Question

Brass is an alloy made from copper and zinc. A 0.59 kg brass sample at 90.0 C is dropped into 2.80 kg of water at 5.0 C. If the equilibrium temperature is 6.8C, what is the specific heat capacity of brass?

Answer 1

 Since no heat is lost to the surroundings, the change in thermal energy of the brass piece and the water sample have have the same magnitude: 

m_brass ∙ c_brass ∙ ∆T_brass = m_water ∙ c_water ∙ ∆T_water 

=> 

c_brass = c_water ∙ (m_water/m_brass) ∙ (∆T_water/∆T_brass) 
= 4186J/kg°C ∙ (2.8kg/0.59kg) ∙ ((6.8°C - 5°C) / (98°C - 6.8°C)) 
= 392J/kg