chemistry
posted by Anonymous on .
when 84 joules of heat are added to 2.0 grams of water at 15 degrees C, what will be the final temperature of the water?
A. 50. degrees C
B. 5.0 degrees C
C. 25 degrees C
D. 15 degrees C

Let's see if you can do that in your head, knowing that 4.18 joules is 1 calorie. (a good number to remember)
80 joules is therefore very close to 20 calories.
Since the specific heat of water is 1.0 calories per degreegram, 20 calories is enough to heat 2 grams 10 degrees C.
If you start at 15 C, and add 10, what do you end up with for the temperature? 
jhb