in this video we're going to look at units of measurement in chemistry more specifically we're going to learn about SI units derived units and metric prefixes it's important to know that all measurements will have a number and a unit you would never say I have three three of what this always needs to be clarified for example if you had 70 kilg of something you would need to say I have 70 kilg not I have 70 the SI system from the International System of Units uses based units as the basis for all other units the units are listed in the table and include kilogram for the mass meters for length seconds for time Kelvin for temperature ampere for electrical current moles for the amount of something and Candela for luminous intensity you might notice that the base unit for mass is the only one with the metric prefix when you combine one or more base units you get the derived units are units that are made from more than one base unit you may be familiar with many of these such as density which is the mass divided by the volume or velocity which is the length divided by the time also volume is a derived unit which comes from length cubed one important relationship is that 1 cm cubed is equivalent to 1 Mill the jewel which is a unit of energy is equivalent to kilog time me S over second s there are a wide variety of metric prefixes that be can be added in front of either the base unit or the derived unit as as you can see from the table here do you really need to know all these most likely No in fact if you're just beginning your Chemistry journey I recommend learning only the following kilo CTI Millie micro and Nano by placing the prefix in front of the base unit that means you have a certain number of that base unit for example kilo means a TH or 10 the 3 power therefore a kilo unit such as a kilogram means you have 1,000 G instead of writing out kilogram millisecond or nanogram or any other number of the possible combinations uh there are abbreviations uh these can be abbreviated using the symbol for the prefix and the base unit like we see here and here are few other examples some other uh relationships that you'll knowe are 1 kilogram is 1,000 M 10 second 10 CCs is 01 second and 3 345 microgr is 0.345 G and of course there are a wide variety of other combinations and eventually we'll learn how to convert from one unit to another in this lesson you learned about SI units derived units and metric prefixes if you have any questions leave a comment below and or feel free to message me and thanks for watching