Chapter 2

Question 1

Matter

Answer 1

anything that takes up space and has mass

Solid –> Liquid –> Gas–>Plasma

Question 2

Element

Answer 2

substance that cannot be broken down to other substances by chemical reactions

Question 3

Compound

Answer 3

a substance consisting of two or more different elements combined in a fixed ratio

Question 4

Essential Element

Answer 4

Elements needed by an organism for optimal health. Humans need 25, Plants only need 17 elements. Just 4 elements (O, C, H, and N) make up 96% of all living matter. The other 4% are mainly Ca, P, K, and S.

Question 5

Trace Elements

Answer 5

elements that are required by an organism in minute quantities (Fe, Mg, I…)

Question 6

Atoms

Answer 6

smallest unit of matter that still retains properties of the element

Question 7

Protons

Answer 7

has +1 charge, found in nucleus

Question 8

Neutron

Answer 8

has 0 charge, found in nucleus

Question 9

Electron

Answer 9

has -1 charge, found in electron cloud surrounding nucleus

Question 10

Atomic number

Answer 10

equal to number of protons, identifies element.

top left number on the periodic table of an element

Question 11

Mass Number

Answer 11

equal to number of protons + neutrons

Question 12

Isotopes

Answer 12

different forms of same element (have same # of protons, but different # of neutrons)

Question 13

Atomic Mass

Answer 13

average mass of all naturally occurring isotopes of an element

Question 14

Electron shells

Answer 14

region in which electron is likely to be found (average distance)

Question 15

Valence Electrons

Answer 15

electrons in the outermost electron shell when the e - is in the ground state

Question 16

Electronegativity

Answer 16

attraction of particular atom for the electrons in a covalent bond

Question 17

Weak Bonds

Answer 17

Biologically important in large quantities or large molecules

Question 18

Hydrogen Bond

Answer 18

attraction between a hydrogen (delta+) from one molecule and an electronegative atom (delta-) from another molecule - important for understanding water.

Question 19

Van der Waals Interactions

Answer 19

Occur from temporary dipoles when atoms are in close contact with other atoms or molecules. Individually weak, but strength in numbers.

Question 20

Chemical Reactions

Answer 20

conversion of starting materials (reactants) to products (some reversible)

a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

Question 21

Rate of reaction

Answer 21

increases with higher concentration of reactants, slows as products accumulate

the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.

Question 22

Chemical Equilibrium

Answer 22

in a reversible reaction, that dynamic stability in which there is no net change in amount of reactants or products

Question 23

Properties of water

Answer 23

Water has many unique properties that make it necessary for all living things. Water is the universal solvent - most ionic and polar substances dissolve in water. Cells are 70 - 95% water. Hydrogen bonds (H-bonds) are responsible for most of water’s remarkable properties

Question 24

Cohesion

Answer 24

water sticks to self (pulls water up plant)

cohesion refers to the sticking together of alike molecules, such as water molecule being attracted to another water molecule. Cohesion also causes water molecules to form drops. Together with adhesion, It helps to explain the occurrence of surface tension and capillarity. … cohesive attraction.

Question 25

Adhesion

Answer 25

water sticks to other substances

The binding of a cell to another cell, or a cell to a surface, via specific cell adhesion molecules

Question 26

High specific heat

Answer 26

moderates temperatures on earth

1 cal/g o C - moderates coastal climates, oceans/lakes have stable temperatures

Question 27

Heat of vaporization

Answer 27

the quantity of heat a liquid must absorb for 1g of it to be converted from the liquid to the gaseous state

Question 28

Evaporative cooling

Answer 28

perspiration keeps our bodies cool makes water vapor, which releases heat when it condenses into cloud

Question 29

Heat of Fusion

Answer 29

the heat absorbed by a unit mass of a given solid at its melting point that completely converts the solid to a liquid at the same temperature: equal to the heat of solidification.

Question 30

Floating Ice

Answer 30

Insulates the water below - protects aquatic life below. Water is less dense as a solid than as a liquid.

Question 31

Universal Solvent

Answer 31

many solutes dissolve in water to make a homogeneous aqueous solutions

Question 32

Hydration Shell

Answer 32

sphere of water molecules surrounds each particle of solute

Question 33

Solute Concentrations

Answer 33

Amount of solute in solvent: measured in Molarity (M) (number of mol/liter)

Question 34

Mol (mol)

Answer 34

a mole of any substance is equal to formula weight (from periodic table)

Question 35

OH-

Answer 35

hydroxide ion

Question 36

H+

Answer 36

hydrogen ion (aka proton)

Question 37

H3O+

Answer 37

Hydronium ion

Question 38

Base

Answer 38

reduces [H +], or produces OH-, raises pH

Question 39

pH

Answer 39

-log [H+] - measures the relative amount of H+ in solution
Most biological fluids have pH values in the range of 6 to 8
pH 7 is neutral (< 7 is acidic, > 7 is basic)
Acids and bases neutralize each other
Each pH unit represents a tenfold difference in H+ and OH − concentrations.

Question 40

Buffers

Answer 40

resist changes to the pH of a solution when H+ or OH − is added to the solution

Question 41

Acid precipitation

Answer 41

rain, snow, or fog has a pH that is more acidic than 5.6 (air pollution is cause)

Question 42

Ocean Acidification

Answer 42

harms marine ecosystems (burning fossil fuels, CO2 in atmosphere is cause)