# Heat Question

1. Nov 1, 2005

### Ryan231

I've got a question to solve.. Just need 1 thing..

An automobile cooling system holds 18L of water. How much heat does it absorb if its temperature rises from 20ºC to 90ºC?

I need to find how many kg of water I have... and then plug into

Q =mc(T1-T2)

Q = (m)(4186)(-70)

Look good? just need help with converting 18L of water into kg\

Sorry this seems like a school question... I'm just not sure about converting from L to kg.. seemed like general physics to me

Last edited: Nov 1, 2005
2. Nov 1, 2005

### ranger

If memory serves me correct, 1 liter of water has a mass of approximately 1 kilogram.

EDIT: to be more precise, 1 liter weighs 0.96 kilograms.

3. Nov 1, 2005

### Ryan231

18L*.96 = 17.28kg of water...

So. Q= (17.28)(4186)(70)
= 5063385.6J

I think thats right?

4. Nov 2, 2005

### davidchandler

Density of Water

As I understand it, the gram was defined as the mass of 1 cm^3 of water (at 4°C). That would make 1 liter of water exactly 1 kg. Where are you getting the .96 figure?

5. Nov 2, 2005

### ranger

Um...I went on wikipedia and did a search on liter
http://en.wikipedia.org/wiki/Liter

They said that
Its that almost exactly thing that made me do s ome searching.
here is where I got 0.96 from.

Last edited: Nov 2, 2005