question archive How much heat Q is required to change 19
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How much heat Q is required to change 19.0 g of ice at −1.00C to 19.0 g of steam at 128C ?
The heat required is the sum of all heat energy required in each phase.
Calculate heat required to change temperature of ice from -1°c to 0°c.
Using Q1=MC( ice)?T= 19g×2.09J/g°c× 1°c=39.71J
The next heat required is to change all ice to water at 0°c
Q2= m?Hf, ?Hf = 334J/g(constant)
Q2=19g×334J/g=6346J
The next heat is heat for needed to raise temperature of water to 100°c from 0°c
Q3=MC(water)?T=19g× 4.18J/g°C×100°c=7942J
The next phase is vapourization at 100°c whose heat is given by
Q4=m?Hv, ?Hv=2257J/g
Q4= 19g×2257J/g=42883J
The last phase is heat required to change temperature of steam from 100°c to 128°c
Q5=mc(steam)?T= 19g×2.09J/g°C×28°C= 1111.885J
The heat required is the sum of heat needed in all 5 phases
Q=Q1+ Q2+Q3+Q4+Q5= 58322.59J
Q=58.32kJ
Please see the attached file for the complete solution