# How to do unit conversions in chemistry

## 2.6: Problem Solving and Unit Conversions

The second way you can approach this problem is to treat the conversion from milli- to kilo- as one big step:. This is how you construct a conversion factor to convert from one unit to another. Exact numbers are defined or counted numbers, not measured numbers, and can be considered as having an infinite number of significant figures.

These are used primarily in the metric system as a sort of shorthand notation to make numbers easier to express. Grams, moles, and kilograms are all units that describe the amount of matter, while Kelvin describes temperature.

Skills to Develop To convert a value reported in one unit to a corresponding value in a different unit using conversion factors. If there are 16 students in a classroom, the number 16 is exact.

## Chemistry Unit Conversions

This is valuable because certain measurements are more accurate or easier to find than others. Fat is less dense than muscle and other tissues, so as it accumulates, the overall density of the body decreases.

Always check your conversion factor to make sure the correct term cancels out! A generalized description of this process is as follows: Counted numbers are also exact. Perhaps you can determine the answer in your head. Unit conversions are important in all sciences , although they may seem more critical in chemistry because many calculations use different units.

## How to Make Unit Conversions

Then we multiply this quantity by a conversion factor, which is the same as multiplying it by 1. Density can be used as a conversion factor between mass and volume. Here are some common ones:. They can also advise patients on the proper use of their medications, including when and how to take specific drugs properly. Why did we not use that conversion factor? While it may take practice to master unit conversions, you only need to know how to multiply, divide, add, and subtract to do them.

In another form of diabetes, called diabetes mellitus, there is excess glucose dissolved in the urine, so that the density of urine is abnormally high. The gram unit will cancel algebraically, and milliliters will be introduced in the numerator. We know that 100 cm is 1 m, so we have the same quantity on the top and the bottom of our fraction, although it is expressed in different units.

We would use the conversion factor that has milliliters on the bottom so that the milliliter unit cancels and grams on top so that our final answer has a unit of mass:. Pharmacist A pharmacist dispenses drugs that have been prescribed by a doctor. The density of urine can be affected by a variety of medical conditions. From this relationship, we can construct two conversion factors: