Help me with chemistry

Watch this thread
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 2 years ago
#1
https://share.icloud.com/photos/0mw-...wwp0-xLU3SUphw

Can anyone help me with my a level chemistry task that I’ve been set. It’s about spectroscopy and identifying the compounds. You’ll need something to identify the values on the graph.
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 2 years ago
#2
(Original post by Meganbw23)
https://share.icloud.com/photos/0mw-...wwp0-xLU3SUphw

Can anyone help me with my a level chemistry task that I’ve been set. It’s about spectroscopy and identifying the compounds. You’ll need something to identify the values on the graph.
You must be able to work out the empirical formula.

There is a broad peak at about 3300 and a massive peak at about 1700. They should be a massive clue. If the pH less than 7 wasn't enough of a clue for you.

The mass of Br2 gives you the number of mol. The 1:1 ratio with Br2 tells you there is one C=C and therefore how many mol of compound A there is and using the mass, you can work out its Mr, which together with the empirical formula tells you the molecular formula and by now what it could be.

By the way, what does the 'b' stand for?
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report Thread starter 2 years ago
#3
(Original post by Pigster)
You must be able to work out the empirical formula.

There is a broad peak at about 3300 and a massive peak at about 1700. They should be a massive clue. If the pH less than 7 wasn't enough of a clue for you.

The mass of Br2 gives you the number of mol. The 1:1 ratio with Br2 tells you there is one C=C and therefore how many mol of compound A there is and using the mass, you can work out its Mr, which together with the empirical formula tells you the molecular formula and by now what it could be.

By the way, what does the 'b' stand for?
I don’t know what ‘ b’ you’re on about.

How do I work out the mr from the empirical formula
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 2 years ago
#4
(Original post by Meganbw23)
I don’t know what ‘ b’ you’re on about.

How do I work out the mr from the empirical formula
The b in your username.

You can work out the Mr since you know the amount of compound A that you have and the mass of A.
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
Report Thread starter 2 years ago
#5
(Original post by Pigster)
The b in your username.

You can work out the Mr since you know the amount of compound A that you have and the mass of A.
Oh, Brooke
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report Thread starter 2 years ago
#6
I literally cannot think right now and I can’t remember how to work out the mr from empirical formula. I don’t understand how to do it.
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Report 2 years ago
#7
(Original post by Meganbw23)
I literally cannot think right now and I can’t remember how to work out the mr from empirical formula. I don’t understand how to do it.
You can't work out Mr from emp. form.

You can work out how many mol of Br2 reacts and you're told that it reacts with A in a 1:1 reaction, so now you know how many mol of A you have and you're told the mass that that many mol of A has, so you can use n=m/Mr.
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report Thread starter 2 years ago
#8
(Original post by Pigster)
You can't work out Mr from emp. form.

You can work out how many mol of Br2 reacts and you're told that it reacts with A in a 1:1 reaction, so now you know how many mol of A you have and you're told the mass that that many mol of A has, so you can use n=m/Mr.
So the empirical formula is C2H3O Would I divide 2.00 by 43.03 which is the formula of the empirical formula
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#9
Report 2 years ago
#9
(Original post by Meganbw23)
So the empirical formula is C2H3O Would I divide 2.00 by 43.03 which is the formula of the empirical formula
You don't have 43.03 mol of Br2.
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#10
Report Thread starter 2 years ago
#10
(Original post by Pigster)
You don't have 43.03 mol of Br2.
No I know. That value is if you take the the empirical formula and work out the total of the values for each carbon hydrogen and oxygen and add them together.
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#11
Report Thread starter 2 years ago
#11
Do you know what the mr is from the data provided? If you could tell me that would be a great starting point for me so that I could actually answer the question.
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#12
Report 2 years ago
#12
(Original post by Meganbw23)
Do you know what the mr is from the data provided? If you could tell me that would be a great starting point for me so that I could actually answer the question.
How many mol of Br2 are there?
How many mol of A do they react with?
Given that you have 2.00 g of A, what must its Mr be? (n=m/Mr)
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#13
Report Thread starter 2 years ago
#13
(Original post by Pigster)
How many mol of Br2 are there?
How many mol of A do they react with?
Given that you have 2.00 g of A, what must its Mr be? (n=m/Mr)
I don’t know how many moles of br2 there are lol
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#14
Report Thread starter 2 years ago
#14
(Original post by Meganbw23)
I don’t know how many moles of br2 there are lol
0.02 moles of br2 so it would be the same for confound A?
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#15
Report 2 years ago
#15
(Original post by Meganbw23)
0.02 moles of br2 so it would be the same for confound A?
2.00/159.8 isn't quite 0.02, but the real value would also be the amount of A.
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#16
Report Thread starter 2 years ago
#16
(Original post by Pigster)
2.00/159.8 isn't quite 0.02, but the real value would also be the amount of A.
I know it’s like 0.023 something what would I do next to get the mr of A
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#17
Report 2 years ago
#17
(Original post by Meganbw23)
I know it’s like 0.023 something what would I do next to get the mr of A
As I have said already, use n=m/Mr
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#18
Report Thread starter 2 years ago
#18
(Original post by Pigster)
As I have said already, use n=m/Mr
Do I rearrange the equation? What values do I use
0
reply
Pigster
Badges: 20
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#19
Report 2 years ago
#19
(Original post by Meganbw23)
Do I rearrange the equation? What values do I use
n = amount
m = mass
Mr = relative molecular mass

You're going to have to do some of the work. I am not here to just do everything for you.
0
reply
Meganbw23
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#20
Report Thread starter 2 years ago
#20
(Original post by Pigster)
n = amount
m = mass
Mr = relative molecular mass

You're going to have to do some of the work. I am not here to just do everything for you.
I just asked what values I use and if I rearrange the equation ??
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest

How are you feeling about your results?

They're better than I expected (57)
40.43%
They're exactly what I expected (34)
24.11%
They're lower than I expected (50)
35.46%

Watched Threads

View All