a kilogram of aluminum metal and a kilogram of water are each warmed to 75 degree celisus and placed in two identical insulated containers. one hour later, the two containers are opened and the temperture of each substance is measured. the aluminum has cooled to 35 degree celisius while the water has cooled only to 66 degree celsius. Explain this difference.

3 answers

The heat capacity is the reason.
1,000 g Al x 0.9 J/g*C = ??
1,000 g H2O x 4.18 J/g*C = ??
The water holds more heat than does the Al block; therefore, it takes longer for the water to cool.
Here is a site that talks more about heat capacity.
http://en.wikipedia.org/wiki/Heat_capacity
so is it 900 and 4180 is that the difference???
Yes, that is how much more heat the water holds than the Al.