Key Terms 2 & 3 Flashcards
(26 cards)
Element
A substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of the same element have the same atomic number
Matter
Anything that has mass and takes up space
Atom
The smallest unit of an element that maintains the chemical properties of that element
Molecule
The smallest particle of a substance that has all the chemical properties of that substance; a molecule is made up of one atom or two or more atoms bonded together
Compound
A substance made up of atoms of two or more different elements joined by chemical bonds
Pure substance
A sample of matter, either a single element or a single compound, that has a definite physical and chemical properties
Mixture
A combination of two or more substances that are not chemically combined
Melting point
The temperature and pressure at which a solid becomes a liquid
Boiling point
The temperature and pressure at which a liquid and a gas are at an equilibrium
Density
The ratio of the mass of a substance to the volume of that substance; commonly expressed as grams per cubic centimeter for solids and liquids and as grams per liter for gases
Reactivity
The capability of of a substance to combine chemically with another substance
Physical change
A change of one form of matter to another without a change in chemical properties
Chemical change
A change that occurs when one or more substances change into entirely new substances with different properties
Fluid
A nonsolid state of matter in which the atoms or molecules are free to move past each other, as in a gas or a liquid
Plasma
In physical science, a state of matter that consists of free-moving ions and electrons; a plasma’s properties differ from that of a solid, liquid, or gas
Energy
The capability to do work
Temperature
A measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object
Thermal energy
The total kinetic energy of a substance’s atoms
Evaporation
The change of state from a liquid to a gas
Sublimation
The process in which a solid turns directly into a gas
Condensation
The change of state from a gas to a liquid
Pascal
The SI unit of pressure; equal to the force of 1N exerted over an area of 1 square meters (Pa)
Pressure
The amount of force exerted per unit area of a surface
Buoyant force
The upward force that keeps an object immersed or floating on a fluid
