General Chemistry and Chemical Reactions Review

Antoine Lavoisier

Known as the Father of Modern Chemistry; formulated the Law of Conservation of Mass, helped establish modern chemical nomenclature, and explained the role of oxygen in combustion.

Dmitri Mendeleev

Scientist who developed an early periodic table of elements and predicted the existence and properties of undiscovered elements.

John Dalton

Scientist who developed an early modern atomic theory and explained that matter is made up of atoms.

Robert Boyle

Scientist known for Boyle's law; helped establish chemistry as an experimental science and studied the relationship between gas pressure and volume.

Marie Curie

Conducted pioneering research on radioactivity, helped discover polonium and radium, and was the first woman to win a Nobel Prize.

J. J. Thomson

Scientist who discovered the electron in 1897 and proposed the plum pudding model of the atom.

Ernest Rutherford

Scientist who proposed the nuclear model of the atom and conducted the gold foil experiment.

James Chadwick

Scientist who discovered the neutron in 1932.

Joseph Priestley

Experimentally isolated oxygen in 1774, independently of Carl Wilhelm Scheele; his work helped scientists understand gases.

Atom

The basic unit of a chemical element.

Element

A pure substance made of one type of atom.

Periodic Table

An organized arrangement of chemical elements.

Radioactivity

The spontaneous emission of radiation from unstable atomic nuclei.

Electron

A negatively charged subatomic particle.

Neutron

A subatomic particle with no electric charge.

Atomic Theory

A scientific explanation of the nature and behavior of atoms.

Law of Conservation of Mass

The principle stating that matter (or mass) is not created or destroyed during a chemical reaction in a closed system.

Reactants

Substances present before a chemical reaction.

Products

New substances formed by a chemical reaction.

Chemical Equation

A symbolic representation of a chemical reaction.

Observable Signs of a Reaction

Possible evidence of a reaction, including gas bubbles, color changes, temperature changes, light, or formation of a solid.

Combination Reaction

A reaction where two or more substances form one product ($A + B = AB$, such as $2Mg + O_2 = 2MgO$).

Decomposition Reaction

A reaction where one compound breaks down into simpler substances ($AB = A + B$, such as $CaCO_3 = CaO + CO_2$).

Acid-Metal Reaction

A chemical reaction following the general form $\text{Acid} + \text{metal} \rightarrow \text{salt} + H_2$, with the example $2HCl + Mg \rightarrow MgCl_2 + H_2$.

Acid-Carbonate Reaction

A reaction in which an acid reacts with a carbonate or bicarbonate to produce a salt, water, and carbon dioxide ($\text{Acid} + \text{carbonate} \rightarrow \text{salt} + H_2O + CO_2$), such as vinegar reacting with baking soda.

Combustion

A process where a substance reacts with oxygen and releases energy as heat and often light ($\text{Fuel} + \text{oxygen} \rightarrow \text{products} + \text{energy}$, such as $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$).

Hydrocarbon Combustion (Daily Life)

LPG burns to provide heat for cooking. Complete combustion produces carbon dioxide and water, whereas incomplete combustion can produce poisonous carbon monoxide.

Photosynthesis

The process where plants use sunlight, carbon dioxide, and water to produce glucose and oxygen ($CO_2 + H_2O \rightarrow \text{glucose} + O_2$).

Cellular Respiration

The process by which cells break down glucose, usually using oxygen, to release usable energy.

Rusting

A form of corrosion affecting iron where iron reacts with oxygen in the presence of moisture to form rust; water and oxygen help iron rust, while painting and coating metal can help prevent it.

Fermentation

A process where microorganisms such as yeast break down sugars and produce substances such as carbon dioxide or alcohol, depending on the process.

Ozone Formation

Ozone in the stratosphere absorbs much of the Sun's harmful ultraviolet radiation; certain pollutants, including CFCs, can destroy ozone.

Ocean Acidification

The process where the ocean absorbs carbon dioxide and dissolved $CO_2$ forms carbonic acid, lowering seawater pH and making it harder for corals and shell-forming organisms to build their structures.

Nitrogen Fixation

The process where certain bacteria convert atmospheric nitrogen into usable nitrogen compounds, which helps plants grow and supports agriculture.

Carbon Cycle

The movement of carbon among the atmosphere, organisms, oceans, and Earth through processes such as photosynthesis, respiration, decomposition, and combustion.

Saponification

The process in which fats or oils react with a strong base to produce soap and glycerol.

Baking (Baking Soda Reaction)

A culinary process where baking soda releases carbon dioxide bubbles upon reacting with an acid or through heat decomposition, helping bread and cakes rise.

Oxidation

The loss of electrons.

Reduction

The gain of electrons.

Catalyst

A substance that speeds up a reaction without being consumed overall.

Activation Energy

The energy needed to initiate a reaction.

Endothermic

A term describing a process or reaction that absorbs energy.

Exothermic

A term describing a process or reaction that releases energy.

Precipitate

An insoluble solid formed in a solution.

pH

A measure that indicates how acidic or basic an aqueous solution is.

Decomposers

Organisms that recycle nutrients by breaking down dead matter.

Surfactant

A substance found in soaps and detergents that helps water spread, lift, and remove oily dirt and grease from surfaces.

Fluoride

An ingredient commonly found in toothpaste that helps strengthen tooth enamel and prevent