**Problem**

When one gram of gasoline burns in a car's engine, the amount of energy given off is approximately 1.03 x 10

^{4}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 10

^{4}cal x 4.184 J / 1 cal = 4.31 x 10

^{4}J

**Answer**

4.31 x 10

^{4}J (note that 3 significant figures are used to report the answer)