Conversions in chemistry are completed the same way as was done way back when we did dimensional analysis. We start with the original information over one, to ensure that number is in the numerator. Then, you multiply that number by the conversion factor with the units you want in the numerator and the units of the original information in the denominator. Simple conversions will only have one conversion factor; more difficult conversions will have more than one.
There are many conversions a chemist can complete. Please note that each one has to have the units of moles somewhere. This is a small list of the many you can do:
- mass – to – moles
- moles – to – mass
- molecules – to – moles
- moles – to – molecules
- liters – to – moles
- moles – to – liters
- moles – to – moles (two difference compounds)
Example:
Question – How many grams are there in 4.5 moles of NaCl?
- The conversion factor necessary to convert between moles and grams is the molar mass since both these units are used to describe molar mass.
- Calculate the molar mass of NaCl using previously mentioned procedures: 58.4424 g/mol.
- Put the 4.5 mole NaCl in the numerator and set up the conversion factor so the units cancel.
- Multiple the top, multiple the bottom, divide the two numbers to find that the mass is = 262.9908 g NaCl.
- Keep in mind you still need to remember units and to round to the correct sig figs. The answer becomes 260 g NaCl.