posted by Sam on .
A car travels at 60 miles per hour and gets 15 kilometers per liter of gasoline.
How many gallons of gasoline are needed for a 2.2-hour trip?
I'm confused on how to set-up conversion factors.
Conversion factors are set up so that units you don't want cancel and those you want stay. For example, convert 100 mg to g. You know 1000 mg = 1 g
So 100 mg x (1g/1000mg) = ?? NOte You know to place it as 1g/1000 mg and not 1000 mg/1g. As 1g/1000 mg, the mg unit cancels (the unit you don't want to keep) but the unit g stays (you want the answer in grams). If you did it the other way it would be 100 mg x (1000 mg/g) and the units would tell you the answer can't be right because the units are mg^2/g but you know that isn't right because you wanted grams.
How many milliliters of 0.135M potassium hydroxide are required to completely neutralize 14.0mL of 0.150M H2So4 ?