mL) +(0.904 × 104mL) + (87.1 × 104mL)

= (0.23 + 4.22 + 0.904 + 87.1) × 104mL 

= 92.454 × 104mL 

= 9.2454 × 105 

= 9.2 × 105mL

(b). 319.5 g – 20460 g – 0.0639 g – 45.642 g – 4.173 g

= – 20190.3789 g 

= – 20190 g

∴ Sum to appropriate number of significant figures = 9.2 × 105mL

Sum to appropriate number of significant figures = – 20190 g

[Note : In addition and subtraction, the final answer is rounded to the minimum number of decimal point of the number taking part in calculation. If there is no decimal point, then the final answer will have no decimal point.]



Discussion

No Comment Found