How do you balance tricky chemical equations

Watch this thread
val7322
Badges: 14
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 4 months ago
#1
can someone tell me their process to solve thisName:  Screenshot 2022-01-08 2.51.50 PM.png
Views: 30
Size:  22.3 KB
Last edited by val7322; 4 months ago
0
reply
TriplexA
Badges: 18
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 4 months ago
#2
(Original post by val7322)
can someone tell me their process to solve thisName:  Screenshot 2022-01-08 2.51.50 PM.png
Views: 30
Size:  22.3 KB
Hi there.

First balance the C's so there's the same number on each side.
Then balance O.
Then balance H.

If you could show me your final equation just as a final check - that'd be great
Last edited by TriplexA; 4 months ago
0
reply
username5613084
Badges: 19
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 4 months ago
#3
(Original post by val7322)
can someone tell me their process to solve thisName:  Screenshot 2022-01-08 2.51.50 PM.png
Views: 30
Size:  22.3 KB
You will need an old style weighing scale
2
reply
ghostwalker
Badges: 17
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 4 months ago
#4
(Original post by val7322)
can someone tell me their process to solve thisName:  Screenshot 2022-01-08 2.51.50 PM.png
Views: 30
Size:  22.3 KB
Prehaps not the simplest, but:

Start by assuming 1 molecule of glucose, becomes a,b,c molecules of propanone, carbon dioxide, and water respectively.

Then consider the no. of C atoms. On the left we have 6, and on the right 3a+b. Giving us one equation:

6=3a+b.

Repeat for H and O.

Solve the 3 simultaneous equations, to get an initial chemical equation.

Your values for a,b,c may be, and in this case are, fractions, so multiply through by the lowest common multiple of the denominators of any fractions to get your desired result.
Last edited by ghostwalker; 4 months ago
2
reply
val7322
Badges: 14
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 4 months ago
#5
(Original post by ghostwalker)
Prehaps not the simplest, but:

Start by assuming 1 molecule of glucose, becomes a,b,c molecules of propanone, carbon dioxide, and water respectively.

Then consider the no. of C atoms. On the left we have 6, and on the right 3a+b. Giving us one equation:

6=3a+b.

Repeat for H and O.

Solve the 3 simultaneous equations, to get an initial chemical equation.

Your values for a,b,c may be, and in this case are, fractions, so multiply through by the lowest common multiple of the denominators of any fractions to get your desired result.
I've gotten
6= 3a +b
12 = 6a +2c
6 = a +2b +c

but i dont know how to solve three simultaneous equations
0
reply
ran-dumb
Badges: 19
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 4 months ago
#6
I think it's easier to think this way, the carbon compound on the right has 3 carbons, so looking at the left we have 6 carbons, so its either 1 or 2 of the CH3COCH3. Not that much work to try both, one of them doesn't work and will tell you what to put for the rest.
0
reply
KA_P
Badges: 19
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 4 months ago
#7
(Original post by val7322)
I've gotten
6= 3a +b
12 = 6a +2c
6 = a +2b +c

but i dont know how to solve three simultaneous equations
First you want a
From first equation we have
b = 6 - 3a. (i)
From the second equation we have
c = 6 - 3a. (ii)
Sub this into the third equation to get
6 = a + 2(6-3a) + (6 - 3a)
6 = a + 12 - 6a + 6 - 3a
-12 = - 8 a
12/8 = a
Lol are these supposed to be integers?
Well must've made a mistake but you get the overall method right?
Then you sub the value of a into (i) then (ii) to find the values of b and c
0
reply
ghostwalker
Badges: 17
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report 4 months ago
#8
(Original post by KA_P)
Lol are these supposed to be integers?
Well must've made a mistake but you get the overall method right?
Read my previous post - in full.

val7322 If you're not familiar with solving 3 simulaneous equations, then you can't use this method, though the poster above has given one way to do it. Can't see another easy method, given the oddity of this particular chemical decomposition. Perhaps you can make use of the other posters' suggestions.
Last edited by ghostwalker; 4 months ago
0
reply
KA_P
Badges: 19
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 4 months ago
#9
Ngl what I got taught to do is to make columns with the number of each element present in that molecule. And then trial by fire.

So here goes:
(1) is C6H12O6

(2) is CH3COCH3
(3) is CO2
(4) is H2O
So the total number of each element on each side should be equal therefore: (1) = (2) + (3) + (4)

(1) - C=6 ; H=12 ; O=6

(2) - C=3 ; H=6 ; O=1
(3) - C=1 ; O=2
(4) - H=2 ; O=1
I'm going to multiply (1) by 2.
So (1) - C=12 ; H=24 ; O=12
(2)+(3) [carbon] is 4 carbons. And 12/4 is 3. So let's say that (2) and (3) are potentially each multiplied by 3.
That would mean we have 18 Hydrogens in (2) now but we need 24. 24 - 18 is 6. There's 2 Hydrogens in (4) so (4) must also be multiplied by 3?
So a potential balanced equation could be:
2(1) -> 3(2) + 3(3) + 3(4)
:dontknow:
Last edited by KA_P; 4 months ago
0
reply
Slx.24
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.
#10
Report 4 months ago
#10
(Original post by KA_P)
First you want a
From first equation we have
b = 6 - 3a. (i)
From the second equation we have
c = 6 - 3a. (ii)
Sub this into the third equation to get
6 = a + 2(6-3a) + (6 - 3a)
6 = a + 12 - 6a + 6 - 3a
-12 = - 8 a
12/8 = a
Lol are these supposed to be integers?
Well must've made a mistake but you get the overall method right?
Then you sub the value of a into (i) then (ii) to find the values of b and c
(Original post by KA_P)
Ngl what I got taught to do is to make columns with the number of each element present in that molecule. And then trial by fire.

So here goes:
(1) is C6H12O6

(2) is CH3COCH3
(3) is CO2
(4) is H2O
So the total number of each element on each side should be equal therefore: (1) = (2) + (3) + (4)

(1) - C=6 ; H=12 ; O=6

(2) - C=3 ; H=6 ; O=1
(3) - C=1 ; O=2
(4) - H=2 ; O=1
I'm going to multiply (1) by 2.
So (1) - C=12 ; H=24 ; O=12
(2)+(3) [carbon] is 4 carbons. And 12/4 is 3. So let's say that (2) and (3) are potentially each multiplied by 3.
That would mean we have 18 Hydrogens in (2) now but we need 24. 24 - 18 is 6. There's 2 Hydrogens in (4) so (4) must also be multiplied by 3?
So a potential balances equation could be:
2(1) -> 3(2) + 3(3) + 3(4)
:dontknow:
Wtf ur a mad brainiac too Can I fall harder?
0
reply
KA_P
Badges: 19
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 4 months ago
#11
(Original post by Slx.24)
Wtf ur a mad brainiac too Can I fall harder?
:blushing: it'll be more difficult to catch you 🥺
Spoiler:
Show
Spoiler:
Show
Spoiler:
Show
it's been way too long since I did chem/maths so it could be wrong 🙈


0
reply
Slx.24
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 4 months ago
#12
(Original post by KA_P)
:blushing: it'll be more difficult to catch you 🥺
Spoiler:
Show
Spoiler:
Show
Spoiler:
Show
it's been way too long since I did chem/maths so it could be wrong 🙈


Ur right about that
Tbf, I weigh a feather so might not be that hard

Spoiler:
Show
I didn't even bother reading that shi I just saw the essay of maths and was like "Wao"
0
reply
KA_P
Badges: 19
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 4 months ago
#13
(Original post by Slx.24)
Ur right about that
Tbf, I weigh a feather so might not be that hard

Spoiler:
Show
I didn't even bother reading that shi I just saw the essay of maths and was like "Wao"
😂😂 I'll go to all lengths to catch you dw


Spoiler:
Show
My brain feels like a hackers computer sometimes - even I don't understand how it works
Last edited by KA_P; 4 months ago
0
reply
Slx.24
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.
#14
Report 4 months ago
#14
(Original post by KA_P)
😂😂 I'll go to all lengths to catch you dw


Spoiler:
Show
My brain feels like a hackers computer sometimes - even I don't understand how it works
Hahahaha you better get rdy cus I'm comingggg

Spoiler:
Show
Me who does coding

I'm in your head dun dun dunn
0
reply
KA_P
Badges: 19
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 4 months ago
#15
(Original post by Slx.24)
Hahahaha you better get rdy cus I'm comingggg

Spoiler:
Show
Me who does coding

I'm in your head dun dun dunn
Slxxxxxx 🙈 :rofl: - let's leave this thread railed shall we

Spoiler:
Show
see just for you
0
reply
Slx.24
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.
#16
Report 4 months ago
#16
(Original post by KA_P)
Slxxxxxx 🙈 :rofl: - let's leave this thread railed shall we

Spoiler:
Show
see just for you
Damn it I nearly did it again :rofl: why do I do this everytime :cry:

Spoiler:
Show
Pfft 🦋🦋
0
reply
username5794123
Badges: 19
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 4 months ago
#17
Why would you guys derail this thread? It’s just a guy asking help on a chem question. :afraid:

Also, I condone everything that’s in post #3.
0
reply
KA_P
Badges: 19
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 4 months ago
#18
(Original post by 0ptics)
Why would you guys derail this thread? It’s just a guy asking help on a chem question. :afraid:

Also, I condone everything that’s in post #3.
Twas unintentional :cry:
0
reply
Slx.24
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 4 months ago
#19
(Original post by 0ptics)
Why would you guys derail this thread? It’s just a guy asking help on a chem question. :afraid:

Also, I condone everything that’s in post #3.
Frr 😂 Sleeps da best
0
reply
val7322
Badges: 14
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 4 months ago
#20
(Original post by ghostwalker)
Read my previous post - in full.

val7322 If you're not familiar with solving 3 simulaneous equations, then you can't use this method, though the poster above has given one way to do it. Can't see another easy method, given the oddity of this particular chemical decomposition. Perhaps you can make use of the other posters' suggestions.
I've done it !!!!!!!!
6= 3a +b
12 = 6a +2c
6 = a +2b +c


b = 6-3a
c=6-3a

a+ 2(6-3a) + 6-3a = 6

then

-8a +18 =6
then
8a =12
a= 12/8 = 3/2

subsitute it in b and c, which both equal 3/2

multiply everything by 2 so it would be

2C6H12O6 = 3CH3COCH3 + 3CO2 + 3H2O
0
reply
X

Quick Reply

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

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

How did your AQA Combined Science - Biology Paper 1 go?

Loved the paper - Feeling positive (26)
38.24%
The paper was reasonable (22)
32.35%
Not feeling great about that exam... (13)
19.12%
It was TERRIBLE (7)
10.29%

Watched Threads

View All