Melting Point Lab

Topics: Salicylic acid, Temperature, Chemical compound Pages: 3 (653 words) Published: May 11, 2012
Melting Point Determination and Thermometer Calibration Lab

The melting point of a substance, a solid in this case, signifies the temperature at which the first crystal starts to melt until the temperature at which the last crystal disappears is reached. That being said, melting points are expressed in ranges, am organic compound will have a sharp range depending on the purity of the compound. Impurity of an organic substance will register an abnormal melting point based on its expected propensity observed, this will cause the temperature range to widen. Using this hypothesis, mixed melting point technique could determine if the unknown compound added to the mixture causes a temperature depression, if not, the unknown is likely to be the same as your starting compound. Results:

Melting Point:
Compound| Experimental (°C)| Lit value (°C)|
Ice-water| 2°C| 0°C|
Naphthalene| 81-83°C| 80-82°C|
Acetanilide| 113-116°C| 113-115°C, 128-129°C|
Acetylsalicylic acid| 136-140°C| 135-140°C|
Salicylic acid| 159-162°C| 158-160°C|
Succinic acid| 186-188°C| 185-189°C|

Compound Structure:
Naphthalene| Acetanilide|
Acetylsalicylic Acid| Salicylic acid|
Succinic acid| Water|
Eutectic Point Determination: Melting Point
Compound | Experimental| Lit value|
Urea| 131-134°C| 132.7°C +/- 1|
Trans-cinnamic acid| 134-137°C| 135°C +/-1|

Mixture Melting Points:
Urea| Trans-cinnamic acid| Experimental °C|
4| 1| 115-125°C|
2| 1| 101-115°C|
1| 1| 72-115°C|
1| 2| 108-117°C|
1| 4| 106-115°C|

Unknown #2: Araya
Melting Point (experimental)| Compound| Lit Value|
116-121°C| Benzoic Acid| 121.5-122°C|

Unknown #53: Chanel
Melting Point (experimental)| Compound| Lit Value|
155-159°C| Salicylic acid| 158-160°C|


The melting points in part A of the lab had the experimental values for the compounds that were within +/-2°C of the lit values. This...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Melting Point Essay
  • Melting Point Essay
  • Essay about Freezing point and melting point
  • Lab Report 1-The Testing of the Melting Points of p-dichlorobenzene and naphthalene Essay
  • Melting Point Essay
  • Melting Point Essay
  • Essay on Mixed Melting Points
  • Melting Point Essay

Become a StudyMode Member

Sign Up - It's Free