Melting point determination. Why take melting point? To help identify sample To help identify sample...

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Transcript of Melting point determination. Why take melting point? To help identify sample To help identify sample...

Melting point Melting point determinationdetermination

Why take melting point?Why take melting point?

To help identify sampleTo help identify sample To check purity of sampleTo check purity of sample

Filling sample holderFilling sample holder

dip the open end dip the open end of the capillaryof the capillary into dry, into dry,

powdered powdered samplesample

several times,several times, shoving more inshoving more in each timeeach time

Packing the samplePacking the sample

drop the capillarydrop the capillary (closed end down)(closed end down) through a long through a long

glass tubeglass tube several timesseveral times until sample isuntil sample is compacted at the compacted at the

bottombottom

Turn machine on, andTurn machine on, andset resistor for temp rangeset resistor for temp range

ON buttonON button indicated indicated by white arrow.by white arrow. Set dial Set dial to expected to expected

melting range melting range

How to determine the right How to determine the right settingsetting

This chart shows This chart shows heating curves heating curves at various settings. at various settings. For accurate m.p.For accurate m.p. determinationdetermination the expected m.p.the expected m.p. is on the flat is on the flat part of the curvepart of the curve

Taking m.p.Taking m.p.

Turn onTurn on the digitalthe digital thermometerthermometer

Taking m.p.Taking m.p.

insertinsert up to 3up to 3 samplessamples

Wait forWait for and watchand watch samples melt.samples melt. RecordRecord melting rangemelting range