2 II.1 Unit ConversionsYou MUST learn and use the unit conversion method (not your own method!)A CONVERSION FACTOR: is a fractional expression relating or connecting two different units.
3 II.1 Unit ConversionsExample 1: There are 60 seconds in 1 minute. In statement form,1 min = 60 secConversion Factors:The conversion factor relates 2 units (minutes to seconds).
4 II.1 Unit Conversions Example 2: $1.44 per dozen eggs. Conversion Factors:Conversion factors do not change the VALUE of something, they just change the UNITS.To change the UNITS, multiply by the CONVERSION FACTOR.
5 II. 1 Unit Conversions THE UNIT CONVERSION METHOD: We need 3 important pieces of information:unknown amount and unitsinitial amount and unitsconversion factor (relating the initial units to units of unknown)
6 II. 1 Unit Conversions Example 3: How many seconds are in 20 minutes? Unknown amount:Initial amount:Conversion factor:Solution** ALWAYS include UNITS in your calculations!
7 II.1 Unit ConversionsExample 4: If a car can go 90km in 1 h, how far can the car go in 6.5 h?Unknown amount:Initial amount:Conversion factor:Solution
8 II.1 Unit ConversionsExample 5: If the price of gas is $1.10 per liter (l), how much will it cost to fill a 40 liter tank?Unknown amount:Initial amount:Conversion factor:Solution
9 II.1 Unit Conversions HOW TO PUT EVERYTHING TOGETHER The general form of a unit conversion calculation is:(Unknown amount) = ( Initial amount) x (Conversion factor)
10 II.1 Unit Conversions Example 6 a. If mL of gold has a mass of 3.86 g, what is the mass of 5.00 mL of gold?Unknown amount:Initial amount:Conversion factor:Solution
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 mL of gold has a mass of 3.86 g, what is the volume occupied by g of gold?Unknown amount:Initial amount:Conversion factor:Solution
12 II.1 Unit Conversions SUMMARY Identify unknown 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 cancel. You want to be left with units of unknown amount!)4. Complete the problem by multiplying and/or dividing amounts of RHS.
14 II.1 Unit Conversions Multiple Unit Conversions We can solve problems that require more than one conversion factor.Example:If eggs are $1.44 per dozen, and if there are 12 eggs in a dozen, how many individual eggs can be bought for $4.32?ANALYZE THE PROBLEM:Unknown amount:Initial amount:Conversion factors:
15 II.1 Unit Conversions Solution: we require the connection conversion factor 1 gives the connection:conversion factor 2 gives the connection:Combining conversion factors 1 and 2 gives:
16 II.1 Unit Conversions Solve for unknown amount: Unknown amount = Initial amount x Conversion factors (1 and 2)