chemistry help

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 .
Give your answer in Mg
Relative atomic mass:
Cl=35.5
Au=197

47.3 Mg

how did you get that?

Reply 3

UrFellowMedic

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

Reply 4

UrFellowMedic

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?

Reply 5

sweetescobar

Oh shoot ya I forgot about that :colonhash:

Reply 6

sweetescobar

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.

Reply 7

Bmal

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!

Reply 8

sweetescobar

The fact that I didn't clock that Cl2 has ruined my day.

Reply 9

UrFellowMedic

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.

Reply 10

ru6y

thank yall so much :smile:

Reply 11

sddssss

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

Reply 12

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?

(edited 2 years ago)

Reply 13

sddssss

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

Reply 14

scimus63

look here it shows you how to do these calculations

https://www.science-revision.co.uk/moles%20and%20equations.html

Reply 15

Bdduhd

Can someone give full working out

Reply 16

UrFellowMedic

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.

Reply 17

Bdduhd

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 it

Reply 18

Bdduhd

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.