# Homework Help: Heat phenomena

1. Apr 25, 2012

### kimkibun

1. The problem statement, all variables and given/known data

An aluminum vessel hose mass is 178g contains 90g of water at 15.5°C. How many calories of heat are required to bring the water to a final temperature of 85°C? The specific heat of water is 1cal/g°C.

Given:
mAl=178g
mH2O=90g
T1=15.5°C
T2=85°C
cH2O=1cal/g°C

2. Relevant equations
Im planning to use this formula for heat quantity

QH2O=mH2OcH2OΔTH2O

where ΔTH2O=T2-T1

3. The attempt at a solution
Since what we need is QH2O i just ignore mAl, using the above formula i got

QH2O=(90g)(1cal/g°C)(85-15.5)°C=6300cal

is this correct?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Apr 26, 2012

### Staff: Mentor

You're halfway there What about the enclosing aluminum vessel? Doesn't its temperature have to be raised to the final value also?

3. Apr 26, 2012

### kimkibun

do i need to get QAl?

4. Apr 26, 2012

### Staff: Mentor

I don't see how you can heat the water without also heating the vessel that contains it. So I'd have to say yes, you should add the heat required to raise the temperature of the aluminum vessel too.