Question

Pure substances and mixtures are different because mixtures:


always have exactly the same composition

have exact melting points

retain the properties of the constituents in the mixture

cannot be separated into their components by physical means

Answer 1

retain the properties of the constituents in the mixture.
mixtures do not combine chemically so they don't form anything completely new from the constituents. and so can be separated by physical means unlike pure substances
mixtures have different substance so they melt over a range of temperatures.
and pure substances combine chemically in definite proportions while we can make a mixture out in any proportions e.g orange juice

Answer 2

oh that makes more sense, thanks for explaining it also, this way i understand it for later questions.

Answer 3

yeah, you're welcome.
always think of example for it and you'll find you answer :)