Vapor Pressure of Liquids

2013-10-26 8:48 am

Vapor Pressure of Liquid problems

1. One version of the Clausius - Clapeyron equation is below, in a form that resembles the equation of a line, y = mx+b:

ln(P)=(-ΔHvap/R)(1/T)+C

Using the equation above, in terms of P, T, Δvap, R and C,

What should be graphed on the x-axis? ________

What should be graphed on the y-axis? ________

What does the slope of the line, m, represent? ________

What does the y-intercept of the line b, represent? ________

2. Using the slope from such a graph (as described in #1 above) write an equation or explain how you will determine the enthalpy of vaporization for a liquid.

回答 (1)

用戶4366

2013-10-26 4:41 pm

✔ 最佳答案

1. ln(P)=(-ΔHvap/R)(1/T)+C

What should be graphed on the x-axis? ___(1/T)_____

What should be graphed on the y-axis? ___ln(P)_____

What does the slope of the line, m, represent? __(-ΔHvap/R)______

What does the y-intercept of the line b, represent? ___[ Sorry! I don't know. ]___
May be it is just an integration constant. but I really don't know. If it represent something at infinite temperature, (1/T) = 0 then I just cannot figure out what is it.

2. Using experiment to find the vapour pressure of a liquid at various temperatures. Plot a graph of ln(P) vs (1/T).

slope of the graph = (-ΔHvap/R) = m

Calculate ΔHvap by
ΔHvap = -mR

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