How to understand chemical reactions as you learn them

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Mvpmb
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#1
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#1
I'm so sick of memorising all this ****ing jibberish is there any way I can actually understand it?

For example

Reactions of carbonyls in a2
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alow
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#2
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#2
The OCP Core Carbonyl Chemistry is good.
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Snuffleq
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#3
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#3
(Original post by alow)
The OCP Core Carbonyl Chemistry is good.
HI, I'm having trouble with constructing equations. Would you be able to explain why the symbol equation for Sodium reacting with Oxygen is = Na+02 -> Na20 ?

Does this have to do with the crossover rule?
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TheConfusedMedic
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#4
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(Original post by Samistrawberry)
HI, I'm having trouble with constructing equations. Would you be able to explain why the symbol equation for Sodium reacting with Oxygen is = Na+02 -> Na20 ?

Does this have to do with the crossover rule?
Na forms the ion: Na+
O forms the ion: O2-

Due to the crossover rule, you need 2 sodium ions to balance out the charges so that the overall charge of the compound is 0.

I believe the equation would be:
4Na + O2 --> 2Na2O ?
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I think
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Snuffleq
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#5
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#5
(Original post by surina16)
Na forms the ion: Na+
O forms the ion: O2-

Due to the crossover rule, you need 2 sodium ions to balance out the charges so that the overall charge of the compound is 0.


I believe the equation would be:
4Na + O2 --> 2Na2O ?
Spoiler:
Show
I think
Ah, so that is why we use the crossover rule. I've forgotten the basics :eek:
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TheConfusedMedic
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#6
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#6
(Original post by Samistrawberry)
Ah, so that is why we use the crossover rule. I've forgotten the basics :eek:
It's gcse C1
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Snuffleq
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#7
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#7
(Original post by surina16)
It's gcse C1
I remember being taught the crossover rule but it was never explained. Thank you!
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TheConfusedMedic
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#8
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#8
(Original post by Samistrawberry)
I remember being taught the crossover rule but it was never explained. Thank you!
No worries!
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I think the reason is so that the ions can have a full outer shell, turning them into atoms, which is why the overall charge is 0
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Snuffleq
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#9
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#9
(Original post by surina16)
No worries!
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I think the reason is so that the ions can have a full outer shell, turning them into atoms, which is why the overall charge is 0
So I guess you only use the cross method when constructing an equation when ions react.
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Butternuts96
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#10
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#10
(Original post by Mvpmb)
I'm so sick of memorising all this ****ing jibberish is there any way I can actually understand it?

For example

Reactions of carbonyls in a2
Group all similar reactions together and understand what's happening in each equation individually and you'll start to notice the pattern. If you can't understand, use your chem teacher, a good textbook, youtube or all three. If you still can't understand, maybe Chemistry's not for you.
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KombatWombat
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#11
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#11
(Original post by surina16)
No worries!
Spoiler:
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I think the reason is so that the ions can have a full outer shell, turning them into atoms, which is why the overall charge is 0
You're right to make sure that they has a full outer shell, but they're ions in Na2O! An oxygen atom has 6 electrons in its outer shell, so the anion is O2- and has 8 (i.e. a full shell). A sodium atom has 1 electron in its outer shell, so its ion is Na+

You need to make sure the charges cancel out so your overall compound is neutral which is why its Na2O
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Snuffleq
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#12
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#12
(Original post by KombatWombat)
You're right to make sure that they has a full outer shell, but they're ions in Na2O! An oxygen atom has 6 electrons in its outer shell, so the anion is O2- and has 8 (i.e. a full shell). A sodium atom has 1 electron in its outer shell, so its ion is Na+

You need to make sure the charges cancel out so your overall compound is neutral which is why its Na2O
If I was to write the formulae for lead phosphate how would I know whether it should be Pb2+ or Pb4+?
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KombatWombat
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#13
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#13
(Original post by Samistrawberry)
If I was to write the formulae for lead phosphate how would I know whether it should be Pb2+ or Pb4+?
It gets complicated that far down the periodic table! The full electron shell rule doesn't work so well. It's Pb2+ but I'd have thought you'd be told that.
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Snuffleq
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#14
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#14
(Original post by KombatWombat)
It gets complicated that far down the periodic table! The full electron shell rule doesn't work so well. It's Pb2+ but I'd have thought you'd be told that.
Ah so it's to do with sub shells. Any reason as to why there is two different versions?
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