Balancing Equations

Here are a ton of problems for balancing equations: I challenge you to time yourself and post the time it takes to complete them.  But first, some tips:

Use the REP method. REP stands for Reactants, Element, Product. It's simple and a handy little chart that helps you keep track of the reactants and products, of course.  Here's a sample diagram to balance N2 + H2 -> NH3

R: 2  2

E: N H

P: 1  3

Does it start to make sense? You make the E row first, as it is all the elements that appear in the equation.  Then, just write the amounts of reactants/products above and below its corresponding element.  If I balance the equation like so: N2 + 3H2 -> 2NH3 then I will have to change my REP table

R: 2  6

E: N H

P: 2  6

See how the R and P columns match? Once they match, then you are done.  If they don't, then just keep on fiddling with those coefficients.

So, one of my old worksheets on balancing equations, in a nutshell:

KClO3 -> KCl + O2

NaCl+ F2 -> NaF + Cl2

H2 + O2 -> H2O

Pb(OH)2 + HCl -> HO4 

AlBr3 + K2SO4 -> KBr + Al2(SO4)3

CH4+ O2 -> CO2 + H2O

C3H8 + O2 -> CO2 + H2O

C8H18 + O2-> CO2 + H2O

FeCl3 + NaOH -> Fe(OH)3 + NaCl

P + O2 -> P2O5

Na + H2O -> NaOH + H2

Ag2O -> Ag + O2

S8 +O2 -> SO3

CO2 + H2O -> C6H12O6 + O2

K + MgBr -> KBr + Mg

HCl + CaCO3 -> CaCl2 + H2O + CO2

H2O + O2 -> H2O2

NaBr + CaF2 -> NaF + CaBr2

H2SO4 + NaNO2 -> HNO2 + Na2SO4