HELP!!! Please How do you calcuate heat energy????

Question

The question is "calculate the heat energy required to raise 200g of water @20 degrees celcius to 100 degrees celcius stream."

Answer 1

Use the specific heat formula which is:

q = (m)(dT)(Cp)

where q = amount of heat transferred

m = mass of solution

dT (delta T) = change in temperature

Cp = specific heat

Plug in the values into the equation:

q = (200)(1)(80)

To make things easier, I am using water's specific heat in calories which is just 1 (cal / g)(degree C). If you want the answer in joules, remember that 1 calorie is equal to about 4.18 joules. To get 80, the change in temperature, simply subtract 20 from 100 (100 - 20).

You will get 16000 calories as you answer. If you want it in kcal just divide by 1000 to get 16 kcal. If you want it in joules, multiply 16000 by 4.18 to get 66880 joules. To keep the proper number of significant digits (you need 3 in this case) write the answer in scientific notation.

6.68 x 10^4 J

Answer 2

Use the formula: Q=mCpdT where

Q= heat input (heat energy)

m= mass of the sample in grams

Cp= heat capacity for water= 1 cal/gm-degC

dT= change in temp in degC

Q= 200 gm * 1 cal/gm-C * (100-20) C

Q= 16000 cal, or 16 kcal