# Homework Help: Question with aluminum calorimeter

1. Mar 9, 2017

### hamza2095

1. The problem statement, all variables and given/known data
There is 100g of water inside of a 50g aluminum calorimeter. After a reaction takes place the temperature of the calorimeter goes from 20 degrees celsius to 25 degrees celsius

Find the energy released by this exothermic reaction

specific heat capacity of water is 4.18 and specific heat capacity of the aluminum calorimeter is 0.91
2. Relevant equations
q=mcT

3. The attempt at a solution
I approached this question using proportions since the total mass is 150, 1/3rd of the specific heat capacity is that of aluminum and 2/3 is that of water.

q=150g(2(4.18)/3 + 0.91/3)(25-20)
=2317.5J

Is this approach correct?

2. Mar 9, 2017

### Staff: Mentor

Why do you complicate things instead of calculating separately heat absorbed by aluminum and heat absorbed by water and then summing it?

3. Mar 9, 2017

### hamza2095

Would that not also give the same answer due to bedmas? I thought of doing this but wasn't sure how to

4. Mar 9, 2017

### Staff: Mentor

The simplest thing to do:

$q=m_{H_2O}c_{H_2O}\Delta T + m_{Al}c_{Al}\Delta T = (m_{H_2O}c_{H_2O} + m_{Al}c_{Al})\Delta T$

5. Mar 9, 2017

### hamza2095

Thank you! It also gives the same answer as I got but its good to see it in simpler form.