Difference between revisions of "Melting Point"

Latest revision as of 10:19, 14 December 2019

Key Stage 4

Meaning

Melting point is the temperature at which a solid can become a liquid.

About Melting Points

Different substances have different melting points.

The melting point of a substance is determined by the strength of the bonds which hold the particles in fixed positions in a solid. The stronger the bonds the higher the melting point.

When a substance is heated to its melting point it will remain at this constant temperature until all of the solid has melted.

The melting point of pure water ice is 0°C or 273 Kelvin.

Adding salt to ice can lower its melting point, causing it to melt at a lower temperature.

Transition Metals generally have very high melting points, except for Mercury which is liquid at room temperature.

Detecting Purity

The purity of a sample can be determined by observing its melting point. If the melting point is spread over a range of temperatures or different from the known values for the pure substance then the sample is not pure. For example to test if a sample of Water is pure it can be melted from Ice which should happen at exactly 0°C if it does not then it is not pure.

References

@@ Line 13: / Line 13: @@
 ===Detecting Purity===
 : The [[Pure|purity]] of a sample can be determined by [[observing]] its [[Melting Point|melting point]]. If the [[Melting Point|melting point]] is spread over a range of [[temperature]]s or different from the known values for the [[pure]] [[substance]] then the sample is not [[pure]]. For example to test if a sample of [[Water]] is [[pure]] it can be [[melting|melted]] from [[Ice]] which should happen at exactly 0°C if it does not then it is not [[pure]].
+===References===
+====AQA====
+:[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Melting points, pages 36-37, 47, GCSE Chemistry; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/019835939X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=019835939X&linkCode=as2&tag=nrjc-21&linkId=57e96876985fc39b1a3d8a3e3dc238b6 ''Melting points, pages 80-81, 84, GCSE Physics; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Melting points; alkali metals, page 26, GCSE Chemistry; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Melting points; halogens, page 28, GCSE Chemistry; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Melting points; purity analysis, pages 180-181, GCSE Chemistry; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Melting points; transition elements, page 32, GCSE Chemistry; Third Edition, Oxford University Press, AQA '']
+====Edexcel====
+:[https://www.amazon.co.uk/gp/product/1292120215/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120215&linkCode=as2&tag=nrjc-21&linkId=8f96ddb76196848bafdb124354e4cf77 ''Melting point, pages 3, 5, GCSE Chemistry, Pearson, Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Melting point; ionic compounds, page 182, GCSE Combined Science, Pearson Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120215/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120215&linkCode=as2&tag=nrjc-21&linkId=8f96ddb76196848bafdb124354e4cf77 ''Melting point; ionic compounds, page 38, GCSE Chemistry, Pearson, Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Melting point; molecular compounds, page 186, GCSE Combined Science, Pearson Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Melting points, pages 147, 149, GCSE Combined Science, Pearson Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120215/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120215&linkCode=as2&tag=nrjc-21&linkId=8f96ddb76196848bafdb124354e4cf77 ''Melting points; molecular compounds, page 42, GCSE Chemistry, Pearson, Edexcel '']
+====OCR====
+:[https://www.amazon.co.uk/gp/product/0198359829/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359829&linkCode=as2&tag=nrjc-21&linkId=90e8d7b4f039d53035238fa0320fe00b ''Melting points, pages 41, 76, 132, 134, 210-211, Gateway GCSE Chemistry, Oxford, OCR '']