Question

Brass is an alloy made from copper and zinc. A 0.68 kg brass sample at 96.9◦C is dropped into 2.01 kg of water at 4.8◦C.

If the equilibrium temperature is 7.3◦C, what is the specific heat capacity of brass? The specific heat of water is 4186 J/kg ·◦ C .

Answer in units of J/kg ·◦ C.

Answer 1

345.24 J/kgC

Step-by-step explanation:

The heat that Brass had to expell to drop its temperature from 96.9◦C to 7.3◦C is the same heat that the Water had to absorb to raise its temperature from 4.8◦C to 7.3◦C:

QBrass = Qwater

mb*cb*ΔTb = mw * cw * ΔTw

Where mb is the mass of brass, cb is the specific heat capacity of brass, ΔTb is the change in temperature that the brass suffered, mw is the mass of the water, cw is the specific heat of water and ΔTw is the change in temperature that the water suffered.

cb =
`(mw * cw * (Tfw-Tow))/(mb*(Tob - Tfb))`

cb =
`(2.01 kg * 4186 J/kgC * (7.3C - 4.8C))/(0.68 kg * (96.9C - 7.3C))=345.24 J/kgC`