Chemistry: SI Units & Conversions. SI Base Units of Measure commonly used in chemistry. Time: second (s) Length,distance: meter (m) Mass: kilogram (kg) In class, we consider the “base unit” to be grams. Volume: liter (l) Temperature: Kelvins (K) note: no degree symbol
Kelvins = C + 273
°C = Kelvins - 273
Problem: Convert 32.05 cm to m
Step 1: write down the starting measurement: number and unit!
Step 2: Convert from this prefix to the base unit. (This means meters, liters or grams.)
Step 5 If you have arrived at the target unit, you are done!
Be sure to include the unit and significant figures in your answer!
Step 3: Cancel the units that divide each other out.
Step 4: Perform the math… divide by the numbers on the bottom, multiply by the numbers on the top!
Convert 0.00450 km to cm
The correct answer is 450 cm, but that’s only 2 sig figs…. ?????
Use scientific notation to correct the sig figs!
4.50 x 102 cm