Balancing Equations Can We Do It? Yes We can!!!

Make your molecules with marshmallows H2 + O2  H2O +  H O Make your molecules with marshmallows and toothpicks. Now take an inventory: H ___ O ___ 2 H ___ O ___ 2 2 1 Balanced? Nope, now what?

+  H O The molecules themselves cannot be changed but there must be the same number of each type of atom on each side of the yields sign in order to be balanced. When adding a coefficient to the equation, it will multiply the number of each type of atom in that formula.

H2 + O2  H2O 2 +  Now we have: H ___ O ___ 2 H ___ O ___ 4 Still not balanced! 2 2

2 H2 + O2  H2O 2 TaDa!! +  Now we have: H ___ O ___ 4 H ___ O ___ 4

Na + MgCl2  NaCl + Mg +  Na ___ Mg ___ Cl ___ 1 Na ___ Mg ___ Cl ___ Not balanced

Na + MgCl2  NaCl + Mg 2 Na Cl Mg Cl Na + Mg +  Na Cl With 2 Cl’s on the reactant side, we want to make 2 Cl’s on the products side… Na ___ Mg ___ Cl ___ 1 Na ___ Mg ___ Cl ___ 2 Not balanced yet… Now we have: 1 1 2 2

2 Na + MgCl2  2 NaCl + Mg Na Cl Mg Cl Na + Mg +  Na Cl Na Now we need to even up our sodiums (Na’s) Na ___ Mg ___ Cl ___ 2 Na ___ Mg ___ Cl ___ 2 Take inventory: Yippee!! 1 1 2 2

CH4 + O2  CO2 + H2O  C ___ H ___ O ___ C ___ H ___ O ___ Not 1 1 Not balanced 4 2 2 3

CH4 + O2  CO2 + H2O 2  C ___ C ___ H ___ H ___ O ___ O ___ Nope, 1 C ___ H ___ O ___ 1 4 Nope, not yet… 4 2 4

CH4 + O2  CO2 + H2O 2 2 WooHoo!!  C ___ C ___ H ___ H ___ O ___ 1 C ___ H ___ O ___ 1 4 4 WooHoo!! 4 4

Now let’s try some without the marshmallows….. Al2O3 + H2  H2O + Al 3 3 2 Don’t forget to box off your formulas so you don’t mess with them! Inventory: We did it!! Al ___ O ___ H ___ 2 Al ___ O ___ H ___ 1 2 3 1 3 6 2 6 2

Fe + O2  Fe2O3 4 3 2 I think we’ve got it!! Fe ___ O ___ 1 4 Fe ___ 6 3 6 This one’s tricky—start with oxygen and use the lowest common denominator.

The End!