What variables effect the accuracy of a coffee cup calorimeter? Please explain.?

Question

I need to know a few, and how they affect the accuracy of the specific heat of a reaction. Thanks...

Answer 1

A calorimeter is affected by the environment outside. For a calorimeter to be more accurate, it has to be perfectly insulated. A coffee cup wont insulate it perfectly.

Answer 2

A coffee cup calorimeter has a very high heat capacity, it is not a perfect insulator, therefore some heat goes into the cup and is transferred to the surroundings.  Some heat is lost to the environment at the surface of the water.  Some heat is lost to the thermometer, and heats the thermometer  up.  Some heat could even be lost through the bottom of the cup to the lab bench.  (I have my students place the coffee cups in a 250 or 400 mL beaker.  That is primarily for stability, but it does insulate the cup from the benchtop.)