Balancing Equations?

Question

a) Fe2O3(s) + Mg(s) -> MgO(s) + Fe(s)
b) AlCl3(s) + H2O(L) -> Al(OH)3(s)+ HNO3(g)
c) NaNO3 + H2SO4(L) -> Na2SO4+ HNO3 (g)
d) NiCO3(s) + HNO3(aq) -> Ni(NO3)(aq) + CO2(g) + H2O(l)]

Can someone explain how to balance these equations?

The answer I got from a was...

2 Fe2O3 + 6 Mg = 6 MgO(s) + 4Fe

For B the answer I got is:

2 NaNo3 + H2SO4 -> Na2SO4 + 2 HNO3

Thanks and the top answer was for C.

I'm having probable balancing the equation C6H5CH3 + O2 -> H2O + CO2

Answer 1

All balancing an equation is simply that you're making the sides equal.

Ignore that O is Oxygen, just think of it as a letter, it's much less confusing.

I'll explain the first one, you can do the rest.

How many Fe's do you have on each side?

Two on the left and one the right.

Is this balanced? No.

So what do you do?

Add a 2 before the Fe on the right!

Now how many Fe's are there on each side? Two! They're happy!

How many O's do we have? Three on the left and one on the left.

So add a 3 before the Mg because you can't break MgO up.

Keep thinking like this through out the problem and you should get.

Fe2O3+ 3Mg-----> 3MgO+2Fe.

Answer 2

I'll just give you the numbers.

a. (1), 3, 3, 2
b. You've typed this in wrongly. You might mean Al(OH)3 + 3HNO3 -----> Al(NO3)3 + 3H2O
c. 2, (1), (1), 2
d. (1), 2, Ni(NO3)2, (1), (1)

Where I have put (1), of course, you don't actually put a number.