Chemical Reactions Practice Flashcards

A comprehensive set of vocabulary flashcards based on Chapter 5 lecture notes regarding chemical changes, reaction indicators, and the components of chemical equations.

Physical change

A change that does not affect the identity of a substance; no chemical bonds are broken or formed.

Chemical change

A change that affects the identity of a substance; chemical bonds are broken and/or formed.

Chemical reaction

The process by which chemical change takes place, where one or more substances turn into different substances.

Exothermic reaction

A reaction during which energy is released, often resulting in an increase in temperature or the release of light.

Endothermic reaction

A reaction during which energy is absorbed, often detectable by a drop in temperature.

Precipitate

A solid that separates out of a solution as the result of a chemical change.

Reactants

The original substances in a chemical reaction, typically located on the left side of a chemical equation.

Products

The substances into which reactants change during a chemical reaction, typically located on the right side of a chemical equation.

Chemical equation

An equation using chemical formulas and symbols that describes a chemical reaction.

Aqueous solution

A solution in which a solid, liquid, or gas is dissolved in water, denoted by the symbol $(aq)$.

Chemical coefficient

The number in front of a compound in a chemical equation that represents the whole-number ratio of reactants and products.

Balanced equation

A chemical equation that contains the same count of atoms of each element on both sides of the arrow.

Law of Conservation of Mass

The principle stating that matter can neither be created nor destroyed; it merely changes form.

Catalyst

A substance that speeds up a chemical reaction without being consumed itself in the process; its symbol is written over the arrow in a chemical equation.

Diatomic elements

Seven elements that exist by themselves only in pairs: $H_2$, $N_2$, $O_2$, $F_2$, $Cl_2$, $Br_2$, and $I_2$.

BrINClHOF

A mnemonic used to remember the seven diatomic elements: Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine.

Greenhouse gases

Substances including carbon dioxide, methane, water, and ozone that trap heat from the Sun and hold it near the Earth.

Carbon cycle

The process where carbon dioxide absorbed by photosynthetic plants is released back to the atmosphere when organic matter burns, decays, or is used in respiration.

Sublimation

A physical change where a substance moves directly from a solid phase to a vapor phase, such as dry ice ($\text{solid } CO_2$) becoming a gas.