Question

count the significant digits in each of these measurements: measurement number of significant digits 0.004200 j 1.8×10⁻³ ml - 5.0×10⁻³ kj/mol 84400. kg

Explanation:

Step1: Recall significant - digit rules for 0.004200 J

Leading zeros are not significant. Trailing zeros after a non - zero digit and after a decimal point are significant. So, 4, 2, 0, 0 are significant.

Step2: Recall significant - digit rules for 1.8×10⁻³ mL

In scientific notation, all digits in the coefficient (1.8) are significant.

Step3: Recall significant - digit rules for - 5.0×10⁻³ kJ/mol

In scientific notation, all digits in the coefficient (5.0) are significant.

Step4: Recall significant - digit rules for 84400. kg

The decimal point indicates that the trailing zero is significant. So, 8, 4, 4, 0, 0 are significant.

Answer:

4
2
2
5