The International System of Measurement (SI)

SI System of measurement used world wide Makes communication between countries, languages and different measurement systems easy, consistent Uniformed – everyone is “speaking the same language”

Base Quantities Base UnitsSymbol LengthMeterm MassGramg VolumeLiterl TemperatureCelsiusC

Prefixes Used to change the size of the value Used in front of the base unit Used to make large numbers smaller and smaller numbers larger Does not change the value itself

Common Prefixes PrefixSymbolValue Power of 10 kilo-k hecto-h deca-da Base unitg,l,m110 0 deci-d-1/ centi-c-1/ milli-m-1/

Unit Conversions Used to change from one sized unit to another Value does not change only the size of the unit ex: 1 dollar = 100 pennies = 20 nickels = 10 dimes = 4 quarters Value ($1) remains the same, just the size of the unit changes

Tools of Measurement Equipment used to measure mass, length, volume and temperature Each tools measures in its own unit The smaller the unit the more accurate the measurement

Tools of measurement (con’t ) Base Quantities ToolsUnits MassBalanceGrams Volume Graduated Cylinder milliliters LengthMetric rulercm/m TemperaturethermometerºC

C. Derived Units Combination of base units. Volume - length  length  length 1 cm 3 = 1 mL 1 dm 3 = 1 L Density - mass per unit volume (g/cm 3 ) D = MVMV D M V

D. Density An object has a volume of 825 cm 3 and a density of 13.6 g/cm 3. Find its mass. GIVEN: V = 825 cm 3 D = 13.6 g/cm 3 M = ? WORK : M = DV M = (13.6 g/cm 3 )(825cm 3 ) M = 11,220 g D M V

D. Density 1) A liquid has a density of 0.87 g/mL. What volume is occupied by 25 g of the liquid? GIVEN: D = 0.87 g/mL V = ? M = 25 g D M V WORK : V = M D V = 25 g 0.87 g/mL V = 28.7 mL

D. Density 2) You have a sample with a mass of 620 g & a volume of 753 cm 3. Find density. GIVEN: M = 620 g V = 753 cm 3 D = ? D M V WORK : D = M V D = 620 g 753 cm 3 D = 0.82 g/cm 3