Know 5 basic units Be able to combine base units Be able to convert base units to different sizes using prefixes Be able to do math with units. Be able to use a few non-standard (but traditional) units used frequently in chemistry.

Quantity being measured Length Mass Time Temperature Amount of Substance (counting atoms!) Corresponding Unit meter (39.36 inches) kilogram (not gram!, 2.2 lbs ) second Kelvin (not o C) mole

Combined Unit m/s L x W or m 2 L x W x H or m 3 kg/m 3 mole/m 3 speed area volume density concentration Quantity being measured

Volume – these 4 are equivalent 1 dm cm 3 1 Liter (L)1000 milliliters (mLs) dm 3 is equal to how many mLs?

o C = K K = o C o F = ( o C + 40) x 9/ o C = ( o F + 40) x 5/9 - 40

Same units add or subtract w/o unit change: 3 m + 5 m = 8 m Same quantity units with different prefixes must be converted before adding or subtracting: 300 K + 3 kK = 3300 K Different quantity units can’t be added or subtracted: 3 sec - 4 moles = ???

When same units multiply or divide the result is a combined unit: 3 m x 5 m = 15 m 2 Same quantity units with different prefixes must be converted before multiplying or dividing: 300 cm x 4 m = 12 m 2 or 120,000 cm 2 Different quantity units can be multiplied or divided: 3 moles ÷ 4 L = 0.75 mol/L