Acid-Base Reactions & Law of Conservation

of MatterOctober 3, 2011

What is an acid?Acids are compounds that accept electrons

from other chemicals known as bases.Many acids contain hydrogen.Acids taste sour, conduct electricity, and

often react with metals to release hydrogen gas.

We measure the strength of acids with the pH scale. Very strong acids have a pH of 0. Weak acids have a pH of 6.

What is a base?A base is a compound that donates electrons

to an acid.Bases taste bitter, are slippery, and conduct

electricity.We measure the strength of bases with the

pH scale. Very strong acids have a pH of 14. Weak bases have a pH of 8.

The pH scale

Indicators like litmus paper and phenolphthalein can identify chemicals as acids or bases

Acid-Base ReactionsWhen acids and bases react, they neutralize

each other.The products are generally salt and water.Energy is often released as heat.

Exothermic reactions – heat is produced or released during the reaction

Law of Conservation of MatterMatter can be neither created nor destroyed.The mass of the reactants of a reaction must

be equal to the mass of the products of a reaction.2g H2 + 16g O2 -> 18g H2O

The numbers of atoms of each element in the reactants must be equal to the numbers of atoms of each element in the products.2 H2 + O2 -> 2H2O

Law of Conservation of MatterThe numbers of atoms of each element in the

reactants must be equal to the numbers of atoms of each element in the products.2 H2 + O2 -> 2H2O

Atoms in Reactants Atoms in Products

H O H O