[babiixswt]

AH, we're doing complete review in school right now.
I don't know why, but my mind is BLANK. I forgot EVERYTHING.
I just need a tiny bit of a helping hand.

1) What happens to the heat energy that must be used to melt a solid?
(Recall that the temperature does not change during melting).

2) How does air inside a balloon hold the rubber out?
That is, what causes the pressure?

3) Why does decreasing the pressure lower the boiling point of a liquid?

4) Explain how aintifreeze raises the boiling point of water.

5) The air pressure inside an automobile tire increases when the tire becomes
warm. Why is this so?

I'm not asking for answers here.
but merely explanations or any sort of a lending helping hand you can give me.
I'm completely stuck.

AH I missed one

6) Explain how substances like salt and ethylene glycol lower the freezing point of water.

[skadoosh!]

1) the heat is in the molecules; like, the movement of the molecules in a liquid is faster than a solid, so the heat is actually in the molecules.
for numbers 2 and 5, think of the kinetic energy and speed of the molecules (similar to number one)

[alicimoo]

5) The air pressure inside an automobile tire increases when the tire becomes
warm. Why is this so?
When the tire becomes warm, the temperature inside increases. When the temperature increases, the air molecules move more and take up more space. Since the volume of air increases inside, and there is no way for the air to escape, the pressure increases.

(Pressure x Volume) / Temperature = constant number <-- Gas Law

Sorry, I took chemistry 2 years ago so I don't really remember much of the stuff so I can't help you with anything else. =/

[GazelMa]

4) The density of the solution increases thus the boiling point increases as well.

[mkayimcherry]

My gut is saying that number 3 has to do with the ideal gas law (PV=nrT) although I'm not entirely sure =/

So higher pressure leads to a higher temperature if volume and number of moles of gas are constant.

The opposite would be lower pressure would lead to a lower boiling point.

[NguyenQ]

3) Why does decreasing the pressure lower the boiling point of a liquid?

Just know the meaning of boiling point. Boiling point is where the vapor pressure equals the atmospheric pressure/surrounding pressure. As you lower the atmospheric pressure it lowers the amount of energy required to make the vapor pressure equal that of the atm pressure.

4) Explain how aintifreeze raises the boiling point of water.

You're adding something that lowers the vapor pressure of water. So it requires a higher temp to bring up the vapor pressure to equal that of it surrounding temp.

Look up "Boiling Point Elevation"

[babiixswt]

AH I missed one

6) Explain how substances like salt and ethylene glycol lower the freezing point of water.