Balancing Equations

Balancing Equations Recall: Law of Conservation of Matter: Matter can not be created nor destroyed Matter can only be rearranged Ex: The burning of aluminum to produce aluminum oxide Ex: Al + O2  Al2O3 ?? Where did the extra Al & O come from?? We must balance the equation

The numbers in equations SUBSCRIPTS- These numbers tell you how many atoms of each element are in the compound. *********** You CAN NOT change the subscripts in a formula!!!!! COEFFICIENTS- The BIG numbers in front of the chemical formula. These numbers represent the number of compounds in a reaction. ************ You CAN change the coefficient in a formula!!!! Ex: 4 H2O = = 4 water molecules = 8 Hydrogen & 4 Oxygen Atoms (=Coefficent x subscript)

Steps for Balancing Equations Count the # of atoms on each side of rxn a) Make a list of each type of atom for both sides, keep the order the same!!! If you have polyatomic ions on both side of the rxn treat them as one unit Balance the equation by changing ONLY the coefficients √ your math to see if all elements/ polyatomics are balanced √ to see if the coefficients can be reduced

Ex: 1 (Type?______________) ___Al + ____O2  ____Al2O3

Ex: 2 (Type?______________) ____ C3H8 + ____ O2  ____CO2 + ____H20

Ex: 3 (Type?______________) __ (NH4)3PO4 + __ Pb(NO3)4  __ Pb3(PO4)4 + __ NH4NO3

Ex: 4 (Type?______________) ____ Al + ____ Fe2N2  ____ AlN + ____Fe

Ex: 5 (Type?______________) ____ C7H17 + ____O2  ____ CO2 + ____ H2O * Hint: when you get stuck on these, double your carbons (and everything else) wherever you get stuck. Trust Me 

Snowman Challenge Rules From the snowmen choose 1 question at a time. If you pick it, you must solve it!! Copy the question into notebook, add spaces for balancing. Must show work!!! You must get each question right before choosing a new question. Do 10 questions for full credit, up to 15 for extra credit