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# GCSE science question help? watch

1. What mass of iron(II) sulfate would be needed to provide 28 grams of iron?
Remember to give the unit.

Relative atomic masses: O = 16; S = 32; Fe = 56.
Relative formula mass for this FeSO4 = 152

Can some one pls tell me step by step how to do it
thanks =) x
2. mol = mass / Mr
so mol Fe = 28/56 = 0.5

therefore

mass = mol x Mr = 0.5 x 152 = 76grams

(This is what i'd do, it might be wrong in which case - sorry )
3. you are right btw
hahaha i knew what the answer was but i didn't know how to solve it tbh
its the techer who didnt explain how to do it properly
thanks x

(Original post by TwirlGirl)
mol = mass / Mr
so mol Fe = 28/56 = 0.5

therefore

mass = mol x Mr = 0.5 x 152 = 76grams

(This is what i'd do, it might be wrong in which case - sorry )
4. (Original post by zahir27)
you are right btw
hahaha i knew what the answer was but i didn't know how to solve it tbh
its the techer who didnt explain how to do it properly
thanks x
phew it wouldn't have boded well if i was wrong..got an A2 chemistry exam next week
5. haha well good luck then
I got mine tommorow
so doing some hardcore revision ahaha

(Original post by TwirlGirl)
phew it wouldn't have boded well if i was wrong..got an A2 chemistry exam next week
6. The method I use is to:

56/56 = 1

152/56 = 2.71428...

Then 2.71428... X 28 = 76g
7. Now this is even more easier ahaha
thanks x

(Original post by MrMonopoly)
The method I use is to:

56/56 = 1

152/56 = 2.71428...

Then 2.71428... X 28 = 76g
8. (Original post by MrMonopoly)
The method I use is to:

56/56 = 1

152/56 = 2.71428...

Then 2.71428... X 28 = 76g
That's the method I always use. My teacher used to do it the other way during lessons it just gets so confusing. This makes it a lot easier, and the questions they give us in the exam should always be able to be done without using moles.
9. (Original post by TwirlGirl)
mol = mass / Mr
so mol Fe = 28/56 = 0.5

therefore

mass = mol x Mr = 0.5 x 152 = 76grams

(This is what i'd do, it might be wrong in which case - sorry )
I can confirm this is correct. How was your exam?

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