Unit Conversion Example Problem - Metric to Metric Conversion

This worked chemistry example problem demonstrates how to convert from metric units to different metric units.

Problem

When one gram of gasoline burns in a car's engine, the amount of energy given off is approximately 1.03 x 10⁴ cal. Express this quantity in joules.

Solution

1 cal = 4.184 J

To convert calories to joules, use the conversion factor 4.184 J / 1 cal.

1.03 x 10⁴ cal x 4.184 J / 1 cal = 4.31 x 10⁴ J

Answer

4.31 x 10⁴ J (note that 3 significant figures are used to report the answer)