A silver cube with an edge length of 2.28 cm and a gold cube with an edge length of 2.75 cm are both heated to 82.8 ∘C and placed in 111.5 mL of water at 20.2 ∘C . What is the final temperature of the water when thermal equilibrium is reached?

Solution :

Given :

length of silver cube = 2.28 cm

length of gold cube = 2.75 cm

Initial temperature = 82.8°C

Volume of silver cube is

Volume

               =    

mass of silver cube

Mass,

                = 10.5 x 11.8

                = 123.9 g

Similarly, the volume of gold cube is

Volume

               =    

mass of gold cube

Mass,

                = 19.3 x 20.79

                = 401.247 g

Now

heat lost by silver and gold cube = heat gained by water

∴

Now solving the equation

Final temperature, T = 31.27°C

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

the answer is 303.15 or 303