Life's Chemical Basis Flashcards

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1
Q

matter

A

takes up space and has mass

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2
Q

basic ingredient of matter

A

element

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3
Q

element

A

substance that cannot be

broken down into other substances by chemical reactions (cannot be chemically broken down.) Found on periodic table.

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4
Q

compound

A

Two or more elements

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5
Q

4 most important elements (96% of living matter):

A

C, O, H, N (in order of amount)

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6
Q

Atom

A

smallest unit of an element

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7
Q

parts of atom

A

neutron, proton, electron

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8
Q

neutron

A

neutral charge, found in nucleus,

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9
Q

proton

A

positive charge, found in nucleus,

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10
Q

electron

A

negative charge, moves rapidly around the nucleus

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11
Q

valence shell

A

outermost shell of atom

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12
Q

What determines the reactivity of the atom with other atoms?

A

Number of electrons in valence shell

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13
Q

When will an atom be unreactive or reactive?

A

Unreactive if shell is full and vv

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14
Q

full valence shell

A

full=8 electrons

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15
Q

Chemical bonds

A

form when atoms with

incomplete valence shells interact to produce complete valence shells

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16
Q

Chemical reactions

A

break or form chemical bonds to

change reactants into products

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17
Q

law of conservation of matter

A

cannot be created or destroyed

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18
Q

What happens to matter during a reaction bc of the law of CoM?

A

conserved

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19
Q

Are chemical reactions reversible?

A

Most

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20
Q

When is chemical equilibrium reached?

A

when the forward and backward

reaction rates are equal

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21
Q

types of bonds

A

ionic, covalent (nonpolar and polar)

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22
Q

Ionic bonds-

A

form when electrons are

transferred from one atom to the other

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23
Q

ions

A

Resulting atoms of ionic bonds are called ions, and positive and
negative charges of ions?
(ion–charged atom/s)

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24
Q

covalent bonds

A

electrons are shared, occurs between two
atoms of
similar pulls on electrons

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25
Q

electronegativity–

A

pull on electron

26
Q

electronegativity trend

A

right and up on pd table-stronger electronegativity

27
Q

Nonpolar covalent

A

electrons are shared

equally–identical bond

28
Q

Polar covalent

A

electrons are shared unequally

29
Q

pole

A

charge

30
Q

significance of polar covalent bonds in charge

A

Bond is closer to atom with higher pull and

produces a negative charge, or pole, near that atom

31
Q

Where are slightly positive poles found?

A

area around atom w weaker pull

32
Q

H2O poles

A

O2 a slight negative charge–stronger pull on electron than hydrogen

33
Q

Hydrogen Bonds

A

weak bonds between molecules

34
Q

When do H bonds form?

A

Form when positively charged hydrogen atom in one

covalently bonded molecule is attracted to a negatively charged area of another covalently bonded molecule

35
Q

Example of H bonds

A

Example- in water molecules- helps in cohesion between

molecules

36
Q

Properties of Water due to H bonds

A

cohesion, adhesion, Capillary action, Surface tension, Versatile solvent, high heat of vaporization, high heat capacity

37
Q

cohesion

A

water is self attracted

38
Q

adhesion

A

water is attracted to other molecules

39
Q

Capillary action-

A

water can be pulled up thin tubes

against pull of gravity (combo of cohesion and adhesion)

40
Q

Ex of Capillary action-

A

meniscus–moves up sides of tube of graduated cylinder, forming a curve/meniscus–measure the bottom of meniscus; happens with water in trees-small tubes in plants used for transferring water. called xylem tubes, and since they have no pumping organ it can just move through physical means, including CA.

41
Q

Surface tension

A

the surface of water exposed to the air is

difficult to puncture–you can, but there’s an added resistance

42
Q

high heat capacity

A

compared to other substances, it takes

water a large amount of heat in order to raise its temp by 1d C

43
Q

Why does water have a high heat capacity

A

heat first needed to break H bonds, then the water molecules start moving faster.

44
Q

how does water’s high heat capacity help the environment?

A

helps minimize variations in atmospheric

temperature throughout the planet.

45
Q

high heat of vaporization

A

a lot of heat is required to

change water from a liquid to a gas

46
Q

Why does evaporation have a cooling effect on the environment?

A

high heat of vaporization–bc it takes heat to do, so it’s subtracting heat–same with sweat. we use heat to sweat, using it up from our bodies.

47
Q

Why does ice float on its surface?

A

ice is less dense than water (d=m/v
ice has more air spaces
H bonds always breaking and forming in water)

48
Q

Why is water a versatile solvent?

A

because of the fact that it
is polar-
it is attracted to other polar/charged substances and breaks them apart
the charges can help draw the molecules of opposite charge apart to dissolve

49
Q

solvent

A

dissolves other substances easily

50
Q

Why is ice less dense than water

A

This is due to the fact that when the water molecules slow down,
each water molecule forms four permanent H bonds to other water
molecules,
spreading out molecules + creating air spaces

51
Q

What does ice’s less dense status allow for during the winter?

A

This allows bodies of water to have a protective insulating layer on
top during the winter time.

52
Q

solute

A

gets dissolved

53
Q

Hydrophilic substances-

A

attracted to water–polar or charged

54
Q

hydrophobic substances

A

repels water-non-polar substances

55
Q

H+ ion interchangeable with…

A

H+ ion interchangeable with a proton

56
Q

Why is water neutral?

A

neutral bc H+ and OH- amounts are equal

57
Q

alkaline

A

alkaline=base

58
Q

What two ions can water dissociate into?

A

OH-, base, hydroxide ion, and H+, hydrogen ion, acid (same as hydronium ion when sometimes it attaches off)

59
Q

pH

A

The concentration of H+ ions is measured in pH units. Each pH unit
increase is tenfold difference in H+ ion concentration
10*, not 10+!!!!

60
Q

pH range

A

pH ranges from 0 (most acidic) to 14 (most basic)

61
Q

Neutral solution

A

has equal H+ and OH- pH of 7. The internal pH of

most living cells must be kept close to 7.

62
Q

pH of 4

A

pH of 4 = 1* 10^-4, or .0001 H+ ions

exponent is pH