1
answer
0
watching
1,024
views
11 Nov 2019
Melting Point Post Lab Q
1. What would be the effect on the observed melting point if sample were: a) too small b) too large- c) poorly packed d) heated too rapidly- 2. Some compounds sublime in the capillary and some decompose before melting. How do you determine melting point of these compounds? 3. A student was given a white solid for an unknown. Its melting point range was 119 121 °C. The student has previously worked with benzoic acid, and had observed that it was a white crystalline solid with a melting point of 122 °C. (a) Can the student conclude that the unknown is benzoic acid on the basis of her work to this? Why or why not? (b) What additional experimental work should be done to verify this compound? 4. You and your lab partner take melting points of the same sample. You observe a melting point of 101-107°C, while your partner observes a value of 110-112°C. Explain how you can get two different values with exactly the same sample. 5. An unidentified compound is observed to melt sharply at 111 °C with the vigorous evolution of a gas. The sample then solidifies and does not melt until the temperature reaches 155 °C, at which time it again melts sharply. Briefly explain these observations.
Melting Point Post Lab Q
1. What would be the effect on the observed melting point if sample were: a) too small b) too large- c) poorly packed d) heated too rapidly- 2. Some compounds sublime in the capillary and some decompose before melting. How do you determine melting point of these compounds? 3. A student was given a white solid for an unknown. Its melting point range was 119 121 °C. The student has previously worked with benzoic acid, and had observed that it was a white crystalline solid with a melting point of 122 °C. (a) Can the student conclude that the unknown is benzoic acid on the basis of her work to this? Why or why not? (b) What additional experimental work should be done to verify this compound? 4. You and your lab partner take melting points of the same sample. You observe a melting point of 101-107°C, while your partner observes a value of 110-112°C. Explain how you can get two different values with exactly the same sample. 5. An unidentified compound is observed to melt sharply at 111 °C with the vigorous evolution of a gas. The sample then solidifies and does not melt until the temperature reaches 155 °C, at which time it again melts sharply. Briefly explain these observations.
Trinidad TremblayLv2
8 Nov 2019