Reduce Melting Temp. by applying Pressure

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Homework Help Overview

The discussion revolves around a thermodynamic problem involving the melting point of ice and the application of pressure. The original poster presents a scenario with specific values for the molar volume of ice and water, as well as the latent heat of melting, seeking to determine the pressure required to lower the melting point by 1 K.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to apply the Clausius-Clapeyron equation but expresses uncertainty about the setup of the problem. They question whether to subtract 1 from the temperature and how to solve for pressure. Other participants suggest considering definite integrals and setting limits for the temperature change.

Discussion Status

Participants are actively engaging with the problem, with some providing guidance on how to approach the integration of the equation. There is a recognition of the challenges faced by the original poster, and a supportive tone is present in the responses.

Contextual Notes

There is an indication that this problem is outside the typical scope of vapor pressure questions, which may contribute to the original poster's confusion. The discussion reflects a learning process as participants navigate the complexities of the topic.

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Homework Statement



The molar volume of ice at 273.15K and 101.33 kPa is V1=19.6 cm3
That of water V2=18.00 cm3.
Latent heat of melting of ice is L=6.0 kJ mol-1.

Find the pressure that must be applied to reduce the melting point by 1 K.

Homework Equations



Clausius-Clapeyron

\frac{dP}{dT} = \frac{L}{TΔV}

ΔV = (V2-V1)

The Attempt at a Solution



The problem I am having is fundamental, this is not the usual find vapour pressure question, which is what caught me off guard. So what I'm asking is a way to set this question up. This is where I've gotten so far.

\frac{dP}{dT} = \frac{L}{TΔV}

dP = \frac{L}{TΔV} dT

P = \frac{L log (T)}{ΔV}

L log (T) = PΔV

Log (T) = \frac{PΔV}{L}

T = exp [\frac{PΔV}{L}]

Do I subtract 1 from T and solve for P? It doesn't feel right. Or did I completely mess it up?
If so please show me the set up, I should be ok with the rest.

Thanks in advance
 
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dp = (L/Δv)dT/T

then how about computing the definite integral instead of the indefinite one?

Δp = ?
 
*Face Palm* Set limit from (T) to (T-1) I take it. Thanks
 
Ryomega said:
*Face Palm* Set limit from (T) to (T-1) I take it. Thanks

Right. And use the appropriate value of T of course.
 
Yup yup! Thanks! I feel a tad retarded for not seeing that.
 
Ryomega said:
I feel a tad retarded for not seeing that.

Don't. It's always a bit rough the first time you run into a new topic ...
 

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