HELP Chemistry. energy required to heat

Question

At 1 atm, how much energy is required to heat 53.0 g H2O(s) at −22.0 ∘C to H2O(g) at 119.0 ∘C? In KJ.

Answer 1

To answer this, we need to know several constants related to the thermodynamics of the situation.

C_ice = 2.09 J/gº

C_liq = 4.184 J/gº

C_steam = 1.89 J/gº

∆H_f = 334 J/g

∆H_vap = 2260 J/g

Step 1: energy needed to raise 53 g of ice from -22º to 0º

q = mC∆T = (53.0 g)(2.09 J/gº)(22º) = 2437 J

Step 2: energy needed to melt 53 g of ice at 0º (phase change, no change in temperature)

q = m∆Hf = (53 g)(334 J/g) = 17,702 J

Step 3: energy needed to raise temperature of 53 g liquid from 0º to 100º

q = mC∆T = (53 g)(4.184)(100º) = 22,175 J

Step 4: energy needed to convert 53 g of liquid to gas (phase change, no change in temperature)

q = m∆Hvap = (53 g)(2260 J/g) = 119,780 J

Step 5: energy needed to raise temperature of 53 g steam from 100º to 119º

q = mC∆T = (53 g)(1.89 J/gº)(19º) = 1903 J

Summing all the energies, we have...

2437 J + 17702 J + 22175 J + 119780 J + 1903 J = 163,997 J = 164 kJ