1) Important solubility characteristics for a solvent to be used in the crystallization of an organic solid that’s contaminated with impurities is that the organic solid should have low solubility at low temperatures in the solvent, but highly soluble at high temperatures. Also, the solvent should allow the impurities to be either completely soluble or completely insoluble at all temperatures.
2) One way to improve our percent recovery is by making a second crop of crystals by removing the solvent from the mother liquor, or crystallization filtrate, and then recrystallizing the resulting solid. One other way to minimize lost product is by placing our flask on a hot plate to preheat and keep it on there while the hot solution is being gravity …show more content…
Since B is less soluble in lower temperatures of toluene, then we must find the minimum amount of toluene in this condition to keep it completely dissolved, which is 200ml of toluene. Next, we need to make sure all 19g of A will be completely soluble at the high temperature (110 C) in 200ml of toluene, which it is, so that makes 200ml of toluene the correct amount. Since some of A is still soluble at low temperatures (20 C) of toluene, there will be some lost product. Now, we just subtract the amount of dissolved A in the cold temperature of toluene from our initial 19g of A to get the amount …show more content…
Also, heating too fast can cause a heat lag, where the crystals aren’t heated to the same temperature as the thermometer, causing an inaccurate melting point
2) One way to improve our percent recovery is by making a second crop of crystals by removing the solvent from the mother liquor, or crystallization filtrate, and then recrystallizing the resulting solid. One other way to minimize lost product is by placing our flask on a hot plate to preheat and keep it on there while the hot solution is being gravity …show more content…
Since B is less soluble in lower temperatures of toluene, then we must find the minimum amount of toluene in this condition to keep it completely dissolved, which is 200ml of toluene. Next, we need to make sure all 19g of A will be completely soluble at the high temperature (110 C) in 200ml of toluene, which it is, so that makes 200ml of toluene the correct amount. Since some of A is still soluble at low temperatures (20 C) of toluene, there will be some lost product. Now, we just subtract the amount of dissolved A in the cold temperature of toluene from our initial 19g of A to get the amount …show more content…
Also, heating too fast can cause a heat lag, where the crystals aren’t heated to the same temperature as the thermometer, causing an inaccurate melting point