2. Math vs. Science to a mathematician: 73 = 73.0 = 73.00 = 73.000 etc
to a scientist, these numbers have a more complicated meaning

3. Numbers in Science
counts are exact and have finite number of significant figures
example: this room has 30
mathematically these # are all equal:
030 = 30 = 30. = 30.0 = =
not equal from chemistry point of view

4. dealing with large numbers of very small particles
significant figures are used for data calculations in chemistry because..
dealing with large numbers of very small particles
#’s often written to power of 10
ex: (3.26 x 10-5)

5. How do I determine the number of Significant Figures?

6. P 
 A
the easiest way to count sig figs is by using the Atlantic and Pacific Rule

7. 1st ask yourself this question:
does the number have a decimal point?
decimal point Absent start counting from
Atlantic Ocean (right) side of #
decimal point Present start counting from
Pacific Ocean (left) side of #

8. Decimal point Absent: start counting on Atlantic (right) side
start counting with first non-zero digit & count until reach end of #
5400 m
has
2 sig figs
5400
5431
5431 m
has
4 sig figs

9. Decimal point Present:
start counting on Pacific (left) side
start counting with first non-zero digit & count until reach end of # g
has
7 sig figs
has
4 sig figs km

10. after math calculations your answer may not contain enough sig figs
sometimes,
after math calculations your
answer may not contain enough
sig figs
because…
there are zeros that are not
considered significant
ex:
if calc answer is 5300, but need 3 sig figs…

11. if you want a zero to be significant draw a line above to show that it is significant

12. once in a BLUE MOON rule 5300 cm (2 sig figs) becomes:_

13. when doing calculations that involve: Multiplication and Division
final answer may only have as many sig figs as data number with least # of sig figs

14. correct answer: 4 24.56 cm x 14 cm = 2 sig figs 343.84 cm2 343.8 cm2

15. when doing calculations that involve: Addition and Subtraction
2 possibilities:
1st need to look & see if any of the data numbers have decimals present

16. 1. If ALL data # have decimals:
final answer may only have as many decimal places as data number with least number of decimal places

17. 2. If some or NO decimals present:
final answer may only have as many significant figures as data number with least number of sig figs

18. correct answer: C 422.63 cm 29.472 cm 115.9 cm + 1 decimal place
________________
a) cm
b) cm
c) cm
d) cm
correct answer: C

19. correct answer: D NO decimals 422 cm 29 cm + 115 cm a) 566.0 cm
2 sig figs
_______________
a) cm
b) cm
566 cm
d) cm
correct
answer: D