Question

A 100 g piece of copper is at room temperature (20°C). It is then held over a flame and its temperature increases to 120°C after which it is dropped in a thermally insulated beaker which contains 200 g of oil. The specific heat of copper is 388 J/kg Ka) How much heat has the copper piece absorbed from the flame?b) Describe if and how the temperatures of the copper and the oil change after the metal was dropped in the oil.

Answer 1

We will have the following:

`Q=C\cdot m\cdot\Delta T`

a) The heat that the copper piece absoved was:

`Q=(388J/kg\cdot K)(0.1kg)(120-20+273.15)\Rightarrow Q=14478.22J`
`\Rightarrow Q=14.47822kJ`

So, the heat that the copper piece absorved was 14.47822 kJ.

b) The temperature of the copper will decrease when dropped in the oil, since the oil has a smaller energy state then the heat will disperse towards the lower energy state, thus making the copper colder and making the oil hotter. At some point the temperature of both will reach equilibrium and the temperature of the copper piece and the oil will be the same; this means the temperature of the copper piece will be lower and the temperature of the oil will be greater.