# Chemistry

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A cup of teat containing 400g of liquid at 20 degrees celsius was heated. If 58.5 kj of heat was absorbed by the tea, what would the final temperature be? Assume that the specific heat of the tea is the same as that of water (4.18).

I am not sure how to start this problem.

Chemistry - DrBob222, Saturday, January 21, 2012 at 6:34pm
You know the specific heat formula of
q = mass x specific heat x (Tfinal-Tinitial). Start there. Substitute and solve for Tf

I did 400/58.5 (4.18) and got 28.6 degrees celsius which is one of the answer choices. Was I suppose to use the 20 degrees that was stated in the problem?

• Chemistry - ,

Of course. I don't understand why you are having so much trouble with this. I gave you the equation and it's just a case of substituting the numbers and solving for Tf = Tfinal.
q = mass x specific heat x (Tf-Ti)
58,500 = 400 x 4.18 x (Tf-20)
Solve for Tf.

• Chemistry - ,

I am having trouble with getting Tf by itself that's all.

• Chemistry - ,

OK. Algebra is your problem. This is like
500 = 4 x (T-20)
500 = 4*T - 4*20
500 = 4T - 80
500+80 = 4T
580/4 = T
T = 145

58,500 = 400 x 4.18 x (Tf-20)
58,500 = (400*4.18*T) - (400*4.18*20)
58,500 = 1672.76Tf - 33440

I will let you you finish?

• Chemistry - ,

Ok I got 54.9 which would round to 55 which is an answer choice that they gave me.

• Chemistry - ,

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• Chemistry - ,

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