Question

) 1.3kg of gold at 300K comes in thermal contact with 2.1kg copper at 400K. The specific heats of Au and Cu are 126 J/kg-K and 386 J/kg-K respectively. What equilibrium temperature do they reach

Answer 1

Answer: Equilibrium temperature they reach is 383 K

Step-by-step explanation:

`heat_(absorbed)=heat_(released)`

As we know that,

`Q=m* c* \Delta T=m* c* (T_(final)-T_(initial))`

`m_1* c_1* (T_(final)-T_1)=-[m_2* c_2* (T_(final)-T_2)]` .................(1)

where,

q = heat absorbed or released

`m_1` = mass of gold = 1.3 kg

`m_2` = mass of copper = 2.1 kg

`T_(final)` = final temperature = ?

`T_1` = temperature of gold= 300 K

`T_2` = temperature of copper = 400 K

`c_1` = specific heat of gold =
`126J/kgK`

`c_2` = specific heat of copper =
`386J/kgK`

Now put all the given values in equation (1), we get

`1.3* 126* (T_(final)-300)=-[2.1* 386* (T_(final)-400)]`

`T_(final)=383K`

Thus equilibrium temperature they reach is 383 K