## Unit Conversions

In Chemistry, there is often a need to convert from one unit to another when making calculations with date obtained during experimentation or observation. There are a variety of different units and types of measurement used even in basic chemistry. There also exist many ways of transferring from one type of unit to another based upon the needs of the calculation.

## Numbers in Chemistry

As chemistry often involves very precise measurements for the masses, volumes, etc. of compounds and other things, a special system of interpreting numbers is used. It is based upon

Now, say you measured an object to be 2000 mm, but the smallest unit on your measuring tape is a centimeter. Because of this, you can not really get an accurate measurement of the final 0 in 2000 mm, so it only has 3 significant digits as this is the maximum accuracy to which you can measure the object. The final zero is there as a placeholder, to indicate that 2000 is really 2000 and not 200.

**significant digits**. To identify the amount of significant digits, use the following rules:- Any non-zero number is significant.
- Any zero between two non-zero numbers is significant.
- Zeros at the end of a number and to the right of a decimal point are significant.
- Here's the tricky one: Zeros at the end of a number but to the left of a decimal may or may not be significant. If they have not been calculated but acts as a placeholder, it is not significant. A decimal after zeros at the end of a number makes them significant.

Now, say you measured an object to be 2000 mm, but the smallest unit on your measuring tape is a centimeter. Because of this, you can not really get an accurate measurement of the final 0 in 2000 mm, so it only has 3 significant digits as this is the maximum accuracy to which you can measure the object. The final zero is there as a placeholder, to indicate that 2000 is really 2000 and not 200.