urgent Moles (1 Viewer)

[samuelblayden]

I'm in year 11 and I need some urgetnt help about moles so can peopel please put down some things a bout moles

a no not the things on your skin or the little furry things wise guys

 

[Natzd]

hey,
i'm in yr12 n i know how much chem sucks haha but just stick with it coz it will you give a really good uai if you do well with it but anyways,
ask your teacher about moles..seriously...
my teacher helped me heaps with it but i also worked out a little 4 step trick to it -->

1. find the balanced equation
2. known -> moles
3. ratio
4. moles -> unknown eg. mass, volume
here, i'll give you an example...

what mass of ZnO can be produced from the smelting of ZnS with 20000L of O2 gas at SLC

1. FBE
2ZnS + 3O2 --> 2ZnO + 2SO2

2. known --> moles
20000/24.79 (24.79 is SLC)
= 807 moles of O2 (g)

3. RATIO
O2 : ZnO
3 : 2
807 : x
( 807/3) X 2
= 538 moles of ZnO

4. moles --> mass
mass = number moles x molar mass
538 moles of ZnO X (65.4 + 16) the molar mass of ZnO
= 43781g


i hope this can help you out
good luck

 

[samuelblayden]

thanks that was alot of help