measuring melting point

Question 1

does the heating oil need ro have a higher or lower boiling point than the sample?

Answer 1

higher

Question 2

does the heating oil need ro have a higher or lower flammability than the sample?

Answer 2

higher

Question 3

one way of determining the degree of purity

Answer 3

determine the melting

“point”, or melting range,

Question 4

what kind of melting point wold you expect if the sample was pure?

Answer 4

If the sample is very pure then the melting point will be a

sharp one, at the same value as quoted in data books.

Question 5

how do impurities (including the solvent from the recrystallsation process affect melting point)

Answer 5

the melting point will be lowered and

the sample will melt over a range of several degrees Celsius

Question 6

how do you verify the degree purity

Answer 6

Comparing an experimentally determined melting point

value with one quoted in a data source

Question 7

possible errors?

Answer 7

Sometimes an error may occur if the temperature on the thermometer is not the same as the temperature in
the actual sample tube.

Question 8

two methods of melting point

Answer 8

Melting point can be measured in an electronic melting point
machine

or using a practical set up where the capillary tube is
strapped to a thermometer immersed in some heating oil.

In both cases a small amount of the salt is put into a capillary tube.