Calculating with Significant Figures Answer Key (CHEM 1405)
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Calculating with Significant Figures and Scientific Notation
Determine the number of significant figures in each of the following:
__4__a. 6.751 m __4__f. 30.07 mL __4__k. 54.52 g
__3__b. 0.0157 kg __1__g. g __4__l. 0.1209 mL
__4__c. 28.00 L __2__h. 0.0067 mg __5__m. 2.6900 kg
__2__d. 2500 m __3__i. 0.0200 cm __4__n. 43.07 m
__4__e. 0.07002 dm __3__j. m __3__o. 106. km
Express each answer using the correct number of significant figures.
Add
a. 16.5 cm + 8 cm + 4.37 cm = _________29 cm______
b. 13.25 g + 10.00 g + 9.6 g = ________32.9 g_______
c. 4.5 cm + 375 mm + 25.9 dm = ________301 cm______
Subtract
a. 23.27 km - 12.058 km = ________11.21 km____
b. 13.57 g - 6.3 g = ________7.27 g_______
c. 5.805 L - 385.2 mL = ________5.420 L______
Multiply
a. 2.6 cm x 3.78 cm = ________9.8 cm2______
b. 6.50 m x 0.37 m = ________2.4 m2_______
c. 1.4 m x 8m x 75.85 m = ________800 m3_______
Divide
a. 35 cm2 / 0.62 cm = ________56 cm_______
b. 0.75 g / 0.003 cm3 = ________300 g/cm3___
c. 6.50 m / 9.2 m = ________0.71 (no unit)
Rank these numbers from smallest to largest using number 1 through 8.
__6__a. 5.3 x 104 __2__e. 0.0057
__7__b. 57 x 103 __1__f. 5.1 x 10-3
__3__c. 4.9 x 10-2 __4__g. 0.0072 x 102
__5__d. 6230 __8__h. 2 x 106
For the numbers below, change the regular numbers into scientific notation or write as a regular number if already in scientific notation. Watch out for significant figures.
a. 68902 ____6.8902 x 104___ f. 77900.34 ____7.790034 x 104_
b. 0.754 _____7.54 x 10-1_____ g. 0.000385 ____3.85 x 10-4______
c. 248.0 _____2.480 x 102____ h. 4.5 x 103 _____4500__________
d. 3000 _____3 x 103_________ i. 8.30 x 102 _____830.___________
e. 540.0 _____5.400 x 102____ j. 9.080 x 102 _____908.0__________