Use of Significant Figures

Question 1

Decimal Places & Significant Figures - What should you use the same number of d.p or s.f. as?

Answer 1

as used in the question

Question 2

Decimal Places & Significant Figures - What should measurements / data in a set should all be given to the same number of?

Answer 2

the same no. of d.p or s.f.

Question 3

Decimal Places & Significant Figures - Example:

10.25, 10.50, 10.75, 11.00

Calculate the mean

Answer 3

10.63

Question 4

Rounding - What should you not round?

Answer 4

the same value twice

Question 5

Rounding - Example:

8. 2469 -> 8.25 -> 8.3
9. 3 is wrong

Answer 5

another example:

4.99 x 10^5 (3sf) -> (2sf) 5.0 x 10^5

Question 6

Rounding - Another example:

Answer 6

3.0 x 10^-6 does not equal 3 x 10^-6

Question 7

Adding & Subtracting Decimals - What should you keep?

Answer 7

all of the decimal places

Question 8

Adding & Subtracting Decimals - Example:

6.549, 4.12, 2.1

Add them all up together

Answer 8

12.769

Question 9

Adding & Subtracting Decimals - Example:

Calculate the mean of :

6.549 + 4.12 + 2.1 = 12.769

Answer 9

12.768 / 3 = 4.3 (1.d.p)

Question 10

Multiplying & Dividing Decimals - When multiplying or dividing decimals, what must you give the answer?

Answer 10

to the lowest number of d.p / s.f. used in the calculation

Question 11

Multiplying & Dividing Decimals - What should the calculated results only be reported to?

Answer 11

to the limits of the least accurate measurement

Question 12

Multiplying & Dividing Decimals - Example:

Mass (g) - 0.086

Rate of CO2 produced - 0.19

Rate of CO2 produced per gram per min - 2.20930233 -» is this right or do you need to round it to 2.d.p?

Answer 12

it is wrong, the right answer is 2.21