Alan wants to identify an unknown solid compound. Which statement correctly describes a method he could use to identify the compound?

A: he could find the temperature at which the compound melts because pure substances have definite melting points

B: he could find the mass of the sample because pure substances have definite masses

C: he could use a mesh screen to filter out the different elements that make up the compound

D: he could melt the compound because melting allows the elements of a compound to seperate