PHYSICS QUESTION

Question

An insulated beaker with negligible mass contains liquid water with a mass of 0.270  and a temperature of 82.6  .

How much ice at a temperature of -24.0 

 must be dropped into the water so that the final temperature of the system will be 39.0  ?

Take the specific heat of liquid water to be 4190  , the specific heat of ice to be 2100  , and the heat of fusion for water to be 3.34×10⁵  .

Answer 1

Lilly B,

As before, I can only offer hints for solving a problem with no stated units.

In this case, use the law of heat exchange. Energy gained by cold body = energy lost by hot body

Since you are looking for the mass of ice, there will be three parts in which ice will absorb energy but all of it will be provided by the warm water.

1. determine the energy absorbed by mass M of ice in warming from -24 to 0 (M•specific heat capacity of ice•ΔT₁)
2. determine the energy absorbed by mass M of ice during melting (M•specific latent heat of ice)
3. determine the energy absorbed by mass M of molten ice in warming from 0 to 39.0 (M•specific heat capacity of water•ΔT₂)

add all the values from 1, 2, & 3 (your expression will be terms of 'M') and equate it to mass of water in beaker x specific heat capacity of water x change in temperature of water (82.6-39) and solve for M, the unknown mass of ice. I hope this helps. For further clarification on this or other problems, please feel free to ask me. Mr A