How can you remove insoluble impurities during a recrystallization? options: 1-Hot gravity filtration. 2- Vacuum filtration 3- It is not possible.You should choose another separation method. 4- Pick out the impurities with tweezers.

Question 1. a) You think that you have isolated a substance A in the lab. It melts at 75 – 77C. Since you don’t totally trust your own laboratory techniques, you wish to prove that you have substance A. Using only melting point techniques, explain how you can prove that you actually have this substance. b) List and explain how solubility is a factor throughout crystallization/recrystallization. c)Explain aspects of melting point as it is related to substance identityand substance purity

A piece of filter paper is placed in the TLC developing chamber to: Choose one: provide a lining for the TLC plate to rest on.   help the chamber saturate with the developing solvent's vapor.   make it easier to visualize the solvent front level.   protect the TLC plate.

vacuum filtration uses suction to speed up the filtration process?

To make a 300mL of 3% NaCl, weigh ______ grams of NaCl, place in a graduated cylinder, and add water to make the total volume ______ mL. To make a 20mL of 10% NaCl, weigh ______ grams of NaCl, place in a graduated cylinder, and add water to make the total volume ______ mL. To make a 4L of 0.5% NaCl, weigh ______ grams of NaCl, place in a graduated cylinder, and add water to make the total volume ______ mL.

A student obtains 0.95 g of crude 9-fluorenone and performs a recrystallization in cyclohexane (13 mL per 1 g crude 9-fluorenone). If the student recovered 0.57 of pure 9-fluorenone, what was the percent recovery of the recrystallization? Report your answer to no decimal places. Your Answer: Answer

When using the Dumas Method....   The student filled their 400 mL beaker with 250 mL of tap water and added 2 boiling stones.  They then sat their beaker on the hot plate and clamped it in place using a metal ring attached to a ring stand. The student began heating the beaker. The student obtained a 250 mL Erlenmeyer flask from the drying rack.  It looked clean but had a few water droplets inside.   The student cut out a 3 inch by 3 inch piece of aluminum foil and found a rubber band. The student determine the mass of the Erlenmeyer flask + piece of foil + rubberband.  The mass was 68.780 g. The student used a 10 mL graduated cylinder to measure out 4.5 mL of unknown liquid.  They added their unknown liquid to the 250 mL Erlenmeyer flask.   The student covered the Erlenmeyer with aluminum foil and rubber band.   Using a paper clip, the student poked 3 holes in the top of their aluminum foil The student then clamped their flask in the water bath, that hadn't started boiling yet.   When…

Volumetric pipettes are designed to deliver a precise amount of liquid, but only if you a. submerge the end of the pipette into a solution you are delivering. b. allow the pipette to drain freely, and leave any residual solution in the pipette. c. hold the pipette at a 45 degree angle and ensure that all the liquid is delivered.

A lower and/or broader melting point range for a compound after recrystallization most likely results from ________.     insoluble impurities such as dust or lint     the material still being wet with the recrystallization solvent     the compound decomposing in the heated solvent     the compound undergoing a chemical reaction with the solvent