## heat problem

**Anonymous**

How much heat (in kj) is given out when 85.0g of lead cools from 200 degrees celsius to 10 degrees celsius? (Cp of lead is 0.129 J/g-celsius

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Anonymous| 20 January 2005 - 9:24am## Re: heat problem

[quote="lilromo89"]How much heat (in kj) is given out when 85.0g of lead cools from 200 degrees celsius to 10 degrees celsius? (Cp of lead is 0.129 J/g-celsius[/quote]

What equation do you think you should use here?

Looking at the units of the heat capacity (C[sub]p[/sub]) that you have, it looks like the equation should be:

C[sub]p[/sub] =[u][color=#dddddd]E[/color] ∆H [color=#dddddd]C[/color][/u]

[color=#dddddd][sub]p[/sub] =AE[/color][sup]m×∆T[/sup]

Where ∆H is the Change in heat (in J)

m = mass of object (in g)

∆T = Change in Temperature (in °C or K)

Rearrange & calculate!

(Remembering at the end that 1000J == 1kJ)

Anonymous| 22 January 2005 - 4:08am## is this the answer to the heat problem

2083.35kj

Anonymous| 23 January 2005 - 2:56pm## Re: heat problem

[quote="allan_chemist"]Where ∆H is the Change in heat ([color=Red][b]in J[/b][/color])

m = mass of object (in g)

∆T = Change in Temperature (in °C or K)

Rearrange & calculate!

([color=Red][b]Remembering at the end that 1000J == 1kJ[/b][/color])[/quote]

[quote="lilromo89"]2083.35kj[/quote]

Yes, that's correct, but your units are in correct.

Note the bits I have highlighted in red, then adjust your units!