Dimensional Analysis and Significant Figures Review
1. Solve the following problems and express the results with the correct number of significant figures and units.
a. 3.894m x 2.16m = 8.41m2
b. 2.96g + 8.1g + 5.0214g = 16.1g
c. 485g ÷ 9.231mL= 52.5g/mL
d. 2.46cm x 2.0cm = 4.9cm2
e. 9.146s - 9.137s = 0.009s
f. (5.12 x 104L) x (6.8726 x 10-9L) = 3.52 x 10-4L2
2. The mass of the sun is 1.989x1030 kg and the radius is 696000 km. What is the average density of the sun in
kg/km3? In g/cm3? (Assume the sun is spherical so V= 4/3πr3.)
1.41 x 1012 kg/km3
1.41 x 104 g/cm3
3. Conversions: Express the following quantities in the units asked for:
a. Speed of light, 2.998 x 108 m/s, in miles per hour and feet/min.
6.746 x 108 mph
5.880 x 1010 ft/min
b. Speed of sound, 740 mph, in
i.
km/ hr
1200 km/hr
ii.
m/s
330 m/s
c. Length of a C-C bond in diamond, 1.54452 Å, in cm, m, and inches. (1 m = 1010 Å)
1.54452 x 10-10 m ; 1.54452 x 10-8 cm ; 6.08079 x 10-9 in
d. Temperature
i.
Liquid nitrogen, -195 oC, in F and K
-324oF ; 78K
ii.
Body Temp, 98.6 oF, in oC and K
37.0oC ; 310.2K
4. What is the number of atoms present in 2.0 moles of helium gas?
1.2 x 1024 atoms
5. Convert 3.770X1027 atoms of gold to moles of gold.
6.262 x 103 moles
6. How many significant figures are in each of the following?
a. 1.92 mm 3
b. 0.030100 kJ
5
c. 6.022 x10 atoms 4
h. 0.001g
5
3
e. 0.00036 cm
3
g. 1001 seconds
23
d. 460.00 L
f. 100 people
i. 0.01 m
4
1
1
2
7. Record the following in correct scientific notation:
a. 350,000,000 cal
3.5 x 108
b. 0.0000721 mol
c. 0.0000000809 Ǻ
d. 765,400,000,000 atoms

7.21 x 10-5
8.09 x 10-8
7.654 x 1011
Don’t forget to study about matter and the changes it undergoes (including properties and classification), as well as
accuracy, precision and percent error.