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Topic: Exam style question on solubility  (Read 2999 times)

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Offline Moronic_Acid

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Exam style question on solubility
« on: January 19, 2011, 11:40:31 AM »
Exam question on a past paper got the exam tomorrow :( i know its probably quite easy but i don't know where to start any help would be appreciated.

two solutions, each at the same temperature (298 K).
SOLUTION 1: calcium hydrogen phosphate (CaHPO4) dissolved in water;
SOLUTION 2: calcium hydrogen phosphate (CaHPO4) dissolved in a solution
already containing 0.05 M of hydrogen phosphate ions (HPO4)2–

By what factor is the concentration of calcium ions higher in Solution 1 than Solution 2,
given that the solubility product Ksp of calcium hydrogen phosphate is 2.0 x 10(–30) at 298 K?


Offline sjb

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Re: Exam style question on solubility
« Reply #1 on: January 19, 2011, 12:53:58 PM »
Exam question on a past paper got the exam tomorrow :( i know its probably quite easy but i don't know where to start any help would be appreciated.

two solutions, each at the same temperature (298 K).
SOLUTION 1: calcium hydrogen phosphate (CaHPO4) dissolved in water;
SOLUTION 2: calcium hydrogen phosphate (CaHPO4) dissolved in a solution
already containing 0.05 M of hydrogen phosphate ions (HPO4)2–

By what factor is the concentration of calcium ions higher in Solution 1 than Solution 2,
given that the solubility product Ksp of calcium hydrogen phosphate is 2.0 x 10(–30) at 298 K?



Well, for starters, what is the solubility of pure calcium hydrogen phosphate in distilled water?

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