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GCSE Chemistry Purity Q...

Hey guys,

I got this question on a worksheet (and sadly I couldn’t find the mark scheme so my next saviour is TSR woo!)

“A solid is found to have a melting point of 132°C. Explain how this data can be used to prove that the solid is impure (2 marks)”

If the melting point was over a range, I guess I could say that but I’m not sure how to approach it here...
Original post by Icosagon
Hey guys,

I got this question on a worksheet (and sadly I couldn’t find the mark scheme so my next saviour is TSR woo!)

“A solid is found to have a melting point of 132°C. Explain how this data can be used to prove that the solid is impure (2 marks)”

If the melting point was over a range, I guess I could say that but I’m not sure how to approach it here...

Say the MP value is different from the data book value hence is not pure because it is was then the mp would be the same as in the book
Reply 2
pure substances have a sharp melting point, if the substance is impure, that is a mixture of substances then each one will have its own melting point. Each will melt separately. If the mixtures of substances interact with each other in some way then the melting point will be over a range and not a sharp point.

You could compare the known mp of your substance with that in a data book and compare them
Reply 3
Original post by gogrizz123
Say the MP value is different from the data book value hence is not pure because it is was then the mp would be the same as in the book

Thanks! :smile:

Original post by scimus63
pure substances have a sharp melting point, if the substance is impure, that is a mixture of substances then each one will have its own melting point. Each will melt separately. If the mixtures of substances interact with each other in some way then the melting point will be over a range and not a sharp point.

You could compare the known mp of your substance with that in a data book and compare them

Thank you :biggrin:

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