# Gcse mole questions help!?!?!?

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#1
1) H2 + Cl2 > 2HCl
a) when two moles of hydrogen gas react, what mass of HCl is produced?
b) When two moles of hydrogen gas react, what mass of chlorine gas reacts?

c) 3H2 + N2 > 2NH3
when one mole of hydrogen gas reacts, what mass of NH3 is produced?
d) when two moles of hydrogen gas react, what mass of N2 reacts?

e) C2H50H +302 > 2CO2 + 3H20
when 200g of ethanol is burned, what mass of CO2 is produced?
f) what mass of ethanol will produce 54g of water?
g) what mass of ethanol will produced 100g of water?

h)2Fe +3Cl2 > 2FeCl3
what mass of iron chloride would be produced from 0.5 moles of iron?
i) when 100g of iron reacts, how many moles of chlorine reacts?
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Okay, so for a-d, I did ratio to figure it out.
For e-g I just did conservation of mass and relative formula mass
And I'm stuck on H and I. Any help please? Much appreciated.
I'm also not sure if I did a-e right so if my methods seems wrong, feel free to point that out.
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6 years ago
#2
Start by using the equation:
mass = Mr * moles (you may/may not need to rearrange this)
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#3
(Original post by surina16)
Start by using the equation:
mass = Mr * moles (you may/may not need to rearrange this)
So for the first question I would do 4 moles multiplied by 36.5g?
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6 years ago
#4
(Original post by Sakura-Sama)
So for the first question I would do 4 moles multiplied by 36.5g?
I think so, but not 100% sure
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6 years ago
#5
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#6
(Original post by surina16)
I think so, but not 100% sure
Thanks, but what about the last two question? You can't use that method I think
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6 years ago
#7
Remember Moles = Mass/Mr

Also, use the ratios in the equations!
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#8
WOW ITS AMAZING I THINK I FOUND THE ANSWER TO EVERYTHING THANK YOU
not. -.-
1
6 years ago
#9
(Original post by Sakura-Sama)
Thanks, but what about the last two question? You can't use that method I think
for h I think you just work out the Mr of iron chloride, and since the ratio is 2:2, it is also 0.5:0.5, and so I think you halve the Mr to get your result?
(since you would have your Mr and multiply it by 0.5 moles)
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#10
(Original post by Gogregg)
Remember Moles = Mass/Mr

Also, use the ratios in the equations!
I don't think you can use that method for questions e-i, what do you think?
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6 years ago
#11
(Original post by Sakura-Sama)
Thanks, but what about the last two question? You can't use that method I think
for I, you want to work out how many moles of iron you have (using the rearranged formula) when you have 100g and the Mr (56).
work this out, and then go from there using ratios
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6 years ago
#12
(Original post by Sakura-Sama)
Thanks, but what about the last two question? You can't use that method I think
e) for every molecule of ethanol... 2 molecules of CO2 are released
work out the moles of ethanol (mass/Mr) and then double it to get moles of CO2
and then mass = MrMol

i think

f) work out moles of water using moles = mass/ Mr and since 3H2O s are made for every one molecule of ethanol you divide it by 3 to get the moles of ethanol and then again mass = Mr Mol

g)same as above just mass is different

h) 1:1 mole ratio of Fe to FeCl3
so moles of FeCl3 is also 0.5
and then mass = Mr Moles

moles ratio of Fe and Cl2 = 2:3 so
use moles = Mass/ Mr to find moles of Fe and then divide them by 2 to get 1 moles and times it by 3 to get moles of Cl2 reacting

that's what I think anyway :3

if it's all wrong dont blame me x'D
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#13
(Original post by surina16)
for h I think you just work out the Mr of iron chloride, and since the ratio is 2:2, it is also 0.5:0.5, and so I think you halve the Mr to get your result?
(since you would have your Mr and multiply it by 0.5 moles)
OOOOOH good idea!
Thanks! I think I got it
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6 years ago
#14
(Original post by Sakura-Sama)
OOOOOH good idea!
Thanks! I think I got it
no problem! (I hope )
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6 years ago
#15
(Original post by Sakura-Sama)
I don't think you can use that method for questions e-i, what do you think?
You can use them!
e) C2H50H +302 > 2CO2 + 3H20
when 200g of ethanol is burned, what mass of CO2 is produced?
mass = 200, you can work out the mr, and using the ratio (1:3) and the mr (18) to work out the mass.

you can use this method for the rest of the questions
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#16
(Original post by z33)
e) for every molecule of ethanol... 2 molecules of CO2 are released
work out the moles of ethanol (mass/Mr) and then double it to get moles of CO2
and then mass = MrMol

i think

f) work out moles of water using moles = mass/ Mr and since 3H2O s are made for every one molecule of ethanol you divide it by 3 to get the moles of ethanol and then again mass = Mr Mol

g)same as above just mass is different

h) 1:1 mole ratio of Fe to FeCl3
so moles of FeCl3 is also 0.5
and then mass = Mr Moles

moles ratio of Fe and Cl2 = 2:3 so
use moles = Mass/ Mr to find moles of Fe and then divide them by 2 to get 1 moles and times it by 3 to get moles of Cl2 reacting

that's what I think anyway :3

if it's all wrong dont blame me x'D
All of your methods came to the answers I got, THANK YOU SO MUCH
*HUGS*
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#17
(Original post by Gogregg)
You can use them!
e) C2H50H +302 > 2CO2 + 3H20
when 200g of ethanol is burned, what mass of CO2 is produced?
mass = 200, you can work out the mr, and using the ratio (1:3) and the mr (18) to work out the mass.

you can use this method for the rest of the questions
THANK YOU SO MUCH I TOTALLY GET IT NOW
1
6 years ago
#18
(Original post by Sakura-Sama)
THANK YOU SO MUCH I TOTALLY GET IT NOW
0
6 years ago
#19
(Original post by Sakura-Sama)
All of your methods came to the answers I got, THANK YOU SO MUCH
*HUGS*
No problem *hugs*
would be pretty embarrassing to get them wrong since I'm an A2 chemistry student x'DDD
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6 years ago
#20
H is experimental masses

You begin by listing the formula masses of the elements you need in this case you need 2Fe and 2FeCl3 so

2Fe -> 2FeCl3
110. 216.5

0.5 moles of iron is 27.5 so 110/27.5 = 4
110. 216.5
Divide both by 4

27.5. 54.125

So 54.125g is produced
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