Obtain 1 Gram Of An Impure, Unknown Substance Solid
1. Obtain 1 gram of an impure, unknown substance solid. Make sure to stir the mixture before measuring the sample; record the mixture’s code in the data section.
2. Add approx. 25-50 mL of water and several boiling chips to a 125 mL Erlenmeyer flask and heat the water to a gentle boil using a hotplate.
3. On a second hotplate, place a 125 mL Erlenmeyer flask containing the one gram of unknown solid along with a boiling chip.
4. Using a ring clamp, slowly pour approx. 5-10 mL of boiling water into the flask containing the impure substance- does not need to be exact
5. After water is added, swirl the mixture for one minute while maintain the solution temperature on the hotplate.
6. Continue adding small amounts (3-5 mL) of boiling water until the unknown solid is fully dissolved. Make sure to swirl the …show more content…
It is important to only use the minimum amount of solvent necessary to dissolve the unknown. Too much will result in significantly decreased percent recovery at the end of the experiment.
8. Set up gravity filtration system using a short stem funnel (glass) lined with folded filter paper, covered with a watch glass and placed on top of the 125 mL Erlenmeyer flask –the flask should have a few milliliters of water so it will remain warm while using the hotplate.
It is vital that the solution remain hot during filtration. If the temperature drops, crystals will form. Before filtration moisten the filter paper with small amount of boiling water and after filtration rinse filter paper with 2-3 mL of boiling water to dissolve any crystals that may have formed
9. Remove the flak from the hotplate and allow filtrate to cool to room temperature. Once temperate is reached, check for crystal formation. If no crystals, gently scratch the inner wall of flask with a stirring rod to help induce crystals. After initial crystal formation, cool in ice bath for 5-10 minutes.
10. Collect recrystallized solid via suction filtration using a Büchner funnel and a 250 mL filter
2. Add approx. 25-50 mL of water and several boiling chips to a 125 mL Erlenmeyer flask and heat the water to a gentle boil using a hotplate.
3. On a second hotplate, place a 125 mL Erlenmeyer flask containing the one gram of unknown solid along with a boiling chip.
4. Using a ring clamp, slowly pour approx. 5-10 mL of boiling water into the flask containing the impure substance- does not need to be exact
5. After water is added, swirl the mixture for one minute while maintain the solution temperature on the hotplate.
6. Continue adding small amounts (3-5 mL) of boiling water until the unknown solid is fully dissolved. Make sure to swirl the …show more content…
It is important to only use the minimum amount of solvent necessary to dissolve the unknown. Too much will result in significantly decreased percent recovery at the end of the experiment.
8. Set up gravity filtration system using a short stem funnel (glass) lined with folded filter paper, covered with a watch glass and placed on top of the 125 mL Erlenmeyer flask –the flask should have a few milliliters of water so it will remain warm while using the hotplate.
It is vital that the solution remain hot during filtration. If the temperature drops, crystals will form. Before filtration moisten the filter paper with small amount of boiling water and after filtration rinse filter paper with 2-3 mL of boiling water to dissolve any crystals that may have formed
9. Remove the flak from the hotplate and allow filtrate to cool to room temperature. Once temperate is reached, check for crystal formation. If no crystals, gently scratch the inner wall of flask with a stirring rod to help induce crystals. After initial crystal formation, cool in ice bath for 5-10 minutes.
10. Collect recrystallized solid via suction filtration using a Büchner funnel and a 250 mL filter