9/30/22 - Significant Figures Flashcards
Are non-zero numbers significant?
Yes, always
Are zeros between non-zero numbers significant?
Yes, always
When are trailing zeros significant?
When there is a decimal point at the end.
1.30 = 3 significant figures
2,400 = 2 significant figures
2,400. = 4 significant figures
How many sig figs are in 0.00240?
3 sig figs
How many sig figs are in 0.5078?
4 sig figs
How many sig figs are in 8,090?
3 sig figs
How many sig figs are in 0.800?
3 sig figs
How many sig figs are in 92,000. ?
5 sig figs (note the decimal point)
How many sig figs are in 3.460 x 10^-2
4 sig figs
How do you determine significant figures in addition and subtraction?
The answer has the same number of decimal places as the measurement with the fewest decimal places.
8.447 cm + 9.2 cm = 17.647. How should this be rounded for significant figures?
17.6 because 9.2 only has one decimal place.
How do you determine significant figures in multiplication and division?
The answer has the same number of significant figures as the measurement with the fewest significant figures,
9.2 cm x 6.8 cm x 0.3744 cm = 23.422464 cm^3. How should this be rounded for significant figures?
23 cm^3 because 9.2 and 6.8 have only 2 sig figs.
What are exact numbers? What do they mean for significant figures?
Exact numbers have no uncertainty. Many are unit definitions or conversions, for instance. There are 60 minutes in an hour.
They do not limit the number of sig figs in a calculation.
