SI System of Measurement ….Common chemistry units Base Units: Symbol meter (length) m kilogram (mass) kg second (time) s kelvin (temperature) K mole (amount of substance) mol

Some additional units Volume: cubic centimeter, cm3, cc liter, L milliliter, mL Density: g/cm3, g/mL, g/L Energy: calorie, cal joule, J Pressure: kiloPascal, kPa mm of Hg atmosphere, atm.

kilo… is a large unit (k) Means 1000x (103) 1 kilometer = 1000 meters 1 kilojoule = 1000 joules 1 kg = 1000g etc… 2 Conversion factors: 1km 1000m 1000m 1km

deci… is a smaller unit (d) Means 1/10 or 0.1 (10-1) 1 decimeter is .1meter There are 10 decimeters in 1 meter 2 Conversion factors 10 dm 1m 1m 10 dm

centi… is a smaller unit (c) Means 1/100 or 0.01 (10-2) 1 centimeter is .01meter (1/100 meter) There are 100 cm in 1 m 2 Conversion factors: 100 cm 1m 1 m 100 cm

milli… is a smaller unit (m) Means 1/1000 or 0.001 (10-3) 1 millimeter is .001meter There are 1000 mm in 1 m 2 Conversion factors: 1000 mm 1 m 1m 1000 mm

micro… is very small (μ) Means 1/1,000,000 or 0.000001 (10-6) 1 micrometer (micron) is .000001 meter There are 1,000,000 μ in 1 m 2 Conversion factors: 1x106 μ 1m 1m 1x106 μ

nano… very small (n) Means 1/1,000,000,000 or 0.000000001 (10-9) 1 nanometer is .000000001 meter There are 1,000,000,000 nm in 1 m 2 Conversion factors: 1x109 nm 1m 1m 1x109 nm

Converting between units: (dimensional analysis) Know the definition of units write the definitions as conversion factors Use the one that algebraically cancels the “given” unit Solve the problem Convert 3.5 mm to m: 1 m = 1x10 3 mm 1m 1 x 10 3mm 1 x 10 3mm 1 m 3.5mm x 1m 1x10 3 mm = 3.5x10 -3 m

Converting between units: try it yourself: Convert 2.3x10 3 g to g: (answer is: 2.3 x 10-6 g) know the definition of units write the definitions as conversion factors use the one that algebraically cancels the “given” unit Solve the problem