Redox Reactions

Oct 2013
4
0
I need help complete reactions. I do not know how to fill in the right side of the reaction.

Ex. 2Mg + Osubscript 2 arrow ??????????
 

Unknown008

CHF Hall of Fame
May 2010
1,658
37
Mauritius
What happens when Mg (Magnesium) reacts with Oxygen (burns)? What are the products?
 
Oct 2013
4
0
I think H becomes a gas (H2) and Mg now has an oxidation # of 2+. I only think that after talking to lab instructor about other reactions. How do you know what happens if it is just a written reaction and not something you see happen?

Thank you!!!
 

Unknown008

CHF Hall of Fame
May 2010
1,658
37
Mauritius
Um, well, there's not hydrogen gas mentioned in the reaction. And I know because I saw it happen once (well more than once :))

How to know it? There are specific trends in reactions and you can often identify them once you get to know that trend. For example, metals react with oxygen will produce a metal oxide, unless they are not reactive enough.

Also, that's correct: Mg now has an oxidation # of 2+. You just need to know what is the compound which is the result of the reaction.
 
Oct 2013
4
0
Ok, so if it is oxide, does that make it O with a 1- oxidation number? I read our book and don't remember any rules for reactions.
 

Unknown008

CHF Hall of Fame
May 2010
1,658
37
Mauritius
Hmm, do you know the position of Oxygen in the periodic table? I would advise that you start using the periodic table :)

Find the group in which Oxygen is in. Usually, elements in group VI (6) have a valency of 2, thus they usually get 2- oxides.

For group VII they usually get 1- oxides.

For group V, they usually get 3- or 5- oxides.

For group IV, they usually get 4- oxides.

For group III, they usually get 3+ oxides.

For group II, they usually get 2+ oxides.

For group I, they usually get 1+ oxides.