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# Concentration of Calcium Oxalate Solution

CHEM-E3IDOF

About 80% of kidney stones are of calcium oxalate type, which forms when calcium (${ Ca }^{ 2+ }$) and oxalate (${ { C }_{ 2 }{ O }_{ 4 } }^{ 2- }$) levels in blood are too high. The solubility of calcium oxalate ($Ca{ C }_{ 2 }{ O }_{ 4 }$) is only 6.7 mg/L at 20 ${ }^{ o }C$.

To 15.0 mL of water is added 5.0 grams of calcium oxalate powder at 20 ${ }^{ o }C$.

After thorough mixing and centrifuging, what is the molar concentration of ${ Ca }^{ 2+ }$ in the resultant clear liquid at at 20 ${ }^{ o }C$?

A

$6.7\space mmol/L$

B

$6.7\space mg/L$

C

$5.2 \times { 10 }^{ -5 }\space mol/L$

D

$5.2 \times { 10 }^{ -2 }\space M$