Chemistry Reference
In-Depth Information
EXAMPLE 2.27
How many kilometers are in 206 m?
Solution
There are 1000 m in 1 km, by definition.
1 km
1000 m
Definition
of kilo-
Meters
Kilometers
206 m
a
b
0.206 km
Practice Problem 2.27
How many millimeters are in 1.04 cm?
Mass
As stated earlier, the primary unit of mass in the metric system is the gram.
Because the gram is so small, however, the standard mass in SI and the legal
standard in the United States is the kilogram.
EXAMPLE 2.28
How many grams are in 1 kg?
Solution
The prefix
kilo-
means 1000 of whatever it is attached to. Therefore, 1 kg is
1000 g.
Practice Problem 2.28
How many grams are in 1 mg?
EXAMPLE 2.29
Airlines usually have a 15-kg free-baggage allowance for overseas travelers.
(a) How many grams does this allowance represent? (b) How many pounds?
Solution
(a)
a
1000 g
1 kg
15 kg
b
15,000 g
Definition
of kilo-
Kilograms
Grams
(b) From Table 2.4, we see that 1 kg = 2.20 lb:
a
2.20 lb
1 kg
15 kg
b
33 lb
2.20 pounds
kilogram
Kilograms
Pounds
Practice Problem 2.29
Calculate the mass of a 207-lb person in
kilograms.
