Theme 2 - Writing Significant Figures

Question 1

What are the rules regarding non-zero digits in significant figures?

Answer 1

Non-zero digits are always significant

Example: In 1.38 g, all numbers are significant.

Question 2

How are zeros between significant digits treated in significant figures?

Answer 2

Any zeros between two significant digits are significant

Example: In 203 mm, all three digits are significant.

Question 3

When are trailing zeros considered significant?

Answer 3

A final zero or trailing zeros are ‘significant’ ONLY in decimal notation

Example: In 0.0012, there are 4 significant figures.

Question 4

What is the rule for significant figures in multiplication/division?

Answer 4

The result should have the same number of significant figures as the value with the fewest significant figures

Example: 15.20 (4 s.f.) x 1.25 (3 s.f.) = 19.0 (3 s.f.)

Question 5

What is the rule for significant figures in addition/subtraction?

Answer 5

The result should have the same number of decimal places as the value with the fewest decimal places

Example: 1,992.123 + 34.12 = 2026.24 (limited to two decimal places)

Question 6

What happens to the number of significant figures in the final answer?

Answer 6

The number of significant figures in your answer is limited to the measurement with lowest significant figures

Example: A thermometer can show only 3 significant figures, so no answer in temperature should have decimal places.

Question 7

Fill in the blank: A final zero or trailing zeros are ‘significant’ ONLY in _______.

Answer 7

[decimal notation]

Question 8

True or False: In calculations, the significant figures of the result can exceed those of the least precise measurement.

Answer 8

False

Question 9

Fill in the blank: When adding numbers, the result should have the same number of _______ as the value with the fewest decimal places.

Answer 9

[decimal places]