Balancing Chemical Equations.

  • Thread starter Draggu
  • Start date
102
0
1. The problem statement, all variables and given/known data
1. Li + H2O ->
2. K + H2O ->
3. Na + H2O ->
4. Ca + H2O ->
5. Mg + H2O ->
6. Cs + H2O ->
7. H + At ->
8. Na + At ->


2. Relevant equations



3. The attempt at a solution
1. 2Li + 2H2O -> H2 + 2LiOH
2 & 3: Same for 1.

Others I have no idea how to do. I was NOT taught these and she somehow thinks we were.
 

mgb_phys

Science Advisor
Homework Helper
7,657
11
Do you have a periodic table?
Do you know about groups and valence?
So how many OH each of the metals needs to make a stabel compound.

ps. In your answer, how many H are on the right side of the equation?
 
102
0
Do you have a periodic table?
Do you know about groups and valence?
So how many OH each of the metals needs to make a stabel compound.

ps. In your answer, how many H are on the right side of the equation?
THe main problem is what the new product is. How would I know what Na + At, would create, etc,
 

mgb_phys

Science Advisor
Homework Helper
7,657
11
Lithium is group 1 so it has one outer electron, and so it needs one OH group to plug into.
Sodium/Potassium are also group one, Magnesium and Calcium are group 2 so have 2 outer electrons and can plug into two OH groups
 
102
0
Lithium is group 1 so it has one outer electron, and so it needs one OH group to plug into.
Sodium/Potassium are also group one, Magnesium and Calcium are group 2 so have 2 outer electrons and can plug into two OH groups
I don't really understand. Can you show me examples?
 

mgb_phys

Science Advisor
Homework Helper
7,657
11
I don't really understand. Can you show me examples?
Do you know why it is 2Li + 2H2O -> H2 + 2LiOH ?

Lithium has 1 outer electron available for this sort of chemical reaction.
Oxygen is 2 electrons short.
Hydrogen is a little odd, it can be thought of as having one extra electron or one short - it has a single electron in an orbit that can hold 2.

The OH group has 2 spare slots on the oxygen and one of them filled by the hydrogen, so one free slot overall.
Lithium as we said has one extra electron which fits into this slot, making LiOH.
Magnesium has 2 outer electrons so needs to attach two OH groups = Mg(OH)2

Then it's just a matter of counting how many H2O you need to make everything balance.
 
102
0
Do you know why it is 2Li + 2H2O -> H2 + 2LiOH ?

Lithium has 1 outer electron available for this sort of chemical reaction.
Oxygen is 2 electrons short.
Hydrogen is a little odd, it can be thought of as having one extra electron or one short - it has a single electron in an orbit that can hold 2.

The OH group has 2 spare slots on the oxygen and one of them filled by the hydrogen, so one free slot overall.
Lithium as we said has one extra electron which fits into this slot, making LiOH.
Magnesium has 2 outer electrons so needs to attach two OH groups = Mg(OH)2

Then it's just a matter of counting how many H2O you need to make everything balance.
So then Mg + 2H2O -> H2 + Mg(OH)2
 

mgb_phys

Science Advisor
Homework Helper
7,657
11
Bizarre example, Astatine (if you could get any) is chemically the same as Chlorine - what is the formula for Sodium and Chlorine
 
102
0
Bizarre example, Astatine (if you could get any) is chemically the same as Chlorine - what is the formula for Sodium and Chlorine
So Na + At -> NaAt

At + H - > AtH?
 
1,087
0
Yer, or HAt is normally the order.
 

mgb_phys

Science Advisor
Homework Helper
7,657
11
And you have to balance it so that it's H2 or At2
 

mgb_phys

Science Advisor
Homework Helper
7,657
11
Because that's how it occurs as as molecules on the left side of the equation
 
1,087
0
Does hydrogen travel around in simple atoms? Is it stable in relation to electron valency?

EDIT:
7. H + At ->
It is missing in the original question.

The Bob
 

Want to reply to this thread?

"Balancing Chemical Equations." You must log in or register to reply here.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Top Threads

Top