Need help on how to balance equations. Here are a few of the problems.

First let me supply the w/s directions:

Predict the products of the reactions below. Then, write the balanced equation and clasify the reactions.

Here are examples of a few of the different kinds of equations I have to balance:

1. sodium + hydrogen

2. sulfuric acid + sodium hydroxide

3. hydrogen peroxide

4. zinc + hydrochloric acid

I really don't understand how any of this is done, so, an explaination of where any numbers or such comes from would be ideal.

1 answer

In order to avoid memorizing thousands of equations, one tries to categorize equations into groups or types. You have several types here. I won't balance all of them or give products but I think I can get you started.
First look at the activity series in your text or on the internet. Here is a good one on the net.
http://en.wikipedia.org/wiki/Reactivity_series
Look where Na is on the series. Very high. That means high reactivity.
Na + H2 ==> NaH but I don't know if this reaction will go at room temperature or not.
H2SO4 + NaOH ==> acid + base gives a salt + water. A good type to remember.
H2O2 ==> a decomposition reaction. Forms O2 and H2O.
Zn + HCl ==> If the metal is ABOVE H in the activity series, then H2 gas + the salt is produced. If the metal is BELOW H in the activity series, there is no reaction. Another good type to remember.