MP/BP of Equal Mixes of 2 Subtances

[justadream]

Can someone confirm/deny?

If you have an equal mix of 2 substances:



MP wll be lower than the MP of either substance



BP will be higher than the BP of either substance (can someone explain this one)?


Also, what if you had an equal mix of 5 substances? Would the same rules apply?

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[t5Nitro]

This is correct. I remember this from my organic chemistry lab. If you want to know why, this explains it, but it isn't really applicable to the MCAT.

You don't need an equal mix either. This applies to any amount of impurity.

 

[justadream]

Right I kind of remember it in Organic lab too. But are there any exceptions? Like what if the two substances interact to form stronger intermolecular bonds (thus, making it harder to melt)?

 

[t5Nitro]

Right I kind of remember it in Organic lab too. But are there any exceptions? Like what if the two substances interact to form stronger intermolecular bonds (thus, making it harder to melt)?

Maybe, but we never learned about impurities doing that in my Ochem lab so I wouldn't worry about it for MCAT purposes.