Question

An iron piston in a compressor has a mass of 3.62 kg. If the specific heat of iron is 0.449 J/g°C, how much heat is required to raise the temperature of the piston from 12.0°C to 111.0°C?

I got Q=3620(4.184)(99) which equals 160.91 but the answer is 1.61x10^5. Where did I go wrong?

Answer 1

`DeltaE=1.61*10^5J`

Explanation:

`DeltaE=mcDeltatheta`, where:

• `DeltaE` = change in energy (`J`)
• `m` = mass of the object (`kg`)
• `c` = specific heat capacity of the object (`J` `kg^(-1)` `K^(-1)`)
• `Deltatheta` = change in temperature (`K`)

`0.449J` `g^(-1)` `""^circC^(-1)` `= 449J` `kg^(-1)` `K^(-1)`

`Deltatheta = 111-12=99^circC`

As `Delta""^circC=DeltaK`

`Deltatheta=99K`

`DeltaE=3.62*449*99=160912.62J=1.6091262*10^5J~~1.61*10^5J`