- #1

462chevelle

Gold Member

- 305

- 9

## Homework Statement

if you burn 1 gallon of gas and it makes 48kJ. can you calculate the amount of mass lost.

## Homework Equations

law of conservation: Energy cannot be created or destroyed it just changes form.

## The Attempt at a Solution

the way i look at this problem is that there is no loss of mass. the mass is just converted from a liquid to a gas since you cannot destroy energy. but i feel like i shouldnt be looking at it this way and i should be thinking of a way to model it in an equation. the question header is rest energy. and the only equation the book has under rest energy is e=mc^2. and i dont feel like that would apply here since i know all the variables. i dont need to solve for anything. any ideas?

thanks,

Lonnie