Ionic equations help.

Well basically I've started AS and I'm struggling quite a lot. But anyway we got a questions asking us to 'write out an ionic equation for the reaction of magnesium with sulfuric acid'

So I got Mg(2+) + H2(2+)SO4(2-) ----> Mg2SO4 + H2.

Please help me.
Thank you. :smile:

I'm a tad confused and really worried because if I struggle with this, how am I going to fare with other topics?

Anyone?

Original post by senz72

I'm a tad confused and really worried because if I struggle with this, how am I going to fare with other topics?

First of all in an equation make sure the state symbols are in. Then if the same compound, e.g. so4 comes up in both the reactants and the product, then it is a spectator and is NOT meant to be included in your ionic equation.

Give me the original equation and the state symbols then i'll help you :smile:

Reply 3

senz72

Original post by EffKayy

This is the question.

Write out an ionic equation for the reaction of magnesium with sulfuric acid.

Reply 4

EierVonSatan

You're worrying too much and you have to wait more than a few minutes for a reply normally :yep:

Step 1, write the full equation: Mg_(s) + H₂SO_4(aq) ---> MgSO_4(aq) + H_2(g)

step 2, split up the aqueous components into ions: Mg_(s) + 2H⁺_(aq) + SO₄^2-_(aq) ---> Mg²⁺_(aq) + SO₄^2-_(aq) + H_2(g)

step 3: cancel ions that appear on both sides, can you finish that bit? :smile:

(edited 12 years ago)

Reply 5

senz72

Original post by EierVonSatan

You're worrying too much and you have to wait more than a few minutes for a reply normally :yep:

Step 1, write the full equation: Mg_(s) + H₂SO_4(aq) ---> MgSO_4(aq) + H_2(g)

step 2, split up the aqueous components into ions: Mg_(s) + 2H⁺_(aq) + SO^2-_4(aq) ---> Mg²⁺_(aq) + SO^2-_4(aq) + H_2(g)

step 3: cancel ions that appear on both sides, can you finish that bit? :smile:

So Mg + 2H+ --> Mg+ H2?

Sorry about this.

P.S It asks for the full, balanced ionic equation.

(edited 12 years ago)

Reply 6

EierVonSatan

Original post by senz72

So Mg + 2H+ --> Mg+ H2?

Sorry about this.

P.S It asks for the full, balanced ionic equation.

You just need the state symbols and the charge on Mg on the right :yes:

Reply 7

senz72

Original post by EierVonSatan

You just need the state symbols and the charge on Mg on the right :yes:

Thank you.

Could you help me with one or two more problems?

Feel free to say no. :smile:

Reply 8

EierVonSatan

Original post by senz72

Thank you.

Could you help me with one or two more problems?

Feel free to say no. :smile:

Just post your questions and someone will answer them, it's what the forum is for :smile:

Reply 9

Tortious

Original post by EierVonSatan

Just post your questions and someone will answer them, it's what the forum is for :smile:

Hi, I've got a few questions about ionic equations too (hopefully OP doesn't mind me using this thread rather than starting a new one!). I'm not a chemist but my sister's doing AS and she doesn't understand this either.

I'm trying to work through some of her problems and I understand the idea of...erm..."cancelling out" terms like you can in algebra, but I haven't managed to get correct answers yet.

•

Do you only split the aqueous components of the equation into individual terms (with + signs between, I mean)?

•

How is it possible to identify which are aqueous? Is it on the basis of there being $H_2O$ in there?

•

If there are several of a component on one side of the equation and only one on the other, can you "subtract" that one component or not?

To give you an example of the kind of thing I'm working with:

H_2SO_4 + 2NaOH \rightarrow 2H_2O + Na_2SO_4

I've broken down the aqueous components (but I'll omit the charge notation since I'm not sure how it works):

H_2 + SO_4 + 2NaOH \rightarrow 2H_2 + O + Na_2SO_4

There's

1H_2

on the left and

2H_2

on the right - can I subtract

H_2

from both sides? :confused:

(I don't think so but decided I'd better check...)

Thanks so much for your help - this is due tomorrow ( :facepalm2:

) so I'd appreciate any insight! :h:

(edited 12 years ago)

Reply 10

EierVonSatan

Original post by Tortious

Coolio

Answers in bold:

•

Do you only split the aqueous components of the equation into individual terms (with + signs between, I mean)? Yep

•

How is it possible to identify which are aqueous? Is it on the basis of there being $H_2O$ in there? Sometimes it's given, other times it'll be implied

•

How do charges work? Is 2Na the same as $Na_2$ (in that both have a +2 effect)? If so, would you write "2+" for the "power" in both cases? (Sorry for the Maths analogies - it's the only thing like this I'm really familiar with :colondollar: ) Nope, 2Na means (2 x Na) while Na₂ is more like ''Na²'' if the algebra analogy helps :p: i.e. 2Na is two sodium atoms while Na₂ is two sodium atoms attached to each other in a molecule...

•

If there are several of a component on one side of the equation and only one on the other, can you "subtract" that one component or not? Yes such as 2A + B ----> C + A becomes A + B ---> C

To give you an example of the kind of thing I'm working with:

I've broken down the aqueous components (but I'll omit the charge notation since I'm not sure how it works):

H_2 + SO_4 + 2NaOH \rightarrow 2H_2 + O + Na_2SO_4

The charges are all important as it describes the way the molecules are built it should be:

2H⁺ + SO₄^2- + 2Na⁺ + 2OH^- ---> 2H₂O + 2Na⁺ + SO₄^2-

Importantly water is not an ionic compound and should not be split up into ions...

There's

1H_2

on the left and

2H_2

on the right - can I subtract

H_2

from both sides? :confused:

Thanks so much for your help - this is due tomorrow ( :facepalm2:

) so I'd appreciate any insight! :h:

Can you now see the equivalent ''terms'' on both sides? :smile:

(edited 12 years ago)

Reply 11

Tortious

Original post by EierVonSatan

The charges are all important as it describes the way the molecules are built it should be:

2H⁺ + SO₄^2- + 2Na⁺ + OH^- ---> 2H₂O + 2Na⁺ + SO₄^2-

Importantly water is not an ionic compound and should not be split up into ions...

Cheers - answering my initial questions has certainly helped to make things clearer. However, I'm not following your last few steps.

Are the charges supposed to cancel out (on each side of the equation)? From the little Chem I do remember, I know H and Na are in Group 1, so I'd have thought that 2H⁺ represents 2 "lots of" positive charge. As such, adding the charges, I'd get (+2) + (-2) + (+2) + (-1) = +1. Or do you not "multiply" the charge by the coefficient to take into account the magnitude?

Thanks again. :hugs:

Reply 12

EierVonSatan

Original post by Tortious

Yeah, I think this is the point where the chemistry kicks in and the algebra analogy won't help you. It's probably been a while since you did GCSE science so...

On both sides of a chemical equation two things need to be equal: the mass and the charge - thus you can't have more charge on one side than the other.

There are two main compound types - covalent species and ionic ones, the former will not split up into ions when dissolved (water is such an example). The latter will as they're made up from ions (atoms with charges) such as NaCl.

Undissolved NaCl is an ionic solid, add some water and it splits up into it's two sets of ions Na⁺ and Cl^-, these ions are formed because they lose/gain electrons to fill their outermost shell (i.e. to be more stable). This can be written: NaCl ---> Na⁺ + Cl^- (mass and charge balanced).

2H⁺ means 2 x H⁺ = total charge of +2

for the example: 2H⁺ (+2) + SO₄^2- (-2) + 2Na⁺ (+2) + 2OH^- (-2) ---> 2H₂O + 2Na⁺ (+2) + SO₄^2- (-2)

0 = 0 i.e. overall neutral, as we'd expect a full equation to be

p.s. sorry, I missed the 2 in front of the OH^- above :colondollar:

Reply 13

Chloeisabelle_

I need to know the ionic equation for sulfuric acid... anyone help? :smile:

Reply 14

Pigster

Original post by Chloeisabelle_

I need to know the ionic equation for sulfuric acid... anyone help? :smile:

Rather than find a six year old thread, just start one of your own.

Sulfuric acid doesn't have an "ionic equation": it has a formula. It is made of ions and (some of) these can be shown in an ionic equation, when it reacts with something else.

What are you reacting it with?

(edited 3 years ago)

Reply 15

bopppppp

I don't have a clue lol I got the same question

Reply 16

ishie889

Original post by senz72

I'm a tad confused and really worried because if I struggle with this, how am I going to fare with other topics?

you probably won't see this but i have started year 12 this september and i'm pretty i've got given the exact same sheet as you did 9 years ago - i just think it's funny how i literally have the same problem as you did because i don't get it all LMAO

Reply 17

Pigster

Original post by ishie889

I can't believe that I have just corrected a spelling mistake that I made three years ago telling someone not to resurrect a thread from (then) six years ago.

I'll bet that it won't be the same worksheet. That equation is a fairly standard example as an introduction to ionic equations.