# chemistry

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At 1 atm, how much energy is required to heat 79.0 g of H2O(s) at –20.0 °C to H2O(g) at 121.0 °C?

• chemistry - ,

figure the heat to take ice to OC
mc deltatemp
figure the heat to melt the ice at OC
Heatfusion*mass
figure the heat to warm it from 0C to 100C
mc deltatemap
figure the heat to vaporize the water at 100C
Heatvaporizatioin*mass
Figure the heat to heat the steam from 100C to 121C.
mc deltaTemp

add them together.

remember, ice, water, steam all have different specific heat capacities c.

• chemistry - ,

q1 = heat to raise T solid H2O from -20 to ice at zero C.
q1 = mass H2O x specific heat ice x (Tf-Ti) where Tf = 0 and Ti = -20

q2 = heat to melt ice.
q2 = mass ice x heat fusion.

q3 = heat to raise T of liquid H2O from zero C to 100 C.
q3 = mass H2O x specific heat liquid H2O x (Tfinal-Tinitial) where Tf = 100 and Ti = 0.

q4 = heat to change liquid H2O at 100 C to steam at 100 C.
q4 = mass H2O x heat vaporization.

q5 = heat to raise steam from 100 C to 121 C.
q5 = mass steam x specific heat steam x (Tfinal-Tinitial) where Tf is 121 C and Ti is 100 C.

Total q = q1 + q2 + q3 + q4 + q5

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