CHEM 140 LAB Questions Experiment 1 acetylsalicylic acid. If 50 g of each compou
ID: 571554 • Letter: C
Question
CHEM 140 LAB Questions Experiment 1 acetylsalicylic acid. If 50 g of each compound were mixed and placed into a beaker, then a melting point taken by placing a thermometer in the beaker, what would you expect an approximate melting range to be? Why? (Hint: both are soluble in water) 1. Find and report the melting point of malonic acid, and also the melting point of 2. 3 samples named A, B, and C possess identical melting points, 236-237°C. When a 3:1 mixture ofB and C is prepared, its melting point is 190-220 C. The melting point of a 2:1 mixture A and C is 236-237°C. All melting points of the mixtures were taken in large scale in a beaker. What would you expect as an approximate melting range for a 3:1 mixture of A and C? Explain your reasoning, using what you know about mp's 3. A sample taken on a melting point apparatus was found to melt at 134.2-135.0°C. The compound is either malonic acid, or acetylsalicylic acid. Assuming availability of malonic acid and acetylsalicylic acid, as well as the sample, how would you determine if the sample was malonic acid or acetylsalicylic acid? Use only the concepts introduced in this experiment, and describe all expected observations!) When performing a melting point on a solid compound, 2 melting point determinations were made. One sample, which was 1 mm in height in the capillary, possessed a melting point of 250-251°C. The other sample was 25 mm in height. What would you expect the approximate melting point to be for this 25 mm sample, if the heating rate for both samples was 2 degrees per minute? (Hint: use algebra to solve the mp range 4. For the same solid compound as the question above, if the 1 mm sample was heated at 15° per minute on a Gallenkamp melting point apparatus, what would you expect for an approximate melting point? (Algebra may be used again!) 5.Explanation / Answer
Melting point of acetylsalicylic acid is= 408K.
The melting point of melonic acid is= 408K-410K.
Approximately, both of these melting points are equal.
But after mixing both of these solutions, the resulting solution becomes impure, so here we observe a depression in melting point.
This depression in melting point occurs due to the change in lattice energies which is in turn due to the impurity.
The melting point of the resulting mixture will be less than 408K.