Analyzing a 1000g Graph - Melting/Boiling Points & Heat of Vaporization/Fusion

[Tokimasa]

Interpret the diagram given for 1000g if substance when heated by a 100W heater. Determine it's melting point, boiling point, and specific heat for each phase, it's heat of vaporization, and its head of fusion.

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I've analyzed the graph and found the melting point to be 60 degrees C and the boiling point to be 120 degrees C. So that part is done.

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I'm trying to use the formula c = (VI delta t) / (n delta T). But I can't come up with c. Since n is the number of moles, I know I need to figure that out. So I tried using the equation 1g = 1 N[a] (N sub a) where N[a] is 6.02E23mol^-1.

Now, I guess I need to use this formula three times (once for each phase - solid, liquid, and gas).

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I haven't started on theheat of vaporization and heat of fusion. But I don't know if there's a formula to use with this. I'm guessing it has something to do with the fact that it is the amount of energy needed to raise 1kg of a substance into a new phase.

 

[member 553083]

The specific heat for each phase is the amount of energy needed to raise 1kg of a substance by 1 degree C. So that is calculated by using the formula c = (VI delta t) / (n delta T).

 

[thepatientmental]

I will need to do more research on that.

First of all, great job on analyzing the graph and finding the melting and boiling points! To calculate the specific heat for each phase, you are on the right track with using the formula c = (VI delta t) / (n delta T). However, instead of using the equation 1g = 1 N[a] (N sub a), you can simply use the mass of the substance (1000g) as n in the formula. This will give you the specific heat for each phase.

For the heat of vaporization, you are correct in thinking that it is the amount of energy needed to raise 1kg of the substance into a new phase. The formula for this is q = m * L, where q is the heat of vaporization, m is the mass of the substance, and L is the latent heat of vaporization. This value can be found on the graph as the slope of the line between the boiling point and the point where the substance is completely in the gas phase.

Similarly, the heat of fusion can be calculated using the formula q = m * L, where L is the latent heat of fusion. This value can be found on the graph as the slope of the line between the melting point and the point where the substance is completely in the liquid phase.

I hope this helps with your calculations and understanding of the graph. Keep up the good work!