[hslove142331]

Picture mean is a cooling curve for one mole of a substance


Which portion of the graph corresponds to the release of the heat of vaporization?

1. Region (1).

2. Region (2).

3. Region (3).

4. Region (4).

5. Region (5).

6. None of these.

I 1,3,5... are right..


Which portion of the graph corresponds to the release of the heat of fusion?

1. Region (1).

2. Region (2).

3. Region (3).

4. Region (4).

5. Region (5).

6. None of these.

I don't know about this one.

What is the melting point of the solid?
The temperature of line 2 or 3 or 4 or 5 or non?

Please help me.. Thank you

[Unknown008]

When a substance changes state, its temperature remains constant until all (nearly all) the particles in the substance have changed in state (in fact it's all about intermolecular and inter-ionic bonding).

Since the graph shows two straight lines, the higher one is the boiling point while the lower one is the melting point.

Now, heat of vaporisation is the amount of heat which is involved during boiling/condensing and heat of fusion during melting/solidifying.

Post what you think is the answer! :)

I'm sure you'll do well.

[hslove142331]

I think line 4 is melting point.

[Unknown008]

Yes, that also means for

1. Region 2
2. Region 4
3. Region 4

As far as I was taught, I was told that heat of vaporisation is the heat required for a liquid to become a gas, hence the heat involved only in boiling.
The same goes for the heat of fusion, except it's melting here.