Heat Energy and Heat Capacity

Question

If you place 125g of aluminum in a calorimeter with 1.0kg of water and the water changes temperature by 2.0°C and the aluminum changes by -74.95°C:

a. How much heat energy has the water gained?

b. What is the specific heat capacity of aluminum?

Answer 1

The heat energy gained by water is calculated by the specific heat formula:

Q=mcΔT

mass of water in this case =1kg=1000g

the specific heat capacity of water is

c_water = 4.184jJ/g°C

ΔT in this case= 2degrees (changes in temperature are same in kelvin)

putting the values in the formula

Q= (1000g)(4.184J/g°C)(2)

= 8368J

Now we calculate the Specific heat of Aluminum.

we use the same formula, but now we modify it as:

c_aluminum = Q/mΔT

By putting the values,

c_{aluminum =-8368/(125)(-74.95ºC)}

_{= 0.893J/gºC}