A hot lump of 39.9 g of iron at an initial temperature of 78.1 °C is placed in 50.0 mL H 2 O initially at 25.0 °C and allowed to reach thermal equilibrium. What is the final temperature of the iron and water, given that the specific heat of iron is 0.449 J/(g⋅°C)? Assume no heat is lost to surroundings.

Answer : The final temperature of the mixture is

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

where,

= specific heat of iron =

= specific heat of water =

= mass of iron = 39.9 g

= mass of water  =

= final temperature of mixture = ?

= initial temperature of iron =

= initial temperature of water =

Now put all the given values in the above formula, we get

Therefore, the final temperature of the mixture is