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Flashcards in Chapter 2 Deck (72):
1

anything that occupies space and has mass

Matter

2

An element that occurs in organisms in very small quantities (less than 0.01%); in nutrition, a mineral required by organisms only in small amounts

Trace Elements

3

Carbon, Hydrogen, Oxygen, Nitrogen, Calcium, Phosphorus, Sulfur, Sodium, Chloride, Magnesium, Potassium

Common Elements

4

The smallest unit that retains the chemical and physical properties of an element

Atoms

5

A unit composed of atoms combined chemically in fixed numbers and ratios

molecules

6

The name of a molecule written in chemical shorthand

formula

7

A molecule whose component atoms are different

compounds

8

The nucleus of an atom containing protons and neutrons

Atomic nucleus

9

negatively charged particle outside the nucleus of an atom

electrons

10

positively charged particle in the nucleus of an atom

protons

11

The number of protons in the nucleus of an atom

atomic number

12

uncharged particle in the nucleus of an atom

neutrons

13

a distinct form of the atom of an element with the same number of protons but different number of neutrons

isotopes

14

A standard unit of mass about 1.66x10^-24 grams

Dalton (Da)

15

The total number of protons and neutrons in the atomic nucleus

mass number

16

The amount of mater in an object

mass

17

a measure of the pull of gravity on an object

weight

18

the giving off of particles of matter and energy by decaying nuclei

radioactivity

19

an unstable, radioactive isotope

radioisotope

20

isotope used to label molecules so that they can be tracked as they pass through biochemical reactions

tracers

21

the region of space where the electron "lives" most of the time

orbital

22

regions of space within an atom where electrons are found

energy levels or shells

23

an electron in the outermost energy level of an atom

valence electrons

24

link formed when the atoms of reactive elements combine into molecules

chemical bonds

25

bond that results from electrical attractions between atoms that have lost or gained electrons
Na + Cl = NaCl
1. exert attractive force over great distance 2. attractive force extends in all directions 3.vary in strength depending on the presence of other charged substances

ionic bond

26

a positively or negatively charged atom

ions

27

a positively charged ion

cation

28

a negatively charged ion

anion

29

bond formed by electrons sharing between atoms

covalent bonds

30

the measure of an atom's attraction for the electrons it shares in a chemical bond with another atom

electronegativity

31

bond in which electrons are shared equally

nonpolar covalent bond

32

bond in which electrons are shared unequally

polar covalent bonds

33

association that occurs when polar molecules attract and align themselves with other polar molecules and with charged ions and molecules

polar associations

34

associations that occurs when nonpolar molecules clump together

nonpolar associations

35

in chemistry and biology, referring to polar molecules that associate readily with water

hydrophilic

36

in chemistry and biology, referring to nonpolar substances that are excluded by water and other polar molecules

hydrophobic

37

noncovalent bond formed by unequal electron sharing between hydrogen atoms and oxygen, nitrogen, or sulfur atoms

hydrogen bond

38

BETWEEN atoms in the SAME molecule

intramolecular

39

BETWEEN atoms in DIFFERENT molecules

intermolecular

40

weak molecular attractions over short distances

Van der Waals forces

41

a reaction that occurs when atoms or molecules interact to form new chemical bonds or break old ones

chemical reactions

42

the atoms or molecules entering a chemical reaction

reactants

43

an atom or molecule leaving a chemical reaction

product

44

a chemical reaction written in balanced form

chemical equations

45

an arrangement formed when a water molecule in liquid water establishes an average of 3.4 hydrogen bonds with its neighbors

water lattice

46

a rigid, crystalline structure formed when a water molecule in ice forms 4 hydrogen bonds with neighboring molecules

ice lattice

47

the amount of heat required to increase the temperature of a given quantity of water

specific heat

48

the amount of heat required to raise 1 g of water by 1 degree C

calories (cal)

49

the heat required to give water molecules enough energy of motion to break loose from liquid water form a gas

heat of vaporization

50

the high resistance of water molecules to separation

cohesion

51

the adherence of molecules to the walls of conducting tubes, as in plants

adhesion

52

the force that places surface water molecules under tension, making them more resistant to separation than the underlying water molecules

surface tension

53

a membrane with 2 molecular layers

bilayer

54

a surface coat of water molecules that covers other polar and charged molecules and ions

hydration layer

55

substance formed when molecules and ions separate and are suspended individually, surrounded by water molecules

solution

56

the water in a solution in which the hydration layer prevents polar molecules or ions from reassociating

solvent

57

the molecules of a substance dissolved in water

solute

58

the number of molecules or ions of a substance in a unit volume of space

concentration

59

the weight of an element in grams equal to the mass number

atomic weight

60

6.022x10^23
derived by dividing the atomic weight of any element by the weight of an atom of that element

avogadro's number

61

the weight of a molecule in grams, equal to the total mass number ofits atoms

molecular weight

62

amount of substance that contains as many atoms or molecules as there are atoms in exactly 12 g of carbon-12, which is Avogadro's number

mole (mol)

63

The number of moles of a substance dissolved in 1 L of solution

molarity (M)

64

the separation of water to produce hydrogen ions and hydroxide ions

dissociate

65

the term indicating that a reaction may go from left to right or from right to left, depending on conditions

reversible

66

proton donor that releases H+ (and anions) when dissolved in water

acids

67

Proton acceptor that reduces the H+ concentration of a solution

base

68

the concentration of H+ in a water solution, as compared with the concentration of OH-

acidity

69

the numerical scale used by scientists to measure acidity

pH scale

70

rainfall with low pH 3, primarily created when gaseous sulfur dioxide(SO2) dissolves in water vapor in the atmosphere, forming sulfuric acid

acid precipitation

71

substance that compensates for pH changes by absorbing or releasing H+

buffers

72

A pure substance that cannot be broken down into simpler substances by ordinary chemical or physical techniques

Element