# chemistry help

#1
Gold reacts with the elements in group 7 of the periodic table. 0.175g of gold reacts with chlorine . The equation for the reaction is 2Au+3Cl2——> 2AuCl2.
Calculate the mass of chlorine needed to react with 0.175g of gold .
Relative atomic mass:
Cl=35.5
Au=197
0
1 year ago
#2
47.3 Mg
1
#3
how did you get that?
0
1 year ago
#4
(Original post by ru6y)
how did you get that?
Moles = mass/mr
Find moles of gold using that formula.
You know the ratio is 2:3 so utilise that ratio
Find the moles of chlorine with that ratio
Then multiply by mr, but remember it’s Cl2, not Cl
1
1 year ago
#5
(Original post by sweetescobar)
47.3 Mg
Don’t you have to include the fact that chlorine is diatomic, therefore multiply by 71 and not 35.5?
0
1 year ago
#6
Oh shoot ya I forgot about that
0
1 year ago
#7
(Original post by UrFellowMedic)
Moles = mass/mr
Find moles of gold using that formula.
You know the ratio is 2:3 so utilise that ratio
Find the moles of chlorine with that ratio
Then multiply by mr, but remember it’s Cl2, not Cl
Exactly.
0
1 year ago
#8
(Original post by UrFellowMedic)
Moles = mass/mr
Find moles of gold using that formula.
You know the ratio is 2:3 so utilise that ratio
Find the moles of chlorine with that ratio
Then multiply by mr, but remember it’s Cl2, not Cl
Correct!
0
1 year ago
#9
The fact that I didn't clock that Cl2 has ruined my day.
0
1 year ago
#10
(Original post by sweetescobar)
The fact that I didn't clock that Cl2 has ruined my day.
It’s all good bro 😂 I remember losing 3 marks on an 8 marker cos I read Na2CO3 as NaCO3, so annoyinggg.
0
#11
thank yall so much
0
1 year ago
#12
(Original post by UrFellowMedic)
Moles = mass/mr
Find moles of gold using that formula.
You know the ratio is 2:3 so utilise that ratio
Find the moles of chlorine with that ratio
Then multiply by mr, but remember it’s Cl2, not Cl
wait what im so confused
0
1 year ago
#13
so would the answer be 94.61mg?
did you convert the mass of gold into mg at the start by a factor of x1000 to get it into mg?
Last edited by aylamayd; 1 year ago
0
1 year ago
#14
(Original post by aylamayd)
so would the answer be 94.61mg?
did you convert the mass of gold into mg at the start by a factor of x1000 to get it into mg?
yh u do do that im pretty sure, thats what i did anyways
0
1 year ago
#15
look here it shows you how to do these calculations

https://www.science-revision.co.uk/m...equations.html
0
1 year ago
#16
Can someone give full working out
0
1 year ago
#17
(Original post by Bdduhd)
Can someone give full working out
I have a step by step foolproof method, try applying it. If you are really really stuck then I can send full working out. But do try it to help you learn.
0
1 year ago
#18
(Original post by UrFellowMedic)
I have a step by step foolproof method, try applying it. If you are really really stuck then I can send full working out. But do try it to help you learn.
0
1 year ago
#19
(Original post by UrFellowMedic)
I have a step by step foolproof method, try applying it. If you are really really stuck then I can send full working out. But do try it to help you learn.
Yes please send full I can then do more examples using the working out to help me
0
1 year ago
#20
(Original post by Bdduhd)
Yes please send full I can then do more examples using the working out to help me
2
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