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Topic: Chemistry QUestion I am stuck on!!!!  (Read 3381 times)

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Offline Gweedo8

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Chemistry QUestion I am stuck on!!!!
« on: June 26, 2009, 11:56:05 AM »
Aluminum and iron blocks of the same weight are heated to 250◦C. These blocks are dropped into a bucket of water. Assuming enough heat is available in the blocks, which block will heat the water the quickest to 75◦C? Explain

Offline sjb

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Re: Chemistry QUestion I am stuck on!!!!
« Reply #1 on: June 26, 2009, 01:05:26 PM »
How much energy does it take to heat, say 1 kg, iron from 20°C to 250°C ? Similarly, how about 1 kg of aluminium?

Offline Phlogiston

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Re: Chemistry QUestion I am stuck on!!!!
« Reply #2 on: June 26, 2009, 01:32:40 PM »
Aluminum and iron blocks of the same weight are heated to 250◦C. These blocks are dropped into a bucket of water. Assuming enough heat is available in the blocks, which block will heat the water the quickest to 75◦C? Explain

Since it's a conceptual question, you just have to think qualitatively.  What (at least thermochemically) is the only difference between the same mass of Al and Fe?  Then, what effect will that difference have?

Offline Borek

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Re: Chemistry QUestion I am stuck on!!!!
« Reply #3 on: June 26, 2009, 02:17:16 PM »
It doesn't sound as an obvious question to me. I can think of two factors that have to be taken into account - and I am not quite sure which one will be more important.

Just to confirm with the OP: question asks which block will heat the water the quickest? That is, it is all about speed of heat transfer?
« Last Edit: June 26, 2009, 02:51:12 PM by Borek »
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Offline sjb

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Re: Chemistry QUestion I am stuck on!!!!
« Reply #4 on: June 26, 2009, 03:16:16 PM »
Actually, the more I think about it, the more I agree. Sorry for the slight lead in a possibly wrong direction. :-[

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