Re: Homework help thread!

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I need to get this done for Monday, here are the questions;

How much energy is needed for each of the following?
a.To raise the temperature of 2.0kg of aluminium by 30 degrees Celsius
b.To raise the temperature of 0.05kg of water from 20 degrees Celsius to 60 degrees Celsius
c.To heat a 20kg concrete block in a storage heater from 10 degrees Celsius to 40 degrees Celsius
d.To heat 1.5kg of water from 20 degrees Celsius to boiling point

Help would be very much appriciated

Ahh, this is about the specific heat capacity of elements. There's a nifty little equation you can use to do this, and these are pretty bog standard questions related to this. I did my whole chemistry coursework on this topic, so I'm used to things like this. The equation is E=MC∆T.
E means the energy needed/given off; M is the mass of the object; C is the specific heat capacity of the substance (look this up for each one, and check you're in the right unit (g or kg)!), which means the energy required to raise one gram/kilogram (depending on the question) of the substance by one degree Celsius; ∆T is the change in temperature, or rather the amount of °C the substance has been raised by.

If this doesn't make sense, then the good old BBC can help out: http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/heatingandcooling/buildingsrev3.shtml

Hope this helps

I already knew this but it was laying dormant until I looked in my book  buuut...the problem now is I don't know the specific heat capacity of 2.0kg of aluminium, 0.05kg of water,20kg of concrete or 1.5kg of water :/ and I need those numbers to do the equation...