In: Chemistry
Calculate the amount of energy (in kJ) necessary to convert 517 g of liquid water from 0°C to water vapor at 192°C. The molar heat of vaporization (Hvap) of water is
40.79 kJ/mol. The specific heat for water is 4.184 J/g ·°C, and for steam is 1.99 J/g ·° C. (Assume that the specific heat values do not change over the range of temperatures in the problem.) ______kJ |
Cl = 4.184 J/g.oC
Heat required to convert liquid from 0.0 oC to 100.0 oC
Q1 = m*Cl*(Tf-Ti)
= 517 g * 4.184 J/g.oC *(100-0) oC
= 216312.8 J
Hv = 40.79KJ/mol =
40790J/mol
Lets convert mass to mol
Molar mass of H2O = 18.016 g/mol
number of mol
n= mass/molar mass
= 517.0/18.016
= 28.6967 mol
Heat required to convert liquid to gas at 100.0 oC
Q2 = n*Hv
= 28.6967 mol *40790 J/mol
= 1170538.9654 J
Cg = 1.99 J/g.oC
Heat required to convert vapour from 100.0 oC to 192.0 oC
Q3 = m*Cg*(Tf-Ti)
= 517 g * 1.99 J/g.oC *(192-100) oC
= 94652.36 J
Total heat required = Q1 + Q2 + Q3
= 216312.8 J + 1170538.9654 J + 94652.36 J
= 1481504 J
= 1482 KJ
Answer: 1.48*10^3 KJ