Playlist: Chemical Reactions
What do fireworks, a fried egg, and a rusting truck have in common? They all involve chemical reactions. This program illustrates the mechanics of chemical reactions in five sections: Chemical Reactions (reactants and products, state changes, diatomic elements and molecules, Law of Conservation of Mass); Chemical Bonding (Octet Rule, ionic and covalent bonds); Types of Chemical Reactions (synthesis and decomposition reactions, single and double displacement reactions, acid/base reactions, exothermic and endothermic reactions); Reaction Rates (moles, kinetic energy, solutes and solvents, catalysts, activators and inhibitors, enzymes); and Reactions All Around Us (photosynthesis and chemosynthesis, autotrophs and photoautotrophs, bioluminescence). A viewable/printable instructor’s guide is available online. A Films for the Humanities & Sciences Production. A part of the series Essential Chemistry. (28 minutes)
During a chemical reaction, a new substance is formed. Fireworks, a rusting vehicle, and frying eggs involve chemical reactions. Changes in state (e.g. liquid to gas) always involve a physical change.
The mass of all reactants will always add up to the total mass of the products.
Chemical reactions rearrange the elements in the reactants to form different groupings of those same elements in the new products. Electrons are the key players in chemical bonding. Ionic bonds form between two or more ions that bond.
Many chemical reactions follow predictable patterns. Reaction types include synthesis, decomposition, single displacement, double displacement, and acid/base reactions.
Combustion reactions can be exothermic or endothermic. Both types are demonstrated. Photosynthesis is an endothermic chemical reaction. Laboratory safety is addressed.
The speed of a chemical reaction is called its reaction rate. The product of a chemical reaction is measured in grams, kilograms, or moles.
Variables affecting reaction rate include temperature, pressure, and reactant particle size.
A catalyst is a chemical that can speed up a chemical reaction without being involved in the reaction itself. Enzymes are biological catalysts that assist digestion and energy production.
Life depends on chemical reactions such as those involved in digestion and photosynthesis. Autotrophs, photoautotrophs, and the process of chemosynthesis use light or chemical energy to make their own food.