3.2. Unit Conversions http://www.ck12.org
Practice Problems- Perform the following conversions.
(a) 0.074 km to m
(b) 24,600μg to g
(c) 1300 ms to s
(d) 3.8× 10 −^5 L toμL
Some metric conversion problems are most easily solved by breaking them down into more than one step. When
both the given unit and the desired unit have prefixes, one can first convert to the simple (unprefixed) unit, followed
by a conversion to the desired unit. An example will illustrate this method.
Sample Problem 3.3: Two-Step Metric Conversion
Convert 4.3 cm toμm.
Step 1: List the known quantities and plan the problem.
Known
- 1 m = 100 cm
- 1 m = 10^6 μm
Unknown
- 4.3 cm = ?μm
You may need to consult the table in the lesson, “The International System of Units," for the multiplication factor
represented by each metric prefix. First convert cm to m; then convert m toμm.
Step 2: Calculate.
4 .3 cm× 1001 mcm×^10(^6) μm
1 m =^43 ,^000 μm
Each conversion factor is written so that unit of the denominator cancels with the unit of the numerator of the
previous factor.
Step 3: Think about your result.
A micrometer is a smaller unit of length than a centimeter, so the answer in micrometers is larger than the number
of centimeters given.
Practice Problems
- Perform the following conversions.
(a) 4.9× 107 μg to kg
(b) 84 dm to mm
(c) 355 nm to cm
(d) 70.5 ML to mL