Chemical Reactions

Chemical Reactions

• A chemical reaction is a process in which atoms are rearranged into different molecules.

• A reaction results in the formation of new materials with different properties from the original.

Law of Conservation of Matter

• Matter is neither created nor destroyed in a chemical reaction.

• All reactions begin and end with the same number of atoms

• This Law explains why chemical equations must be balanced

Arrows in a Reaction

• Sideways arrow = direction of a reaction is indicated by a sideways arrow

• Up arrow = a gas is produced, such as carbon dioxide (CO₂)

• Down arrow = a precipitate is produced, such as calcium carbonate (CaCO₃ )

Important Commodities

• Chemical reactions create important commodities (items that are bought and sold):

–Nylon, plastics, soaps, foods, building materials

New Chemicals

Baking soda

• Chemical Name: sodium bicarbonate

• Chemical Symbol: NaHCO₃

• A common household chemical used as a leavening agent in cooking (makes baked goods rise)) and as an antacid

Calcium Chloride

• Chemical symbol: CaCl₂

• A salt closely related to table salt but has no place in the diet

• Used to melt ice on roads

Citric Acid

• Chemical symbol: C₆H₈O₇

• An acid that comes from organic sources such as fruits

• It is a food additive that gives a tangy taste (lemon heads, sweet tarts).

• It can cause irritation if it gets in the eyes or nose.