Homework Help: Chemistry

Posted by Sejul on Saturday, January 19, 2013 at 11:51am.

Calculate the amount (g) of each of the following salts that need to be added to a 200 mL volumetric flask to produce a 2 M solution of S.

CaSO(subscript 4)

[NH(subscript 4)subscript 2]SO(subscript 4) NOTE: the subscript 2 is outside the (NHsubscript 4)

Fe(subscript 2)[(SOsubscript 4)}subscript 3 NOTE: O has a subscript of 4, but the quantity SOsubscript 4 has a subscript of 3 outside.

Please help. I have no idea where to begin.

Chemistry - DrBob222, Saturday, January 19, 2013 at 2:48pm
I'll do the CaSO4 (btw, you help clutter the problem with the explanation of subscripts etc. It would be nice if html was convenient for subscripts but it isn't. Most of us here recognize that number appearing BEFORE the formula means it is a coefficient and numbers AFTER a symbol means a subscript. For example, 2CaSO4 means 2 mols calcium sulfate.)
You want 200 mL of 2M solution of S and the S is to come from CaSO4.

How many mols S do you want? That is M x L = 2 x 0.200 = 0.400 mols.
g S = mols x atomic mass = 0.400 x 32 = about 13 but you need to do it more accurately. (Note: you may have been taught to use S8 as elemental S; if so, use S8 at this point.)
Then we convert 13 g S (or whatever number you have) to g CaSO4. That is done by
13g S x (molar mass CaSO4/atomic mass S) = ?
I'll be glad to check you numbers for the others.
Chemistry - Sejul, Monday, January 21, 2013 at 9:40am
Dr. Bob222,

Could you please check the following?
Thank you.

CaSO4: 54.45664 g

(NH4)2SO4: 12.8264 x 132.1402/32.066 (molar mass(NH4)2SO4/atomic mass S)= 52.85608 g

Fe2(SO4)3: 12.8264 x 399.8801/32.066
(molar mass Fe2(SO4)3/atomic mass S)=
159.95204 g

Thank you again.

Answer this Question

Related Questions

chemistry - Suppose that the following solution is diluted by adding the ...
Chemistry - A 100.0 mL sample of 0.100 M formic acid, CHOOH, is titrated with 0....
Chemistry - 1.Calculate the pH of a solution prepared by mixing 20mL of the ....
Chemistry - A 30 mL sample of 0.150 M KOH is titrated with 0.125 M HClO4 ...
Chemistry - A 30 mL sample of 0.150 M KOH is titrated with 0.125 M HClO4 ...
CHEMISTRY..please help..thanks - Calculate the new molarity if each of the ...
Environmental Chemistry - Calculate the pH when the following volumes of 0.20 M ...
college chemistry - Consider the titration of a 50.0 mL sample of a 0.100 M ...
chemistry - Consider the titration of 88.0 mL of 0.150 M Ba(OH)2 by 0.600 M HCl...
Chemistry - A 30.00mL sample of 0.150M KOH is titrated with 0.125M HClO4 ...

For Further Reading

First Name:
School Subject:
Answer: