If you start with 172 g of water at 29 ◦ C, how much heat must you add to convert all the liquid into vapor at?
If you start with 172 g of water at 29
◦
C, how
much heat must you add to convert all the
liquid into vapor at 100
◦
C? Assume no heat
is lost to the surroundings.
Answer in units of kJ
More Questions From This User See All
Answers & Comments
Verified answer
First heat liquid H2O (Cp = 4.18 J/g K) from 29oC to 100oC...
dH = mCpdT
dH = 172 g * 4.18 J/g K * (100oC - 28oC) = 51765 J = 51.8 kJ
Then evaporate the water @100 oC...
dH evap (@100 oC) = 2676 J/g from the steam tables
172 g * 2676 J/g = 460,272 J = 460.3 kJ
So the total heat added is the sum of the sensible heat change (heating the liquid) and the latent heat change (evaporation)
51.8 kJ + 460.3 kJ = 512.1 kJ