Chemistry I-Honors
Intro Math Practice
Answer Key
How many significant digits are in the following measured quantities?
4
1.
2
0.0030 x 10 microns
3.
5
3.0404 x 10-2 Newtons
2.
1
80,000 snails
4.
4
0.003040 slugs
Be sure to put your answer in the correct number of sig figs or points will be deducted.
5.
425
1.257 dekaliters is equivalent to how many fluid ounces?
1.257 dkL ( 10 L / 1 dkL)( 1 qt. / 0.946 L)( 32 fl. oz. / 1 qt.) = 425.20
6. F
How many times bigger is a kilometer compared to a picometer (10 raised to what power)?
3
13
10
12
-12
15
A) 10
B) 10
C) 10
D) 10
E) 10
F) 10
1 pm ( 10-12 m / 1 pm)( ( 10-3 km / 1 m) = 10-15 , so a kilometer is 1015 times bigger
7.
5.6 x 10-3 mph
A snail is burning up the trail at a blistering pace of 2.5 m/millisecond. How fast
is it traveling, in units of miles per hour?
2.5 m
103 msec 3600 sec.
10-6 m.
10-3 km.
1 mi.
--------- x ---------- x ----------- x --------- x ----------- x ------------- = 5.6 x 10-3 mph
1 msec
1 sec
1 hr.
1 m.
1 m.
1.609 km.
8.
10.20 ft
3
If a cube has a total volume of 30.06 m , what is the measure of a side, in feet?
3 30.06m3
= 3.109 m
3.109 m ( 102 cm / 1 m)( 1 in. / 2.54 cm.)( 1 ft. / 12 in. ) = 10.201
9. 5.05 x 1016 nm
How many nanometers are there in 0.0505 Gigameters?
0.0505 Gm ( 109 m / 1 Gm)( 109 nm / 1 m) = 5.05 x 1016 nm
10. 12 g/ml
A student does a density determination lab by measuring the volume of an object
using the volume displacement method. The initial volume reading of the water in
a graduated cylinder is 20.0 ml and the final volume (when the object was placed
into the cylinder) is 28.9 ml. If the mass of the object is 104.67 grams, what is the
experimental density of the object?
104.67 g / (28.9 ml - 20.0 ml) = 11.76 g / ml
Convert the following temperatures:
o
11 -222.0 F =
o
o
-141.1 C
o
(-222.0oF - 32) / 1.8 = -141.1 C
12.
755 F
=
675 K
(755oF + 460.) / 1.8 = 675
13.
125 K
=
225 R
125 x 1.8 = 225 R
14.
–40.0 C =
15.
o
278
o
-40.0 F (point where the two scales intersect!)
What is the specific gravity of sulfur trioxide gas at STP conditions?
80.1 g/mole ( 1 mole / 22.4 liters) = 3.58 g/ L
3.58 g / L / 1.29 g/ L = 2.78
16.
6.23 g/ml
If an object has a mass of 46.77 grams when weighed in air, but when suspended in
water, it only weighs 39.26 grams, what is the density of this substance?
46.77 g / [(46.77 g. - 39.26 g.)( 1.0 ml / 1 g.)] = 6.23 g/ml
17.
0.519 g/cm3
3
What is the density (in g/cm ) of a regular metal cylinder if it has a mass of 322 grams,
a height of 355 mm and a radius of 23.6 mm?
V = r2h = 3.14(2.36 cm)2(35.5cm) = 621 cm3
D = 322 g. / 621 cm3 = 0.519 g / cm3
18.
1.9 x 104 hg.
An object that has a mass of 2.1 tons. What is its equivalent mass, in hectograms?
2.1 tons ( 2000 lbs. / 1 ton)( 453.6 g. / 1 lb.)( 10-2 hg. / 1 g.) = 1.9 x 104 hg.
19.
15.5 gal.
How many gallons of water will fit into a waterproof container that measures 18.8 in.
o
by 40.0 cm by 0.335 yds.? Assume that the temperature of the water is 4 C.
18.8 in. (2.54 cm / 1 in.) = 47.75 cm.;
0.335 yds. ( 36 in. / 1 yd.)(2.54 cm / 1 in.) = 30.63 cm.
V = 47.8 cm x 30.6 cm x 40.0 cm = 5.85 x 104 cm3
5.85 x 104 cm3 ( 1 qt. / 946 ml)( 1 gal. / 4 qts.) = 15.46 gal.
20.
5.328 cm
If a regular metallic sphere of lead has a mass of 15.85 pounds, what would be the
radius of this ball, in units of cm? Use the density for lead from your periodic table.
15.85 lb. (453.6 g. / 1 lb.)( 1 cm3 / 11.35 g.) = 633.4 cm3 = volume
633.4 cm3 = 4/3r3 => r3 = 151.222 cm3 => r = 5.32769 cm