Section 6.1

Chemical Equations

• Chemists use statements called equations to represent chemical reactions.

• Descriptions and observations are not enough to detail chemical reactions

Section 6.1

Chemical Equations

• A substance that undergoes a reaction is called a reactant.

• Each new substance formed from reactants reacting is called a product.

Section 6.1

Chemical Equations (cont.)

• Word equations are the simplest way to express chemical reactions in words

• Each reactant is separated by a plus (+) sign

• Each product is separated by a plus (+) sign

• Reactants and products are separated from each other by an arrow ( )

Section 6.1

Chemical Equations (cont.)

• Basic Format:

Reactant 1 + Reactant 2 Product 1 + Product 2

• Example:

Vinegar + baking soda sodium acetate + water+ carbon dioxide

Section 6.1

Chemical Equations (cont.)

• Scientific names can also be used

• Example:

acetic acid + sodium hydrogen carbonate → sodium acetate + water + carbon dioxide

Section 6.1

Chemical Equations (cont.)

• Chemical equations use symbols and formulas to represent the reactants and products.

• This tells you exactly what reacted, and what was formed.

• Example:

HC2H3O2 + NaHCO3 → NaC2H3O2 + H2O + CO2

Section 6.1

Chemical Equations (cont.)

• Symbols for states of matter:

• (s) solid

• (l) liquid

• (g) gas

• (aq) aqueous [in water solution]

Section 6.1

Chemical Equations (cont.)

• The state of matter directly follows the formula it describes.

• Example:

HC2H3O2 (aq) + NaHCO3 (s) → NaC2H3O2 (aq) + H2O (l) + CO2 (g)

Section 6.1

Examples of Chemical Equations

• Na (s) + H2O (l) NaOH (aq) + H2 (g)

• What are the reactants?

Na and H2O

• What are the products?

NaOH and H2