Apiece of glass with a mass of 32.50 g specific heat of 0.840 j/g*°c and an initial temperature of 115 °c was dropped into a calorimeter containing 57 g of water (specific heat 4.184 j/g*°c). the final temperature of the glass and water in the calorimeter was 119.2 °c. what was the initial temperature of the water?

39.84°c
79.68°c
119.84°c
139.68°c

Answer : The final temperature of water is,

Solution :

As we know that,  

         .................(1)

where,

= mass of glass = 32.50 g

= mass of water = 57 g

= final temperature  of water and glass =

= initial temperature of water = ?

= initial temperature glass =

= specific heat of water =

= specific heat of glass =

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

Therefore, the final temperature of water is,