Question

How many joules of heat must be absorbed by 500g h2O @ 50CELCIUS to convert to steam @ 120 celcius?

Answer 1

Answer:

Q = 1267720 J

Explanation:

• Qt = QH2O + ΔHv

∴ QH2O = mCpΔT

∴ m H2O = 500 g

∴ Cp H2O = 4.186 J/g°C = 4.183 E-3 KJ/g°C

∴ ΔT = 120 - 50 = 70°C

⇒ QH2O = (500 g)(4.183 E-3 KJ/g°C)(70°C) = 146.51 KJ

∴ ΔHv H2O = 40.7 KJ/mol

moles H2O:

∴ mm H2O = 18.015 g/mol

⇒ moles H2O = (500 g)(mol/18.015 g) = 27.548 mol H2O

⇒ ΔHv H2O = (40.7 KJ/mol)(27.548 mol) = 1121.21 KJ

⇒ Qt = 146.51 KJ + 1121.21 KJ = 1267.72 KJ = 1267720 J