Podcast Beta
Questions and Answers
What is the purpose of adding charcoal during the purification process with low grade benzoic acid?
Why is the solution containing the charcoal heated to boiling with frequent stirring?
What is the purpose of dividing the filtrate into two Erlenmeyer flasks during the purification process?
Why is it important to wash the crystals with a small amount of cold water?
Signup and view all the answers
What should be done if drying of crystals is not completed in one lab session?
Signup and view all the answers
Why is it advised to add the solvent in small portions while dissolving the solid in an Erlenmeyer flask?
Signup and view all the answers
What is the purpose of dividing the filtrate into two Erlenmeyer flasks during the purification process?
Signup and view all the answers
Why is it advised to add the solvent in small portions while dissolving the solid in an Erlenmeyer flask?
Signup and view all the answers
What should be done if drying of crystals is not completed in one lab session?
Signup and view all the answers
Why is the solution containing charcoal heated to boiling with frequent stirring?
Signup and view all the answers
In recrystallization, what is the purpose of washing the crystals with a small amount of cold water?
Signup and view all the answers
What is the role of adding charcoal during the purification process with low grade benzoic acid?
Signup and view all the answers
Why should the funnel be kept hot during filtration in recrystallization?
Signup and view all the answers
What happens when the solution containing charcoal is heated to boiling?
Signup and view all the answers
What does comparing the appearance of crystals in two Erlenmeyer flasks help determine?
Signup and view all the answers
Under what condition should one flask be set aside to cool slowly without disturbance?
Signup and view all the answers
Study Notes
Purification of Low Grade Benzoic Acid by Recrystallization
- Recrystallization is a common method for purifying solids, involving several steps.
Steps in Recrystallization
- Dissolve 1.0 gram of low grade benzoic acid in a minimum amount of boiling water (approximately 75 mL) in a 125 mL Erlenmeyer flask.
- Add a small amount of solvent at a time to avoid excess.
- Add charcoal to remove colored impurities, heat to boiling point, and stir frequently.
- Filter the solution while hot through fluted filter paper into a heated Erlenmeyer flask containing 5 mL of water.
- Ensure the funnel is hot to prevent crystallization on the funnel.
Crystallization and Filtration
- Divide the filtrate into two Erlenmeyer flasks.
- Set aside one flask to cool slowly without disturbance to allow crystallization to take place.
- Place the other flask in an ice bath.
- Compare the appearance of the crystals in the two flasks.
- Combine the two solutions and filter the crystals.
- Wash the crystals with a small amount of cold water to remove the adhering mother liquor.
Drying the Crystals
- Spread the crystals on a watch glass and allow to dry.
- If drying is done overnight, cover the crystals with a filter paper and keep in a locker until the next laboratory period.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about the common method of purifying solids through recrystallization involving specific steps like dissolving the solid in a suitable solvent and removing impurities. This quiz focuses on the purification process of low grade benzoic acid.
