Transcript Significant Figures

Significant Figures
• Be able to identify the number of
significant figures that an number has.
Certainty in Measurement
• Rules of significant digits determine
how many digits should be written for
a measurement
• Significant digits are those digits
that are certain in your measurement
plus one estimated
Rules of Significant Digits
• Digits 1-9 are always significant.
• A zero between 2 non zero’s is
significant (203 meters)
• If a decimal is present, zeros left of the
first non zeros are placeholders and
not significant. (0.000244 grams)
• If a decimal is present, zeros right of
non zeros are significant (345.00 L).
Atlantic Pacific Rule
• If decimal is Absent
starting from the
right count all digits
after the 1st non
zero
• If decimal is Present
starting from the left
count all digits after
the 1st non zero
Practice
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4500 Liters
0.00543 grams
0.00607000 seconds
500,003 meters
400,000. Joules
5000340035.000 Amps
Exact Numbers
• Remember that the rules of Sig Figs
only apply to measurements and not
exact numbers.
• Years in a century
• Ounces in cup
• Centimeters in a meter
Rounding Significant Figures
• Review determining the number of sig figs.
• Be able to round any number to the
correct number of sig. figs.
Rounding Sig Figs
• When rounding remember to keep the
value of the number the same.
• Remember to round up if last digit is 5
• Round 12.5 to 2 sig figs
• Round 56.99392882 kg to 3 sig figs
• Round .00027262299 mL to 4 sig figs
• Round 303 meters to 3 sig figs
• Round 303 meters to 2 sig figs
0.057010 g
19.0550 kg
1,809,000 L
Significant Figures
• Review determining Sig. Figs.
• Review rounding with sig. Figs.
• Be able to solve multiplication division
problems showing the answer in the
correct number of sig.figs.
• Be able to solve addition subtraction
problems showing the answer in the
correct number of sig. figs.
Multiplying / Dividing SigFigs
• When multiplying/dividing
measurements you are limited by the
measurement with the least significant
digits.
• Your answer has the same number of
significant figures as the measurement
with the least significant digits
Area
6.15 m x 4.026 m
Volume
3.05 m x 2.10 m x 0.75
m
Adding / Subtracting SigFigs
• When adding/subtracting
measurements you need to keep the
last place holder in common with all
the measurements
165.86g + 4.0911g +
27.32g +141g
150mL + 76.9mL +
209mL + 10.03mL