posted by john on .
5) An insulated Thermos contains 190 cm3 of hot coffee at 79.0°C. You put in a 11.0 g ice cube at its melting point to cool the coffee. By how many degrees (in Celsius) has your coffee cooled once the ice has melted and equilibrium is reached? Treat the coffee as though it were pure water and neglect energy exchanges with the environment. The specific heat of water is 4186 J/kg•K. The latent heat of fusion is 333 kJ/kg. The density of water is 1.00 g/cm3.
Are you supposed to assume that the ice is intially 0 C? It could be lower.
The heat gained by the 11 g of ice, as it melts and rises to final temperature T, is equal to the heat lost by the 190 g of original liquid water, as it cools from 79 C to T.
Write that as an equation and solve for T. .
but i cant do it!!!
Change all the temp. to Kelvin first. Ice is 0C in solid form so there is a latent heat too.
4187(190/1000)(352-T)=333x1000x11/1000 + 4187(11/1000)(T-273)
Solve for T?
Then (T-273) is in Celsius.
Difference = 79 - (T-273)
The answer is 79.909 degrees C, but don't know how to get that