Reduce Melting Temp. by applying Pressure

In summary, the conversation discusses the use of the Clausius-Clapeyron equation to find the pressure required to reduce the melting point of ice by 1 K. The equation involves the latent heat of melting, the molar volume of ice and water, and the change in temperature. The conversation also touches on using a definite integral to solve the problem.
  • #1
Ryomega
67
0

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

[itex]\frac{dP}{dT}[/itex] = [itex]\frac{L}{TΔV}[/itex]

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.

[itex]\frac{dP}{dT}[/itex] = [itex]\frac{L}{TΔV}[/itex]

dP = [itex]\frac{L}{TΔV}[/itex] dT

P = [itex]\frac{L log (T)}{ΔV}[/itex]

L log (T) = PΔV

Log (T) = [itex]\frac{PΔV}{L}[/itex]

T = exp [[itex]\frac{PΔV}{L}[/itex]]


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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  • #2
dp = (L/Δv)dT/T

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

Δp = ?
 
  • #3
*Face Palm* Set limit from (T) to (T-1) I take it. Thanks
 
  • #4
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.
 
  • #5
Yup yup! Thanks! I feel a tad retarded for not seeing that.
 
  • #6
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 ...
 

1. How does pressure affect the melting point of a substance?

Applying pressure can decrease the melting point of a substance by compressing its particles and reducing the space between them. This makes it easier for the particles to overcome the intermolecular forces and transition into a liquid state.

2. Can all substances have their melting point reduced by applying pressure?

No, not all substances are affected by pressure in the same way. Some substances, such as water, have a unique property where their melting point actually increases with an increase in pressure.

3. What is the relationship between pressure and melting point?

The relationship between pressure and melting point is inverse. This means that as pressure increases, the melting point decreases, and vice versa.

4. How much pressure is needed to reduce the melting point of a substance?

The amount of pressure needed to reduce the melting point varies depending on the substance. Generally, a higher pressure is needed for substances with stronger intermolecular forces.

5. Are there any other factors that can affect the melting point of a substance?

Yes, in addition to pressure, the melting point of a substance can also be affected by factors such as impurities, the presence of other substances, and the rate of heating or cooling. These factors can alter the intermolecular forces and therefore, change the melting point.

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