Question

Determine how many joules of energy are released when 870 g of aluminum is cooled from 155celsius to 20 celsius? please help

Answer 1

This value is given by, `ms d theta` (where ,`m` is the mass or the object, `s` is its specfic heat and `d theta` =change in temperature)

Given,`m=870 gm`, `d theta=(155-20) degree C = 135 degree C`
`s` value is not given here,but it will be provided during exam.

So, heat released by this process is `870×s×135` Calorie or, `(870×s×135)×4.2` Joule i.e `493290s` Joule

Answer 2

I got `326952J`.

Explanation:

We have to use the specific heat equation, which states that

`q=mcDeltaT`

`m` is mass in kilograms

`c` is the specific heat of the object, in `J/(kg*K)`

`DeltaT` is the change in temperature, in `K`

for the specific heat of aluminium, `c=921.096 J/(kg*K)`

(source: https://www.engineersedge.com/materials/specific_heat_capacity_of_metals_13259.htm)

Plugging in the equation:

`q=0.87cancel(kg)*921.096J/(cancel(kg)*cancel(K))*408cancelK=326952.236~~326952J`