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If 40 J of energy is added to 4 g of water that is at 20C, what will the final t

ID: 494246 • Letter: I

Question

If 40 J of energy is added to 4 g of water that is at 20C, what will the final temperature of the water be? the specific heat of water is 4.184 J g K:. Describe a way to measure the density of a small insoluble object that is denser than water, using only a scale, water, and a graduated cylinder. (This is not in the lab report, but you should be able to figure this out.) What does the variable C. stand for? Write a useful equation that includes C, No numbers are needed. in the course of this lab, you will make several cooling plots. How can one find T using a cooling plot? Why must one use a cooling plot to measure T. ? (See step 7 in the procedure).

Explanation / Answer

1) The amount of energy added , Q = mcdt

Given Q = 40J

m = mass of water = 4 g

c = specific heat capacity of water = 4.184 J/g.K

dt = change in temperature = final - initial = t - 20 oC

Plug the values we get

dt = Q / (mc)

t - 20 = 40 / ( 4x4.184)

t = 22.39 oC

Therefore the final temperature is 22.39oC