Isolate the product by suction filtration and wash with COLD ethanol (remember i

Question

Isolate the product by suction filtration and wash with COLD ethanol (remember it take while to cool the ethanol so plan ahead). Continue the suction filtration for an additional 5-10 minutes to allow the product to air Weigh the crude product and determine its melting point. Recrystallize your product by dissolving it in 15 mL of ethyl acetate. Use low heat on y hot plate and stir until the entire product dissolves. Stir in 15 ml. of 95% ethanol and ret from heat. Continue to stir constantly until crystals begin to form. Collect the crystals by suction filtration and allow to air dry for 5-10 minutes Data Amount of benzaldehyde used Amount of acetone used Theoretical yield of dibenzalacetone Results Yield of purified product

Explanation / Answer

For the preparation of dibenzalacetone

1 mole of acetone reacts with 2 moles of benzaldehyde

moles of benzaldehyde = (5.25 ml x 1.045 g/ml)/106.12 g/mol = 0.0517 mols

moles of acetone = (1.43 ml x 0.791 g/ml)/58.08 g/mol = 0.020 mols

To completely react acetone we would need = 2 x 0.02 = 0.04 mols of benzaldehyde

Since moles of benzaldehyde is in excess, acetone is the limiting reagent

Theoretical yield of dibenzalacetone

moles = 0.02 mols

mass = 0.02 mols x 234.29 g/mol = 4.686 g

Results

Yield of purified product = (experimental yield/theoretical mass) x 100

pl. note your experimental mass of product 16.04 g is not possible with 0.02 mols of acetone. 1 mole of acetone yields 1 mole of dibenzalacetone product

percent yield =

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