acid: a substance that tastes sour, reacts with bases, reacts with metals, and conducts electricity
base: a substance that tastes bitter, reacts with acids, feels slippery, and conducts electricity
carbon dioxide: a colourless gas; can be produced when an acid reacts with baking soda
chemical reaction/change: a reaction that results in the change of the original substances
indicator: a chemical substance that changes colour when exposed to an acid or a base
irreversible: impossible to be reversed (cannot be changed to its original state or conditions)
reversible: capable of being reversed (can be changed to its original state and conditions)
precipitate: a solid formed by the chemical reaction of two liquids
physical change: a change in the form or appearance of a substance
neutral: a substance that is neither acidic nor basic