## Quiz of the Week - Chemistry 221 The Metric System

Master the concepts from this week's material by trying these quiz questions which will NOT affect your grade in any way. All scoring is anonymous and known only to you, the user! If you have any questions, please contact me. Good luck!

__A Quick Review of the Metric System__

The metric system is based upon powers of ten, and its versatility to a variety of measurements (i.e. mass, length, volume, etc.) makes it indispensable for scientists. Here are the five primary metric prefixes you will need to master in chemistry:

*kilo:* k = 10^{+3}
*centi:* c = 10^{-2}
*milli:* m = 10^{-3}
*micro:* µ (the Greek "mu" symbol) = 10^{-6}
*nano:* n = 10^{-9}

As an example, let us use these prefixes with regards to length. The base unit of length is the meter (m), and we can apply our fix prefixes this way:

*kilometer:* 1 km = 10^{+3} m
*centimeter:* 1 cm = 10^{-2} m
*millimeter:* 1 mm = 10^{-3} m
*micrometer:* 1 µm (the Greek "mu" symbol) = 10^{-6} m
*nanometer:* 1 nm = 10^{-9} m

These are just conversions for dimensional analysis like any other. For example,

**How many centimeters in 3.06 km?**

To solve, we will use

- 1 km = 10
^{+3} m
- 1 cm = 10
^{-2} m

We will start with the 3.06 km, then convert this to meters, and finally convert meters into centimeters. Therefore,

- 3.06 km * (10
^{+3} m / 1 km) * 1 cm / 10^{-2} m) = **3.06 x 10**^{+5} cm

Initially we canceled km and were left with meters, then we canceled m and were left with cm.... and this is what the problem asked for, so all is well!

__Chemistry 221 - The Metric System__

1. How many nm in 3.06 m?

2. Convert 3.06 mL into L.

3. How many kg are in 3.31 mg?

4. How many ng are in 3.04 micrograms?

5. Convert 3.14 x 10^{12} ns ("nanoseconds") into days.