UNIT II.1 Unit Conversions Slide 2 II.1 UNIT CONVERSIONS In
chemistry, we will be converting from one unit to the other all the
time You MUST learn and use the unit conversion method (not your
own method) it will make your life easy! A CONVERSION FACTOR: is a
fractional expression relating or connecting two different units.
Slide 3 II.1 UNIT CONVERSIONS Example 1: There are 60 seconds in 1
minute. This is a statement form. We can also write it as: The
conversion factor relates 2 units (ex; minutes to seconds). Slide 4
II.1 UNIT CONVERSIONS Example 2: $1.44 per dozen eggs. Conversion
Factors: Conversion factors do not change the VALUE of something,
ever. We simply use them to change from one unit to another! Slide
5 II. 1 UNIT CONVERSIONS THE UNIT CONVERSION METHOD We need 3
important pieces of information: Desired amount and units ( what we
want ) Initial amount and units ( what we know/already have )
Conversion factor (relating the initial units to units of unknown)
Slide 6 II. 1 UNIT CONVERSIONS Example 3: How many seconds are in
20 minutes? Slide 7 II.1 UNIT CONVERSIONS Example 4: If a car can
go 90km in 1 h, how far can the car go in 6.5 h? Slide 8 II.1 UNIT
CONVERSIONS Example 5: If the price of gas is $1.10 per liter (l),
how much will it cost to fill a 40 liter tank? Slide 9 II.1 UNIT
CONVERSIONS HOW TO PUT EVERYTHING TOGETHER The general form of a
unit conversion calculation is: (wanted amount) = ( Initial amount)
x (Conversion factor) Slide 10 II.1 UNIT CONVERSIONS Example 6 a.
If 0.200 mL of gold has a mass of 3.86 g, what is the mass of 5.00
mL of gold? Slide 11 II.1 UNIT CONVERSIONS *Important: Always ask
yourself which way do I have to write the conversion factor so that
my units cancel properly? b. If 0.200 mL of gold has a mass of 3.86
g, what is the volume occupied by 100.0 g of gold? Slide 12 II.1
UNIT CONVERSIONS SUMMARY Identify wanted/desired amount and its
units (put on left side of = sign). Identify the initial amount and
its units (put on right side of = sign). 3. Identify conversion
factor. (Multiply initial amount by conversion factor in such a way
that one of the units cancels. You want to be left with units of
wanted amount!) 4. Complete the problem by multiplying and/or
dividing Slide 13 p 14. Exercise 2 d) How many seconds must an
electrical current of 35 coulombs/s flow in order to deliver 200
coulombs? Slide 14 Practice Questions: Hebden, p 11 Exercise 1. a,
c, e, g, i p 14. Exercise 2. b, f, h, j Slide 15 Multiple
CONVERSIONS The automobile gas tank of a Canadian tourist holds
39.5 l of gas. If 1 L of gas is equal to 0.264 gal in the USA (gal
is the symbol for gallon, a measure of volume used in the US), and
gas is $1.26/gal in Dallas, Texas, how much will it cost the
tourist to fill his gas tank in Dallas? Slide 16 Exercise 4, page
15 Slide 17 Practice time Hebden, p 15 Exercises 3 10 except 4
