Balancing Chemical Equations

Learn to balance chemical equations! Practice identifying reactants and products, applying conservation of mass.

Atoms can’t ever be created or destroyed in a chemical reaction. The atoms must always be equal on each side of the equation. What is the term used for the elements and compounds before a chemical reaction takes place? What is the term used for the elements and compounds after a chemical reaction takes place? How do you know when a chemical equation is balanced? The law of conservation of mass states that matter cannot be created or destroyed. It can only be rearranged to form a new substance. The elements or compounds on the left side of the reaction are called reactants. On the right side they are called products. An easy way to remember this is RAP (Reactants, Arrow, Products). Sort the following elements and compounds into the correct category. The equation should show oxygen and hydrogen combining to form water. Reactants Products Sort the following reactions into the balanced or unbalanced categories Balanced Unbalanced Which compounds represent the product(s) in the following equation?C3H8 + 5O2 → 4H2O + 3CO2 C3H8 5O2 Only 4H2O Both 4H2O and 3CO2 Which is not true about the law of conservation of mass? Nothing is created The same number of atoms are inboth the products and reactants New atoms are created when a new substance is formed Nothing is destroyed Is the following equation balanced or unbalanced?P4 + 3Br2→ 2PBr3 Balanced Unbalanced Is the following equation balanced or unbalanced?AlBr3 + 3K → 3KBr + Al Balanced Unabalnced Balancing Equations Click on the blue dots to enter the coefficient(s) that balances this equation. 4 1 2 2 2 1 2 3 2 4 2 3