Question
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.
How many gallons of gasoline are needed for a 2.2-hour trip?
I'm confused on how to set-up conversion factors.
Answers
DrBob222
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.
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.
zebra
How many milliliters of 0.135M potassium hydroxide are required to completely neutralize 14.0mL of 0.150M H2So4 ?