A type of solid matter in which atoms or molecules do not have long-range order (e.g., glass and plastic).
The smallest identifiable unit of an element.
The amount of energy required to raise the temperature of 1 g of water by 1 °C.
An energy unit equivalent to 1000 little-c calories.
A change in which matter changes its composition.
The energy associated with chemical changes.
Properties that a substance can display only through changing its composition.
The process by which one or more substances transform into different substances via a chemical change. Chemical reactions often emit or absorb energy.
A substance composed of two or more elements in fixed, definite proportions.
Able to occupy a smaller volume when subjected to increased pressure. Gases are compressible because, in the gas phase, atoms or molecules are widely separated.
A type of solid matter with atoms or molecules arranged in a well-ordered, three-dimensional array with long-range, repeating order (e.g., salt and diamond).
Energy associated with the flow of electric charge.
A substance that cannot be broken down into simpler substances.
Describes a process that absorbs heat energy.
The temperature scale that is most familiar in the United States; water freezes at 32 °F and boils at 212 °F.
The quantity of heat energy required to change the temperature of a given amount of a substance by 1 °C.
A mixture, such as oil and water, that has two or more regions with different compositions.
A mixture, such as salt water, that has the same composition throughout.
The temperature scale that assigns 0 K to the coldest temperature possible, absolute zero (-273°C or -459°F), the temperature at which molecular motion stops. The size of the kelvin is identical to that of the Celsius degree.
Energy associated with the motion of an object.
A law stating that energy can be neither created nor destroyed. The total amount of energy is constant and cannot change; it can only be transferred from one object to another or converted from one form to another.
A state of matter in which atoms or molecules are packed close to each other (about as closely as in a solid) but are free to move around and by each other.
Anything that occupies space and has mass. Matter exists in three different states: solid, liquid, and gas.
A substance composed of two or more different types of atoms or molecules combined in variable proportions.
Two or more atoms joined in a specific arrangement by chemical bonds. A molecule is the smallest identifiable unit of a molecular compound.
A change in which matter does not change its composition even though its appearance might change.
Those properties that a substance displays without changing its composition.
The energy of a body that is associated with its position or the arrangement of its parts.
The final substances produced in a chemical reaction; represented on the right side of a chemical equation.
The characteristics we use to distinguish one substance from another.
A substance composed of only one type of atom or molecule.
The initial substances in a chemical reaction, represented on the left side of a chemical equation.
A state of matter in which atoms or molecules are packed close to each other in fixed locations.
The heat capacity of a substance in joules per gram degree celsius (J/g °C).
Tending to vaporize easily.