A 2.5 g sample of naphthalene melting range 73.2-77.1 deg C is recrystallized and 1.8 g of purified material?

Question

melting range 79.3-80.1 degrees C are recovered. What conclusions can you draw from the melting ranges. This question is from my inorganic chemistry. I do not really understand the importance of the melting ranges. Can someone help me out.

Answer 1

an impure sample of naph ( or any organic solid ) will have a broader and lower melting range. The is a generality of organic melting points. When you recrystallize a compound you will concentrate your major component and it will be purer and will have a narrower slightly higher melting range. This should be an organic chemistry question - most inorganic chemicals are not characterized in the lab by a melting point.

Answer 2

Naphthalene Melting Point Range

Answer 3

a pure compound has a single melting point (water melts at 0 C or 32 F)

a mixture of miscible materials will often have a melting point range

the published melting point of naphthaline is 80.5 C
http://en.wikipedia.org/wiki/Naphtalene

so, absolutely pure naphthalene would melt at 80.5 C

if it were mixed with a lower melting material or the right type of other contaminant, the whole mixture would start melting at a lower temperature

so, what conclusions do you draw from the fact that when they purified the material (ending up with only 1.8 g of the original 2.5g) that the melting point of the purified material was higher and very close to that of completely pure naphthalene?

got it?
good luck
keep at it

Answer 4

24

Answer 5

narrower melting ranges = purer compound

closer to lit value = purer

when recrysatlized melt range should shrink as get rid of impurities

Answer 6

I have drawn the conclusion that maybe your gay