balancing chemical equations! help plz!?

Question

these are the only ones i couldn't do. help would be nice. please and thank you! (O and all the #'s are the subscripts)

H2O2 ==> H2O + O2

Na + H20 ==> NaOH + H2

C2H6 + O ==> CO2 + H2O

Mg(NO3)2 + K3PO4 ==> Mg3(PO4)2 + KNO3

Answer 1

2H2O2 -->2H2O + O2

2Na + 2H2O -->2NaOH + H2

2C2H6 + 7O2 --> 4CO2 + 6H2O

3Mg(NO3)2 + 2K3PO4 --> Mg3(PO4)2 + 6KNO3

You will learn nothing by copying these answers. You should try to balance each equation without looking at the answers. If you learn how the balance the equations, you might be able to balance the equations on your test.

I'll explain the steps I followed on one equation-

C2H6 + O2 --> CO2 + H2O
I have 2C and 6H on the left side so I need 2CO2 and 3H2O on the right side
C2H6 + O2 --> 2CO2 + 3H2O
Now I have 2 O on the left side and 7 O on the right side
I need 5 more O on the left side (2.5 O2)
C2H6 + 3.5O2 --> 2CO2 + 3H2O
Usually formula coefficients are written as whole numbers. I'll multiply all coefficients by 2 to get whole number coefficients.
2C2H6 + 7O2 --> 4CO2 +6H2O

Answer 2

2H2O2 ===> 2H2O + O2

2Na + H2O ===> 2NaOH + H2

2C2H6 + 7O2 ===> 4CO2 +6H2O

3Mg(NO3)2 + 2K3PO4 ===> Mg3(PO4)2 + 6KNO3