Needs help with my homework
5 liters of water at 70˚c need to cooled to 50˚c.
Specific heat capasity of water is 4200J/kgK
Latent of heat of fusion of water is 3.34 x 10e5 J/kg
and the water density is 2000kg/m3
Q1
Determine the heat lost by the water when ice is added as the water cools to 50˚c
Ans = 420 KJ
Q2
Determine the heat required to melt the ice and raise the temp to 50˚c
Q2 = Heat needed to melt the ice and raise the temperature to 50˚C
Ans = 5.44 x 10e5m J
Q3
Determine the amount of ice to be added to the water to cools it from 70˚c to 50˚c
Since there is no heat loss to the environment, it can be concluded that
Q1=Q2
Ans = 0.772 kg
Q4 >
The question asked, if the heat to the environment is not neglected, what is the relation between the diameter of the mug and the amount of ice needed to cools 7 liters of water from 70˚c to 50˚c.
I'm stuck, I know that the relation is time, needed to cools it naturally and by adding ice but I can't find any formula to relates time in it.
Thanks in advance
