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Biology 1000 > Unit 2-Chemistry > Flashcards

Unit 2-Chemistry Flashcards

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1
Q

Define matter

A

Anything that occupies space and has mass. Found on earth in three physical states : solid liquid and gas

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2
Q

Define elements

A

A substance that cannot be broken down to other substances by ordinary chemical means

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3
Q

What are the four common elements

A

Oxygen
Carbon
Hydrogen
Nitrogen

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4
Q

Define a molecule

A

Formed when two or more atoms are joined chemically

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5
Q

Define a compound

A

A substance consisting of two or more different elements combined in a fixed ratio
More common then pure elements

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6
Q

Define an atom

A

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

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7
Q

Define a proton

A

A subatomic particle with a single positive electrical charge

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8
Q

Define an electron

A

A subatomic particle with a single negative charge

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9
Q

Define a neutron

A

Has no charge

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10
Q

Define atomic number

A

Number of protons in a molecule

Note it’s also the number of electrons

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11
Q

Define mass number

And atomic mass

A

The sum of the number of protons and neutrons in its nucleus
Protons and neutrons pretty much weigh the same
Atomic mass is approximately equal to its mass number

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12
Q

What are two types of ions

A

Cations (+)

Anions (-)

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13
Q

Define isotopes

A

When an element has the same number of protons and behave identically in chemical reactions but they have different numbers of neutrons

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14
Q

Example of isotopes

A 
Carbon isotopes 
Carbon 12 (6 neutrons)
Carbon 13 (7 neutrons)
Carbon 14 (8 neutrons) 
But they all have the same number of protons (6)
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15
Q

Stable isotopes

A

Their nuclei remain intact more or less forever

Ex) C12 an C13

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16
Q

Radioactive isotopes

A

When the nucleus decays spontaneously giving off particles and energy
Can cause damage
Ex) C14

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17
Q

Define electron shells and valence shells

A

Electron shells= what electrons orbit on

Valence shell= the number of electrons in the outermost shell

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18
Q

What do valence shells determine

A

The chemical properties of an atom

Atoms whose outer shells are not full tend to interact with other atoms

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19
Q

How do chemical interactions between atoms enable them to fill their outer electron shells

A

When two atoms with incomplete outer shells react each atom will share donate or receive electrons so that both partners end up with completed outer shells

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20
Q

Chemical bonds

A

An attraction that holds atoms close together

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21
Q

What is the strongest kind of chemical bond

A

Covalent bond

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22
Q

Define covalent bonds

A

Two atoms share one or more pairs of outer shell electrons

This forms a molecule

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23
Q

What is a single covalent bond

A

The sharing of a pair of electrons

1 electron from each atom

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24
Q

How many covalent bonds can an atom form?

A

It depends on the number of additional electrons needed to fill its outer(valence) shell
Ie a double bond

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25
Q

Define electronegativity

A

An atoms attraction for shared electrons

The more electronegative an atom the more strongly it pulls shared electrons toward its nucleus

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26
Q

Define non polar covalent bonds and give examples

A

Electrons are shared equally between the atoms
Ex) O2 and H2 the two identical atoms exert an equal pull
Methane is non polar because carbon and hydrogen are not much different in electronegativity

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27
Q

What is one of the most electronegative elements

What does this make this atom

A

Oxygen
(Also nitrogen)
Oxygen attracts the shared electrons more strongly
A polar covalent bond

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28
Q

Define a polar covalent bond

Give an example

A

The pulling of shared negatively charged electrons closer to the more electronegative atom makes that atom partially negative and the other atom partially positive
H2O

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29
Q

Define a polar molecule

Give an example

A

Has an unequal distribution of charges
Negative at water end
Positive at hydrogen end

30
Q

Define an ion

A

An atom or molecule with an electrical charge resulting from a gain or loss of one or more electrons

31
Q

Define an ionic bond

Give an example

A

When an attraction holds two ions with opposite charges together to fill the outer electron shell
Electron donations
Crystal

32
Q

Define hydrogen bond

What type of strength are these

A

When the positively charged region in this type of bond is always hydrogen then we call it a hydrogen bond
A hydrogen atom that has formed a polar covalent bond with an electronegative atom had a partial positive charge
Weak bonds

33
Q

What enables neighbouring water molecules to hydrogen bond to one another

A

The molecules are polar with the negative end (oxygen) of one molecule attracted to a positive end (hydrogen) of its neighbour

34
Q

Define chemical reaction

A

The breaking and making of chemical bonds leading to changes in the composition of matter
Do not create or destroy matter

35
Q

Define reactants

A

Beginning materials of a chemical reaction

36
Q

Define products

A

The material resulting from the chemical reaction

37
Q

Define cohesion

A

When molecules of the same kind stick together and is much stronger for water.
Hydrogen bonds between water

38
Q

Define adhesion

A

The clinging of one substance to another

39
Q

Define heat

A

The amount of energy associated with the movement of atoms and molecules in a body of matter

40
Q

Define temperature

A

Measures the intensity of heat. The average speed of molecules rather then the total amount of heat energy in a body of matter

41
Q

Define evaporation

A

Occurs because the molecules with the greater energy leave

42
Q

Define a solution

A

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

43
Q

Define a solvent

A

The dissolving agent

44
Q

Define a solute

A

A substance that is dissolved

45
Q

Define an aqueous solution

A

When water is the solvent

46
Q

What are the two ions formed from dissociation of water

A 
Hydroxide ions (OH-)
Hydrogen ions (H+)
They are both very reactive
47
Q

Define acids

A

More H+ ions

A compound that donates hydrogen ions

48
Q

Define a base

A

A compound that accepts hydrogen ions and removes them
Donates OH- and that combined with the H+ to form H2O
Less H+ ions
More OH-

49
Q

Define a pH scale

A 
A scale used to describe how acidic or basic a solution is 
Ranges from 0-14 
0-6= acid
7= neutral 
8-14= basic 
Each notch is x10 H+
50
Q

Changing the ___ would change it into an atom of a different element

A

Number of protons in the nucleus of an atom

51
Q

Your body contains the smallest amount of which element

A

Phosphorus

52
Q

A solution at pH 6 contains ___ then the same amount of a solution at pH 8

A

100 X more H+

53
Q

Most of the unique properties of water result from the fact that water molecules __

A

Are polar and form hydrogen bonds

54
Q

A sulphur atom has 6 electrons in its outer shell. As a result it forms __ covalent bonds with other atoms

A

Two

55
Q

What does the word trace mean when you’re talking about a trace element

A

The element is required in very small amounts

56
Q

A can of cola consists mostly of sugar dissolved in water with some carbon dioxide gas that makes it fuzzy and makes the pH less the 7. In chemical terms you could say the cola is an aqueous solution where water is the __ sugar is a __ and carbon dioxide makes the solution __

A

Solvent
Solute
Acidic

57
Q

Radioisotopes can be used in medical studies because __

A

Their location or quantity can be determined because of their radioactivity

58
Q

True or false

Table salt, water, and carbon are compounds

A

False

59
Q

True or false

The smallest unit of an element is a molecule

A

False

60
Q

True or false

A bathtub full of lukewarm water may hold more heat then a teakettle full of boiling water

A

True

61
Q

True or false

If the atoms in a molecule share electrons equally the molecule is said to be non polar

A

True

62
Q

True or false

Ice floats because water molecules in ice are more tightly packed then in liquid water

A

False

63
Q

True or false

Atoms in a water molecule are held together by the sharing of electrons

A

True

64
Q

True or false

Most acid precipitation results from the presence of pollutants from aerosol cans and air conditioners

A

False

65
Q

True or false

An atom that has gained or lost electrons is called an ion

A

True

66
Q

Define organic compounds

A

Carbon based molecules

67
Q

What is one of the simplest organic molecules

A

Methane

68
Q

Define hydrocarbons

What are two examples

A

Compounds composed of only carbon and hydrogen

Methane and propane

69
Q

Define carbon skeleton

A

The chain of carbon atoms in an organic molecule

70
Q

Define isomers

A

Compounds with the same formula but different structural arrangements

Biology 1000 (11 decks)

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