Chemistry 180
Name: ________________________________________
1. Determine the number of significant figures in the following:
10.350
__________
0.004070
__________
2. Perform the following calculations; write the unrounded answer placing a vertical dashed line (⋮) after the last
significant figure, and the answer rounded to the correct number of significant figures:
78.100 cm + 4.9 cm
16.80 g
4.2 mL
Unrounded = _______________________
Rounded = _______________________
Unrounded = _______________________
Rounded = _______________________
3. Write the following in scientific notation:
0.008230
_________________________
456000
_________________________
4. Perform the following calculations and write the unrounded and rounded answers in scientific notation using the
correct number of significant figures:
(8.3 × 102) (5.7 × 10−4)
Unrounded = ______________________________
Rounded = ________________
(6.7 × 105) − (9.2 × 104)
Unrounded = ______________________________
Rounded = ________________
5. List the following measurements from largest to smallest:
largest _____________
_____________
0.50 m
_____________
5000 mm
0.05 cm
_____________
500 km
_____________ smallest
6. Use dimensional analysis (show setup) to make the following conversions and use correct significant figures.
Use only these equivalences to derive conversion factors:
1 km = 103 m
1 kg = 103 g
1 mL = 10−3 L
−3
−2
1 mm = 10 m
1 cg = 10 g
Convert 5.0 × 104 mm to km
Convert 0.0074 kg to cg
Convert 831 mL to L
10 cm
7. Use dimensional analysis, the equation for density, and correct significant figures to solve the following density
𝑚
problems. All solutions must start by rearranging the basic density formula 𝑑 = to solve for the appropriate
𝑉
variable. Then substitute the given values and calculate the answer. Do not substitute values until you have
symbolically solved the equation.
Cough syrup has a density of 0.950 g/cm3. What volume of cough syrup has a mass of 50.0 g?
A copper penny has a mass of 3.1 g and a volume of 0.35 cm3. What is the density of copper?
What is the mass of an object that occupies volume of 4.5 cm3 and has a density of 19.3 g/cm3?
A student determines the mass of a metal rod to be 39.35 g. It is placed In 10.00 mL of water, and the water level
rises to 15.00 mL. What is the density of the rod? Use a table of densities to tell what metal the rod is made of.
(Densities may be found at https://sites.google.com/site/chempendix/densities-of-pure-metals )
8. Convert 2 weeks to seconds; show your setup.
Use only these equivalences to derive conversion factors:
1 week = 7 days
1 day = 24 hours
1 hour = 60 minutes
1 minutes = 60 seconds
9. What are the correct units for the answer to a problem if the following series of conversion factors are used?
km in mi ft m cm
× × × ×
×
=
m ft hr mi cm in
10. Evaluate the following:
(3.5 × 1018 )(1.47 × 106 )(3.442 × 10−3 )(9.97 × 105 )
=
(9 × 1031 )(6.634 × 108 )(2.7 × 104 )(6.02 × 1023 )
11. Given the following exact equivalences, make the following conversion; show your setup:
1 fizzle = ? frizzles
Do not abbreviate units! Do not simplify your conversion factors! Note that single and multiple units cancel,
such as fizzle cancels fizzles (just as inch cancels inches).
4 swizzles=5 twizzles
1 fizzle=3 drizzles
3 twizzles=18 sizzles
1 swizzle=20 frizzles
10 drizzles=4 sizzles
12. Jules Verne wrote a book call Twenty Thousand Leagues Under the Sea. Convert 20,000 leagues to fathoms. Show
your setup. Use only these equivalences to derive conversion factors:
12 in=1 ft
3 ft=1 yd
1 fathom=2 yds
1 stat mile=5280 ft
1 naut mile=6080 ft
1 league=3 naut miles
13. Perform the following conversions. Show your dimensional analysis.:
75 cm to inches
2300 g to pounds
6.0 ft 10 inches to cm
8100 mL to quarts
3.945 × 108 seconds to years (use 1 year = 365 days)
35 mi/hr to m/s
14. Rewrite the following numbers so that they are in proper scientific notation:
652.9 × 105
_________________________
0.0259 × 108
_________________________
759.2 × 10−6
_________________________
0.00598 × 10−15
_________________________
9568.19 × 103
_________________________
15. Chemists have determined that 18.0 ml of water contains 6.022 × 1023 molecules of H2O. Assuming that a teaspoon
holds 3.70 ml of water, how many water molecules are in the teaspoon?
16. At 91¢ per liter, how many dollars will it cost to fill a 15 gallon tank with gasoline?
17. 35 ml of ethyl alcohol (density= 0.789 g/ml) is added to a graduated cylinder that weighs 44.28 g. What will be the
mass of the cylinder plus the alcohol?
18. Given the following exact equivalents, make this conversion:
4 clips = 5 blips
1 knop = 6 bippy
3 blip = 18 pringle
1 knop = ? knips
1 clip = 10 knip
10 bippy = 8 pringle