Question

To how many significant figures should each answer be rounded? a) (6.62610^-34 Js)(2.997910^8 m/s) / 4.07010^-7 m = 4.880610663391*10^-19 J(unrounded)b) (6.02210^23 atoms/mol)(0.589 g) / 20.18 g/mol = 1.75810^22 atoms (unrounded)

Answer 1

a) after rounding: 4 significant figures.

b) after rounding: 3 significant figures.

Explanation:

Significant figures are the number of needed place values for accuracy. The product or quotient of numbers with significant figures must be rounded to the least amount present within the problem.

a) (6.62610^-34 Js)(2.997910^8 m/s) / 4.07010^-7 m = 4.880610663391*10^-19 J

4.880610663391*10^-19 rounds to 4.880 * 10^-19 since the least number of significant digits is 4 within the problem.

b) (6.02210^23 atoms/mol)(0.589 g) / 20.18 g/mol = 1.75810^22 atoms

1.75810^22 rounds to 1.76 *10^22 since the least number of significant digits within the problem is 3.