posted by Help1001 .
An ice cube at 0 degrees Celsius was dropped into 30.0g of water in a cup at 45 degrees Celsius. At the instant that all of the ice was melted, the temperature of the water in the cup was 19.5 degrees Celsius. What was the mass of the ice cube?
How much heat did the water lose in going from 45 to 19.5 degrees?
Mass x specific heat water x (Tfinal-Tinitial).
How much heat did the ice gain?
mass ice x heat fusion.
heat lost + heat gain = 0.
The only unknown is mass ice.