[jennielynn_1980]

I have to write and balance equations for some reactions but I don't know how to figure out which reaction to use for each (is it reduction, oxidation, etc.).  Is there a rule for figuring this out?  I read the chemtutor notes and it explains each type but it assumes you know both the side of the equation which I don't have.

One question looks like this (I have to write the reaction and balance it):

calcium + water ------>

So I guess the first step is

Ca + H₂O ------>

what would be the next step?

[mike]

These are the types of reactions that you will have to memorise the general rules. Generally metals will react with water to form metal hydroxide or metal oxides. This may happen at room temperature, bioling or maybe steam depending on the reactivity of the particular metal in question. One of the products of these reactions is usually always hydrogen gas (H₂).

Ca + H₂O ---->

Ca + H₂O ----> Ca(OH)₂ + H₂

balance:

Ca + 2H₂O ----> Ca(OH)₂ + H₂

Some other "general reaction rules" include:

acid + base = salt + water

metal + acid = salt + H₂

redox reactions and displacement reactions = you will probably have to study reduction potentials and reactivity series' for these (I am not sure where you are up to with this type of thing)

[jennielynn_1980]

Thanks for your help

I don't know where I am supposed to be either.  I am not in highschool but I am taking 12th grade advanced chemistry through homestudy so I don't know what I am already expected to know.  It seems all over the place though.  They expect you to know reactions and then explain it all later.  I don't really see the reasoning they use in the order of things being taught which is partially why I am so confused and always asking silly questions around here 

[jennielynn_1980]

Okay, so I looked some things up and I found info on:

replacement reactions
double replacement reactions
synthesis
decomposition
neturalization
combustion
Acid oxides
basic oxides

I understand the basics of these like A + B ----> AB etc., but I still am struggling with more complicated reactions like

gold (III) sulfate + barium cholride -----> ??

so gold sulfate is a salt right?  Then barium cholride is what?  Is it a base so this is a neturalization reaction?

[Albert]

Barium chloride is a salt. The reaction you propose may be an oxidoreduction.

[Borek]

Barium chloride is a salt. The reaction you propose may be an oxidoreduction.

No. Think about solubilities. What will happen when you mix sulfate with barium chloride?

[constant thinker]

Barium chloride (BaCl₂) is a salt. Remember a salt is an ionic compound.

[Edit] Albert and Borek both beat me to this.

[Albert]

Yes, Borek is right as usual: however, I just pointed out BaCl2 is a salt and I wanted to say that reactions involving salts can sometimes be oxidoreductions.

[jennielynn_1980]

geez, I have so much to learn!

Okay, so if I were to do this problem ---^ of gold (III) sulfate + barium chloride I have to know what to start the process of solving this problem?

1. I have to figure out the chemical formula for each compound
2. then I have to figure out what they are (what are my options here? acid, oxyacid, salt, base, acid salt, peroxide and what else am I missing here?)
3. figure out how they react together (so if acid and base they neutralize for example)
4. finally balance the equation

Would these be reasonable steps?  What am I missing?

[Albert]

Looks like a reasonable pathway.

[Bel-p]

gold (III) sulfate + barium chloride -->

So what is the answer to this one in the end?
The gold won't react with anything will it, as it doesn't react at all/easily?
So would you get barium sulfate + chlorine and gold?
Or what?

[Dan]

The gold won't react with anything will it, as it doesn't react at all/easily?

Careful now! Gold (III) is not the same as gold. Gold is indeed relatively unreactive, but gold (III) is a powerful oxidising agent - but it won't oxidise Ba²⁺

As has been said, think about solubility...