How Much Energy Is Needed to Heat a Saucepan and Water?

[randomkent]

Homework Statement

A saucepan of thermal capacity 500J/degC contains 5kg water at 20 degrees celsius. How much energy is required to raise the temperature of the saucepan and water:
a) to 60 degrees
b) by 60 degrees

Homework Equations

Q = mcΔt
mcΔt = mcΔt

The Attempt at a Solution

First I just did Q = 5 * 500J * 40 = 100 000J, but then I realized mcΔt = mcΔt possibly had to be used. Please help get me on the right track asap! :)

 

[technician]

You need to know the SHC of water to calculate the heat energy required for the water.
You are given enough information to calculate the heat energy required by the pan.

 

[randomkent]

So would it be 2 separate answers for a, 100 000J for the water and 840 000J for the pan?
Or would it be 500*5*(60-T) = 4200*5*(60-20)
Or does the correct method derive one answer... I'm seriously lost .-.

 

[technician]

You have to calculate the total energy (pan+water) each time
500*5*(60-20) + 4200*5*(60-20) is correct for part(a)
Can you see how to do part (b)... a very subtle difference

 

[randomkent]

Are you sure? I was unsure about that because it doesn't account for transferred energy..

 

[Vipho]

Thermal capacity is not specific heat capacity

 

[technician]

Thermal capacity refers to an object, the pan needs 500J to change its temperature by 1C
Specific heat capacity refers to a substance, water needs 4200J to raise the temp of
1kg by 1C. Specific means 'per kg'
I think I have made a mistake in my previous post... the pan should be 500*(60-20)
I think that is what Vipho has picked up... SORRY... careless.