1. Balancing Acts -Chemical Reactions & Balancing chemical equations Notes

2. Chemical Reactions
A chemical reaction is a chemical change that produces a new substance
Involves breaking old bonds and forming new bonds.
The chemical reaction is represented by using a chemical equation.

3. Conservation of Mass/Matter
Matter is not created or destroyed, just changed
In a chemical reaction the amount of matter that you begin with must be EQUAL to what you end with.
This is why chemical equations must be balanced.

4. Chemical Equations
Atoms are not CREATED or DESTROYED during a chemical reaction.
there must be the SAME number of atoms on each SIDE of the EQUATION.
To balance the chemical equation, you must add COEFFICIENTS in front of the chemical formulas in the equation.
You cannot add or change SUBSCRIPTS!

5. Steps to balancing chemical equations:
Determine the number of atoms for each element:
Mg + O2 --- MgO
Mg = 1 Mg = 1
O = 2 O = 1

6. 2: Pick an element that is not equal on both sides of the equation
2: Pick an element that is not equal on both sides of the equation. Mg + O2 --- MgO Mg = 1 Mg = 1 O = 2 O = 1
(since O atoms aren’t equal start here)

7. 3: Add a coefficient in front of the formula with that element and adjust your counts. Mg + O2 --- 2MgO Mg = 1 Mg = 1 2 O = 2 O = 1 2
Adding a 2 in front of MgO will change the number of atoms on the product side.

8. 4.Continue adding coefficients to get the same number of atoms of each element on each side. 2Mg + O2 --- 2MgO Mg = 1 2 Mg = 1 2 O = 2 O = 1 2
Now we need to increase the number of Mg atoms on the reactant by adding a coefficient of 2.

9. H2 + O2 --- H20
H = 2 H =2
0 = 2 O =1