Download Zn + HCl → ZnCl 2 + H2 NaOH + H3PO4 → Na3PO4 + H2O N2 +

Strategy for Balancing Chemical Equations
1) Write all the reactant and product formulas on the left and right side of the equation,
respectively. Make sure you have all and that you have written the formulas correctly.
„ Now, never touch the subscripts in the formulas again.
„ Different subscripts = different molecules
2) Balance the equation by trying different coefficients to make the number of atoms of
each element the same on both sides of the equation. Remember to multiply by the
subscript when adding up numbers of atoms (eg, 3H2O has 6 H atoms). Only change the
coefficients (numbers in front of the formula), never the subscripts.
„ This is a trial-and-error process, so work in pencil and be patient with
yourself!
„ Look at only one type of atom at a time.
„ Start with atoms that appear only once on each side of the equation.
„ Once those are balanced, try to balance atoms that appear in more than one
species on either side of the reaction.
„ Tip: If there is a molecule with only one type of atom (eg, O2), sometimes it
helps to save that type of atom for last.
3) Check to make sure coefficients are as small as possible (all whole numbers). If your
coefficients are 2, 2, 4, and 2, for example, reduce them to 1, 1, 2, and 1.
4) Check your balanced equation, one type of atom at a time, to make sure it is fully
balanced.
Zn +
NaOH +
HCl Æ
H3PO4 Æ
N2 +
C2H6 +
ZnCl2 +
H2
Na3PO4 + H2O
H2 Æ NH3
O2 Æ
CO2 +
H2O