CALCULATING HEAT EXCHANGES
Purpose
The
purpose of this activity is to test validity of the equation Q = mcΔT
in a simple heat exchange.
Instructions
Measure the
mass 50 ml of tap water in a Styrofoam cup and record its temperature.
Mass of empty Styrofoam
cup: ________________
Mass of
Styrofoam cup and 50 mL of water: ________________
Temperature of
the water: _______________
Measure a
second mass of 50 ml of hot water in a second Styrofoam cup and record its
temperature.
Mass of empty Styrofoam
cup 2: __________________
Mass of
Styrofoam cup and hot water: ____________________
Temperature of
hot water: ____________________
Pour one sample
of water into the other and record the final temperature of the mixture.
Final temperature
of the mixture: _________________
1)
Use
the equation Q
= mcΔT
to find the heat gained by the cool water.
(Use c = 4.18 J/g-C as the specific heat of water.)
∆T
= Tmixed water – Tcold water
2) Use the
equation Q = mcΔT
to find the heat lost by the hot water.
∆T
= Thot water - Tmixed
water
3) Are these two number approximately equal? What does that say about the validity of the equation?