Posted by **Debra** on Sunday, October 23, 2011 at 12:56am.

1. How much heat energy is lost by 3 kg of water when it cools from 80 degrees C to 10 degrees C?

2. A 300 g piece of aluminum is heated from 30 degrees C to 150 degrees C. What amount of heat energy is absorbed?

3. Determine the temperature change in each of the following.

(a) 10 kg of water loses 232 kJ of heat energy.

(b) 500 g of copper gains 1.96 kJ of heat energy.

4. After 2 kg of mercury gained 2.52 x 10^4 J of heat energy, its final temperature was 130 degrees C. What was its initail temperature?

- Science -
**Jai**, Sunday, October 23, 2011 at 2:27am
recall that heat absorbed or released is given by

Q = mc(T2 - T1)

where

m = mass (in kg)

c = specific heat capacity (in J/kg-K)

T = temperature (in C or K)

*note: Q is (+) when heat is absorbed, and (-) when heat is released.

#1. we just substitute. the c for water is equal to 4.184 J/kg-K (you can google this or look for this in books):

Q = mc(T2-T1)

Q = 3*4.184*(10-80)

Q = -878.64 J

*note that it is negative since it cooled, and thus released heat.

#2,3 and 4: just substitute the given values and solve for the unknown. be careful with units.

hope this helps~ :)

- Science -
**Mathew Sunil**, Wednesday, September 9, 2015 at 9:53pm
7 8

## Answer This Question

## Related Questions

- Physics 20 - 1. How much heat energy is required to change 500 grams of water at...
- Physics - Please Help! I am having difficulties grasping these concepts. Explain...
- Science - How much energy is released when a 5600-g sample of water cools from ...
- Chemistry-Dr.Bob - An unknown piece of metal weighing 100. g is heated to 90.0 ...
- Science-Chemistry - A 5.00 g sample of Al pellets (specific heat = .89 J/g ...
- Chemistry - Calculate the joules of energy involved when 11 grams of water at 10...
- physics - a .300 kg piece of metal is heated to 88 degrees celsius and placed in...
- chemistry - if 150 grams of water is heated from 20 degrees C to 30 degrees C, ...
- CHEM - A 5.00 g sample of Al pellets (specific heat = .89 J/g degrees c) and a ...
- chemistry - a 100.00 mL sample of water has an initial temperature of 20.0 ...

More Related Questions