The percentage of water of crystallization in ZnSO\(_4\).7H\(_2\)O is?
[Zn = 65, S = 32, O = 16, H = 1]
molar mass of water [7H\(_2\)O] = 7[ 2 * 1 + 16] → 7 * 18 = 126g/mol
molar mass of ZnSO\(_4\).7H\(_2\)O = [65 * 1] + [32 * 1] + [16 * 4] + 7[ 2 * 1 + 16]
→ 65 + 32 + 64 + 126 = 287g/mol
percentage of water of crystallization = \(\frac{mass of water of crystallization}{mass of hydrated compound} * 100%\)
→ \(\frac{126}{287} * 100\) = 43.9
≈ 44%
There is an explanation video available below.
Contributions (13)
4 years ago
Then u find the molar mass
{65+32+(16x4)}+7[(1x2)+16]
Molar Mass of 7H2O is 126
ND molar mass of ZnSO4 is 161
ZnSO4.7H2O
(161)+(126)=287
Since you're looking for the percentage of water....
126 100
------ x ----- = 43.9% approximately 44%
287 1
1 year ago
Basically, just find the mass of the whole substance, and find the mass of the water.
Then do Mass of water/Mass *100
1)
Mass of whole substnace = 65g + 32g + (16*4)g + [7(2 +16)]g
Mass of whole substance = 287g
2)
Mass of water = 7 * (2 +16)
Mass of water = 126g
3)
Percentage = 126g/297g * 100
Percentage = 43.902%
Percentage = 44% (2 S.f)
Done!
6 years ago
Zn = 65 S= 32 O = 16 H=1
The expected moelcular formula formula for the compound will be ZnSO .7H O which satisfy the molecular mass 287 g/mol. It is known as white vitriol.
The formula can also be derived by using empirical formula concept.
ZnSO .7H O contains seven water molecule in whose molecular mass is 126 (7x18).
The percentage of hydrogen present in water molecules is = (14 x100) / 126
= 11.11 %
% of water crystal in compound = (126 x 100) /287
= 43.90 %...approximately 44%
10 years ago
3 years ago
molar mass of ZnSO4.7H2O = [65 * 1] + [32 * 1] + [16 * 4] + 7[ 2 * 1 + 16]
→ 65 + 32 + 64 + 126 = 287g/mol
percentage of water of crystallization = massofwaterofcrystallizationmassofhydratedcompound∗100
→ 126287∗100 = 43.9
≈ 44%
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