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#heat of vaporization

3 public questions tagged with this topic.

Work Heat Distinction and Energy Transfer Modes

How much heat is required to vaporize 0.9 g of water at 100^circ C and 1 atm ? (Latent heat = 2256 J/g )

**Work and heat** both energy transfer modes, work organized, e.g., lifting weight, compressing gas, electrical current, heat random due to temperature difference, work can be completely converted to heat via friction, but heat cannot be completely converted to work (second law), energy transfer modes include work (mechanical, electrical) and heat (conduction, convection, radiation). Δ Q = m L . m = 0.9 , L = 2256 . Δ Q = 0.9 × 2256 = 2030.4 J ≈ 2030 J . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal W = n R T ln(V₂/V₁),

Ref: NCERT > Physics Book > Thermodynamics > Work Heat Distinction and Energy Transfer Modes

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Heat Transfer Work Distinction and Internal Energy Change

How much heat is required to vaporize 2 g of water at 100^circ C and 1 atm ? (Latent heat = 2256 J/g )

**Heat and work distinction** heat is energy transfer due to temperature difference, random molecular motion, work is organized energy transfer due to macroscopic force, e.g., piston movement, both path functions depend on process, not state, internal energy U state function depends only on state (T for ideal gas), ΔU path independent, Q and W path dependent but Q-W = ΔU path independent. Δ Q = m L . m = 2 , L = 2256 . Δ Q = 2 × 2256 = 4512 J . Using first law ΔU = Q - W, W = ∫ P dV, isobaric W = P ΔV, isothermal

Ref: NCERT > Physics Book > Thermodynamics > Heat Transfer Work Distinction and Internal Energy Change

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