Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: hildebramdt on December 22, 2008, 11:19:49 PM
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The solubility of sodium carbonate in 100 g water is 25 g at 22 C. How many grams of the hydrtae Na2 CO3. 10H20 can be disolved in 100 g of water at 22 C?
1) 0 556g 2)0 762g 3)9 27g 4)67 5g 5) 81 7g 6) 117g
if you can , explain it, please
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You should express mass of anhydrous Na2CO3 and mass of water in hydrate as a function of the mass of hydrate. Then use definition of solubility.
Show your attempt!.
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Find the number of moles in Na2CO3 =mass in gms /molar mass =25/106=0.2358moles
Moles of water in 1mole of sodium carbonate =10
moles of water in 0.2358 moles of sodium carbonate =10X0.2358=2.358
mass of water in in 2.358 moles of water= 2.358 X molar mass of H2O
2.358X 18=42.45gm
mass of hydrate soluble in 100gm of H2O
=25 +42.45
=67.45gm=67.5 gms