Balancing Chemical Equations What goes in must come out!

Balancing Chemical Equations Balancing a chemical equation is much like the work of an accountant who has to show every penny that comes in and where it has gone to.

Objectives Learn the steps to balancing chemical equations. Take notes to help you understand. Test yourself with a set of equations to balance. Enter your own equations to see if they balance.

Law of Conservation of Mass You need to remember this law! The Law of Conservation of Mass states: that mass is neither created nor destroyed in any chemical reaction. Therefore balancing of equations requires the same number of atoms on both sides of a chemical reaction. The number of atoms in the Reactants must equal the Number of atoms in the Products

Chemical Equations Lavoisier, 1788 Because of the principle of the Conservation of Matter, an equation must be balanced. It must have the same number of atoms of the same kind on both sides.

A simple equation, such as the synthesis of Iron (II) sulfide, iron + sulfur Iron (II) sulfide Fe + S FeS Note that in a chemical equation, by convention, we use the arrow “ " instead of the equals “ = ".

Balancing Equations 2 3 ___ Al(s) + ___ Br2(l) ---> ___ Al2Br6(s)

Steps to Balancing a Chemical Equation Write all reactants on the left and all products on the right side of the equation arrow. Make sure you write the correct formula for each element 2. Determine how many atoms of each element are on each side of the arrow.

Steps to Balancing a Chemical Equation Find suitable coefficients, which are the numbers placed before formulas to indicate how many formula units of each substance are required to balance the equation. Start with trial and error by changing the coefficients to the smallest whole-number values. Check to make sure there are equal numbers of substances of each side.

Order for balancing equations Check for diatomic molecules. Balance the metals (not Hydrogen). Balance the nonmetals (not Oxygen). Balance oxygen. Balance hydrogen. The equation should now be balanced, but recount all atoms to be sure. Reduce coefficients (if needed).