Biology chapter 2 vocab

Compound- a substance made up of atoms of two or more different elements joined by chemical bonds.

Chemical bond- the attractive force that holds atoms or ions together.

Covalent bond- a bond formed when atoms share one or more pairs of electrons.

Molecule- a group of atoms that are held together by chemical forces; the smallest unit of matter that can exist by itself and retain all of a substance's chemical properties.

Ion- an atom, radical, or molecule that has gained or lost one or more electrons and has a positive or negative charge.

Ionic bond- the attractive force between oppositely charged ions, which form when electrons are transferred from one atom to another.

Energy- the capacity to do work

Chemical reaction- the process by which one or more substances change to produce one or more different substances.

Matter- Anything that has mass and takes up space

Mass- a measure of the amount of matter in an object; a fundamental property of an object that is not affected by the forces that act on the object, such as the gravitational force.

Element- a substance that cannot be separated or broken down into simpler substances by chemical means; all atoms of an element have the same atomic number.

Atom- the smallest unit of an element that maintains the chemical properties of that element.

Nucleus- an atom's central region, which is made up of protons and neutrons.

Proton- A subatomic particle that has a positive charge and that is found in the nucleus of an atom.

Neutron- a subatomic particle that has no charge and is located in the nucleus of an atom.

Atomic number- the number of protons in the nucleus of an atom

Mass number- the sum of the numbers of protons and neutrons in the nucleus of an atom.

Electron- A subatomic particle that has a negative charge

Orbital- a region in an atom where there is a high probability of finding electrons.

Isotope- an atom that has the same number of protons (or the same atomic number) as other atoms of the same element do but that has a different number of neutrons (and thus a different atomic mass).Reactant

a substance or molecule that participates in a chemical reaction.

Product- a substance that forms in a chemical reaction

Metabolism- the sum of all chemical processes that occur in an organism.

Activation energy- the amount of energy needed to start the chemical reaction.

Catalyst- a substance that changes the rate of a chemical reaction without being consumed or changed significantly.

Enzyme- a type of protein or RNA molecule that speeds up metabolic reactions in plant and animals without being permanently changed or destroyed.

Redox reaction- a reaction in which electrons are transferred between atoms; also known as an oxidation-reduction reaction.

Oxidation reaction- a chemical reaction in which a reactant loses one or more electrons such that the reactant becomes more positive in charge.

Reduction reaction- a chemical change in which electrons are gained, either by the removal of oxygen, the addition of hydrogen, or the addition of electron

Polar- describes a molecule with opposite charges on opposite ends.

Hydrogen bond- the intermolecular force occurring when a hydrogen atom that is bonded to a highly electromagnetic atom of one molecule is attracted to two unshared electrons of another molecule.

Cohesion- the force that holds molecules of a single material together.

Adhesion- the attractive force between two bodies of different substances that are in contact with each other.

Capillary- a tiny blood vessel that allows an exchange between blood and cells in tissues.

Solution- a homogeneous mixture throughout which two or more substances are uniformly dispersed.

Solute- in a solution, the substance that dissolves in the solvent.

Solvent- In a solution, the substance in which the solute dissolves.

Concentration- the amount of a particular substance in a given quantity of a mixture, solution, or ore.

Saturated solution- a solution that cannot dissolve any more solute under the given conditions.

Aqueous solution- a solution in which water is the solvent

Hydroxide ion- the OH- ion

Hydronium ion- an ion consisting of a proton combined with a molecule of water; H3O+.

Acid- any compound that increases the number of hydronium ions when dissolved in water

Base- any compound that increases the number of hydroxide ions when dissolved in water

pH scale- a range of values that are used to express the acidity or alkalinity (basicity) of a system; each whole number on the scale indicates a tenfold change in acidity; a pH of 7 is neutral, a pH of less than 7 is acidic, and a pH of greater than 7 is basic.

Buffer- a solution made from a weak acid and its conjugate base that neutralizes small amounts of acids or bases added to it.