Summer chem help por favor!

Question

5. Which of the following actions would be likely to change the boiling point of a sample of a pure liquid in an open container?

I Placing it in a smaller container

II Increasing the number of moles of the liquid in the container

III Moving the container and liquid to a higher altitude

a. I only

b. II only

c. III only

d. II and III only

e. I, II and III

Answer 1

A liquid boils when its vapor pressure exceeds the ambient pressure.  Vapor pressure is only dependent upon the liquid being used and the temperature of the liquid (vapor pressure increases with temperature).  Thus, changing the amount of liquid or the container size does not affect vapor pressure or ambient pressure.

Moving the container to a higher altitude decreases the ambient pressure, making the liquid boil at a lower temperature, so the answer is c.

Answer 2

I would think only III.

Think about boiling water.  Even if you boil water in a smaller kettle, the water will still boil at 100 degrees Celsius.  Same thing if you added more water into the kettle.

Remember that the boiling point of water changes with altitude.  It boils at 100 degrees Celsius at sea level (or 1 atm).  However, if we went up to Mount Everest and boiled water there, the boiling point would be lower, so cooking an egg on Mt. Everest would take longer than it would say at your house.

[Answer: see above]