Chapter 2; Definition Questions Flashcards
The Chemical Context of Life
Which is anything that takes up space and has mass.
Matter
A substance that cannot be broken down to other substances by chemical reactions.
Element
Two or more atoms held together by covalent bonds.
Molecule
A substance consisting of two or more different elements combined in a fixed ratio.
Compound
An organism needs to live a healthy life and reproduce.
Essential Elements
The smallest unit of matter that still retains the properties of an element.
Atom
Electrically neutral.
Neutron
One unit of positive charge.
Proton
One unit of negative charge.
Electron
Number of protons.
Atomic Number
Total mass of an atom.
Atomic Mass
The total number of protons and neutrons in the nucleus of an atom.
Mass Number
Different atomic forms of the same element.
Isotopes
A characteristic average distance and energy level.
Electron Shell
Outer electron.
Valence Electron
The sharing of a pair of valence electrons by two atoms.
Covalent Bond
In a covalent bond between two atoms of the same element, the electrons are shared equally because the two atoms have the same electronegativity.
Nonpolar Covalent Bond
When an atom is bonded to a more electronegative atom, the electrons of the bond are not shared equally.
Polar Covalent Bond
two resulting oppositely charged atoms or molecules.
Ion
Because of their opposite charges, cations and anions attract each other.
Ionic Bond
Noncovalent attraction between a hydrogen and an electronegative atom.
Hydrogen Bond
The making and breaking of chemical bonds, leading to changes in the composition of matter.
Chemical Reaction
The hydrogen bonds hold the substance together.
Cohesion
The clinging of one substance to another.
Adhesion
A liquid that is a completely homogeneous mixture of two or more substances.
Solution
The substance that is dissolved.
Solute
The dissolving agent of a solution.
Solvent
To repel water.
Hydrophobic
Any substance that has an affinity for water.
Hydrophilic
Is a substance that increases the hydrogen ion concentration of a solution.
Acid
A substance that reduces the hydrogen ion concentration of a solution.
Base
A solution is defined as the negative logarithm of the hydrogen ion concentration.
pH
A substance that minimizes changes in the concentration of H+ and OH- in a solution.
Buffer
