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need help with 1.10 please, thanks! What volume of boiling water is needed to di

ID: 481517 • Letter: N

Question

need help with 1.10 please, thanks!

What volume of boiling water is needed to dissolve the 1.0 g of benzoic add? How much benzoic acid will crystallize after cooling to 20 Degree C? Will any salicylic acid crystals also form? Will the benzoic add be pure? Consider a sample of 1.5 g of benzoic acid contaminated with 1.5 g of acid (see Problem 1.9). What volume of boiling water is needed to dissolve the 1.5 g of benzoic how much benzoic acid wills crystals after cooling to 20 degree C? Will the benzoic add be pure?

Explanation / Answer

Solubility of benzoic acid is 0.680g/10mL at 100oC.

Volume of water required to dissolve 1.5 gm benzoic acid = 10mL *1.5g/0.680g =22.06 mL

22.06mL water is required.

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Solubility at 20oc is 0.029g/10mL

So, A 22.06 mL solution will be able to retain 0.029 g *22.06mL/10mL = 0.064 g benzoic acid at 20oC

Amount that will crystallize = 1.5-0.064 = 1.436g

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Salicylic acid also crystallize along with benzoic acid and this sample will not be pure.