Chapter 2- The Chemical Basis of Life

Question 1

Atom

Answer 1

The smallest unit of matter that retains the properties of an element.

Question 2

Proton

Answer 2

Subatomic particle with a single positive electric charge.

Question 3

Electron

Answer 3

A subatomic particle with a single negative charge

Question 4

Neutron

Answer 4

A subatomic particle which is electrically neutral.

Question 5

Nucleus

Answer 5

An atoms central core made up of two protons and two neutrons.

Question 6

Atomic number

Answer 6

All atoms of a particular element have the same unique number of protons. This number is the element’s atomic number.

Question 7

Mass number

Answer 7

The number of protons and neutrons in an atoms nucleus.

Question 8

Atomic mass

Answer 8

Approximately equal to the mass number in daltons

Question 9

Isotopes

Answer 9

Have the same number of protons and behave identically in chemical reactions, but they have a different number of neutrons.

Question 10

Radioactive isotope

Answer 10

An isotope in which the nucleus decays spontaneously, giving off particles and energy.

Question 11

Electron shells

Answer 11

The circles where electrons are distributed around a nucleus

Question 12

Chemical bonds

Answer 12

The attraction between atoms with incomplete atomic shells that have given up, accepted or shared electrons with each other.

Question 13

Ionic bonds

Answer 13

The result of a transfer of an electron between atoms.

Question 14

Covalent bonds

Answer 14

Caused by atoms sharing electrons between each other.

Question 15

Molecule

Answer 15

Consists of two or more atoms held together by covalent bonds

Question 16

Electronegativity

Answer 16

Is a measure of an atoms attraction for shared electrons.

Question 17

Non polar covalent bonds

Answer 17

A covalent bond where the electrons are shared equally because the atoms have the same electronegativity.

Question 18

Polar covalent bond

Answer 18

A bond formed when atoms differ in electronegativity.

Question 19

Ion

Answer 19

An atom or molecule with an electric charge resulting from the gain or loss of one or more electrons.

Question 20

Salt

Answer 20

Synonym for an ionic compound.

Question 21

Hydrogen bond

Answer 21

The bond between water molecules. Fairly weak individually but incredibly strong en masse.

Question 22

Polar molecule

Answer 22

A molecule with an unequal distribution of charges.

Question 23

Reactants

Answer 23

The part of a chemical equation with the arrow emerging from it.

Question 24

Product

Answer 24

The part the arrow is pointing to.

Question 25

Cohesion

Answer 25

The tendency of molecules of the same kind to stick together.

Question 26

Adhesion

Answer 26

The clinging of one substance to another

Question 27

Surface tension

Answer 27

A measure of how difficult it is to stretch or break the surface of a liquid.

Question 28

Thermal energy

Answer 28

The energy associated with the random movement of atoms and molecules.

Question 29

Heat

Answer 29

Thermal energy in transfer from a warmer to a cooler body of matter.

Question 30

Temperature

Answer 30

Measures the intensity of heat aka the average speed of molecules in a body of matter.

Question 31

Evaporative cooling

Answer 31

When a substance evaporates and the surface of the liquid that remains behind cools down.

Question 32

Solution

Answer 32

A liquid consisting of a uniform mixture of two or more substances.

Question 33

Solvent

Answer 33

Any dissolving agent.

Question 34

Solute

Answer 34

Substance that is dissolved.

Question 35

Aqueous Solution

Answer 35

A solution in which water is the solvent

Question 36

Acid

Answer 36

A substance that donates hydrogen ions to a solution. An acidic solution has a higher concentration of H+ than OH-

Question 37

Base

Answer 37

A substance that reduces the hydrogen ion concentration of a solution.

Question 38

pH scale

Answer 38

A scale used to describe how acidic or basic a solution is. The scale ranges from 0 (most acidic) to 14 (most basic).

Question 39

Buffers

Answer 39

Substances that minimize changes in ph.

Question 40

Ocean acidification

Answer 40

CO2 dissolving in seawater lowers the ph of the ocean in this phenomenon. It destroys sea and Coral life.