Describing Chemical Reactions

Learning Scale 4 – Investigate and describe the compounds formed by bonding elements. 3 – Describe why certain elements bond with others. 2 – Use the periodic table to identify the number of protons, neutrons, or electrons in an element. 1 – Identify patterns on the periodic table.

Classifying Chemical Reactions Synthesis – two or more elements combine to make a more complex substance. Decomposition – Compounds are broken into simpler products. Replacement – When one element replaces another in a compound

What type of reaction?

What type of reaction?

What type of reaction?

What type of reaction?

What type of reaction?

What are Chemical Equations? A chemical equation is a short, easy way to show a chemical reaction using symbols instead of words. A reactant is the substance you have at the beginning of the reaction (left of arrow). A product is the new substance that formed during the reaction (right of arrow)

Balancing Chemical Equations Write the equation. H2 + O2 H2O Count the atoms. H2 + O2 H2O 2 2 2 1

Use Coefficients to Balance the Atoms. 2 H2 +__ O2 2 H2O 4 2 4 2 Look Back and Check The left and right sides of the equation should be equal.

Law of Conservation of Mass The principle of conservation of mass states that in a chemical reaction, the total mass of the reactants must equal the total mass of the products.

Learning Scale 4 – Investigate and describe the compounds formed by bonding elements. 3 – Describe why certain elements bond with others. 2 – Use the periodic table to identify the number of protons, neutrons, or electrons in an element. 1 – Identify patterns on the periodic table.