Essay About Identification Of An Unknown Solid And B. Melting Point Of Unknown

Identification Of An Unknown Solid By Melting Point
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ÐҐÐo. Summary of Results
A. Melting point of Benzoic Acid
Temperature (ÐЎД†C)
Observation
Unmelted
White salt
First liquid appear point
Grainy and shiny white
Becoming all liquid
Clear
B. Melting point of unknown #42
1st trial
Temperature (ÐЎД†C)
Observation
Unmelted
Shiny light yellow crystal
First liquid appear point
Grainy yellow
Becoming all liquid
Clear
2nd trial
Temperature (ÐЎД†C)
Observation
Unmelted
Shiny light yellow crystal
First liquid appear point
Grainy yellow
Becoming all liquid
Clear
C. Melting point of mixture (Unknown + Benzil)
Temperature (ÐЎД†C)
Observation
Unmelted
Shiny light yellow crystal
First liquid appear point
Grainy yellow
Becoming all liquid
Clear
ÐҐб. Discussion of results
Assessment of sample purity for a known substance. By comparing observed range for an actual sample to the known range for a pure sample, I can tell whether my actual sample is pure or contaminated (the range is depressed and broadened). So, In part A, melting point of benzoic acid was observed in range 122 to 125 ÐЁЬC. By comparing melting point of benzoic acid (121 ÐЁЬC) with result from part A, the result is little higher than the pure melting point. So I can tell it is little contaminated.

Identification of an unknown sample (compare its observed melting range with known compounds). Unknown #42 was found to have a melting range of 99 to 101 ÐЁЬC in 1st trial and 95 to 97 ÐЁЬC in 2nd trial. The only one given pure compounds with similar melting ranges was benzil (94~95 ÐЁЬC). The mixture of the unknown and benzil produced