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Balancing Chemical Equations. Mrs. Pagano Physical Science 10 CP. What are Chemical Equations?. A chemical equation is an equation that uses the chemical formulas of the atoms being combined in the chemical reaction. Chemical Equation Example. The chemical equation for
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Balancing Chemical Equations Mrs. Pagano Physical Science 10 CP
What are Chemical Equations? • A chemical equation is an equation that uses the chemical formulas of the atoms being combined in the chemical reaction
Chemical Equation Example • The chemical equation for Methane + Oxygen = Carbon Dioxide + Water Is written CH4 + O2 CO2 + H2O
Reactants and Products • CH4 + O2 CO2 + H2O In a chemical equation, the chemical formulas written on the left side of the arrow are called Reactants The reactants form the Products which are written on the right side of the arrow “Give” or “Yield” Reactants Products
Balanced Chemical Equations • In order for a chemical equation to be balanced, the amount of atoms of each element on the right-hand side of the equation must match the number of atoms of each element on the left.
Is this Chemical Equation Balanced? • K + H2O KOH2 4 atoms 4 atoms
What About This One? • 2K + 2H2O 2KOH + H2 8 atoms 8 atoms Subscript Coefficient = 2 (K)
Conservation of Mass • All chemical equations must be balanced to follow the Law of Conservation of Mass
The Conservation of Mass Cont. • 2Mg + O2 2MgO • Notice that there are equal numbers of magnesium and oxygen atoms in the product and the reactants in the equation above • The total mass of the reactants will always equal the total mass of the product/s in a balanced equation =The Conservation of Mass Law
Let’s Try One Together • Identify the reactants and products and write the chemical formula for: Magnesium and oxygen react to form magnesium oxide Mg + O MgO Reactants Products
Balance the Equation One Atom at a Time Mg + O2 MgO
So, How Do We Balance Oxygen? Mg + O2 MgO There are two atoms of oxygen on the left, but only one on the right. To get the correct number of oxygen atoms on the product side we need to add a coefficient of 2 to MgO Mg + O22 MgO
Now We Need To Balance Mg 2Mg + O2 2MgO We have to add another coefficient to Mg on the left side to equal the amount of atoms on the right side. Adding the coefficient 2 will give us the correct number of magnesium atoms on both sides.
Last Step: Confirm the Equation is Balanced 2Mg + O2 2MgO