UNIT 2.2SI UNITS/METRIC CONVERSIONS

SI UNITS

SI = International system of metric units.

Base unit = all other units are multiples of base units or combinations)

Quantity Written unit Symbol

length

mass

time

amount of substance

SI UNITS

2. MULTIPLES OF BASE UNITS (p.17)

Prefix Symbol Exponential

mega M 106

kilo k 103

deci d 10-1

centi c 10-2

milli m 10-3

micro μ 10-6

106

103

10-1

10-2

10-3

10-6

2.2 SI UNITS

3. IMPORTANT EQUIVALENCES

1 mL = 1 cm3

1 m3 = 103 L

1 t = 103 kg

2.2 SI UNITS

Example: Re-write the expression “6 kilograms”

The prefix symbol for kilo is ___ The unit symbol for grams is ___ 6 kilograms =

The exponential equivalent to kilo is ____ 6 kilograms =

METRIC CONVERSIONS

Metric conversions involve using unit conversions between prefix symbols and exponential equivalents.

Example: Write a conversion statement between cm

and m.

METRIC CONVERSIONS

Write conversion statements between each of the following

dm and m

cL and L

dmol and mol

METRIC CONVERSIONS

How many milligrams are in 5 kg?5 kg = ? mgNo direct link between kilo and milli What to do?

Convert to a base unit first !

METRIC CONVERSIONS

Express 7µm in Megametres 7µm =? Mm

METRIC CONVERSIONS

How many decilitres in 0.5kL?

TRY

0.052 GHz = ? kHz Hz is Hertz( a frequency unit)

MULTI CONVERSION

Convert 1cg/ mL into dg/L

MULTI CONVERSION

TRY: Convert 3 mg/L into µg/mL

T

METRIC CONVERSIONS

DERIVED QUANTITIES 

Derived quantity =

Derived unit =

DENSITY

Density is an example of a derived unit What is density?

Density =

DERIVED UNITS: DENSITY

Given that a 2.44 cm3 sample of an element has a mass of 47.14 g. Determine the density of the element.

DERIVED UNITS

Find the volume of a block of wood that has a mass of 34.5 grams. The density of this wood is 12g/cm3

DENSITY

The density of carbon dioxide at standard temperature and pressure is 1.96 g/L. Calculate the mass of a 600 mL sample of carbon dioxide.

The density of air is about 1.29 g/L at standard temperature and pressure. Would carbon dioxide tend to rise up or sink down in the atmosphere? _______________

Homework

Hebden Page19 #13, 14, 15(a,c,d,f,g,i), Page 21 #16 (a,c,e) #17 (b,d,f,h,j,L,n) #18(a, b, c) Page 26 # 31,33, 37