UNIT II.2 & II.3 PPT SI UNITS & METRIC CONVERSIONS

II.2 SI UNITS 2. MULTIPLES OF BASE UNITS (p.17) ** Need to know this table!!! Written PrefixSymbolExponential megaM10 6 kilok10 3 decid10 -1 centic10 -2 millim10 -3 microμ10 -6

II.2 SI UNITS SI = International system of metric units. Base unit = (all other units are multiples of base units or combinations) QuantityWritten unitSymbol length mass time amount of substance

II.2 SI UNITS 3. IMPORTANT EQUIVALENCES 1 mL = 1 cm 3 1 m 3 = 10 3 L 1 t = 10 3 kg

II.2 SI UNITS Example: Re-write the expression “6 kilograms” using PREFIX and UNIT SYMBOLS an EXPONENTIAL EQUIVALENT The prefix symbol for kilo is ___ and the unit symbol for grams is ___ 6 kilograms = The exponential equivalent to kilo is ____ 6 kilograms =

Q UESTIONS Hebden p. 19 #11-14

II.3 METRIC CONVERSIONS Metric conversions involve using unit conversions between prefix symbols and exponential equivalents. Example: Write a conversion statement between cm and m. ‘c’ stands for _____ then

II.3 METRIC CONVERSIONS Example: How many milligrams are in 5 kg? Unknown amount = Initial amount = Conversion factors = Solution:

II.3 METRIC CONVERSIONS Diagram (p. 20) – how prefix symbols relate to a central base unit: Example 1: Express 7µm in Megametres. m Mmkmdmcmmmμmμm

II.3 METRIC CONVERSIONS Example 2: (p.21 #16e) If 1 dL = L and 1 kL = 10 3 L, how many decilitres in 0.5kL?

II.3 METRIC CONVERSIONS DERIVED QUANTITIES Derived quantity = Derived unit =

II.3 METRIC CONVERSIONS Example: #29a) Find the derived value and units for the molar concentration, c using the equation c = n/V Where n = 0.250mol and V = 0.500L

II.3 METRIC CONVERSIONS Example 3: Convert 1cg/ mL into dg/L Unknown: Initial: Conversion factors = Solution:

ASSIGNMENT Hebden p. 19 #11-14, 15(odds), 16-18, 24, 28, 29