Heat of Vaporization Hv of
Water (Demonstration Lab)
Obj: Measure the Hv
Materials: See the diagram below.
Sketch by Ted Andersen, retired Physics Teacher
at Brockport High, a teacher’s teacher!
1. Mass the insulated cup, then
the cup with water; record the starting temperature (0.1oC).
2. Boil the water, bubbling
"live" steam (100oC) into the insulated cup.
3. Record the change in
temperature of the water ΔT.
4. Mass the cup with water again
to determine the mass of the condensed steam.
1. Calculate Hv
using the equation for heat loss/heat gain (Qlost)
mw c ΔT = ms Hv + ms
c ΔT where ms is the mass of the steam only
(water) (steam) (steam)
2. Determine the
% error. What are some sources of
3. Define Hv.
4. Why was it desirable to use steam at 1000C?
5. Why did we start with water at
6. Describe some practical
applications of water’s high Hv.
mass of cup_________ kg
mass of cup + water __________ kg
mass of water ______________ kg
temperature (cool) __________ oC
temperature (hot) ___________ oC
Final temperature of water ______________ oC
Condensate ______________oC, Cold water______________oC
mass of cup + water + condensate _____________
mass of condensate (steam ms) ___________
Back to the Brockport High School Science Department