Unit 2

Question 1

matter

Answer 1

anything that takes up space and has mass

Question 2

element

Answer 2

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

Question 3

compound

Answer 3

a substance consists of 2 or more types elements, Ex H20

Question 4

trace elements

Answer 4

elements found in small quantities

Question 5

neutrons and protons form

Answer 5

atomic nucleus

Question 6

electrons form

Answer 6

a ring around the nucleus

Question 7

daltons

Answer 7

the atomic mass unit

Question 8

atomic number

Answer 8

the number of protons in its nucleus

Question 9

mass number

Answer 9

the sum of protons + the neutrons in the nucleus

Question 10

isotopes

Answer 10

2 atomic forms of an element that differs in number of neutrons

Question 11

radioactive isotopes

Answer 11

Decays spontaneously and lose subatomic particles, give off particles and energy

Question 12

energy

Answer 12

the capacity to cause change

Question 13

potential energy

Answer 13

the energy that matter has b/c of the location or structure

Question 14

reactivity of an atom…

Answer 14

derives from the presence of 1+ more unpaired electrons in the valence shell

Question 15

inert (unreactive) atoms

Answer 15

atoms with completed valence shells

Question 16

covalent bond

Answer 16

the sharing of a pair of valence electrons by 2 atoms. One of the strongest bonds.

Question 17

molecule

Answer 17

2+ atoms held together by covalent bond

Question 18

bonding capacity

Answer 18

the number of electrons required to complete the atom

Question 19

pure elements

Answer 19

molecules composed of 1 type of atom, Ex: H2

Question 20

electronegativity

Answer 20

an atom’s attraction for the electrons of a covalent bond. The more electronegative, the more stronger the electrons pull toward itself.

Question 21

nonpolar covalent bond

Answer 21

the atoms share the electrons equally

Question 22

polar covalent bond

Answer 22

1 atom is electronegative and the atoms don’t share them equally

Question 23

ion

Answer 23

2 oppositely charged atoms or molecules

Question 24

ionic bond

Answer 24

attraction between an anion(neg) and a cation(pos). Ionic compounds formed by these bonds.

Question 25

hydrogen bond

Answer 25

a hydrogen atom covalent bonded to 1 electronegative atom, also attracted to another electronegative atom. Weak chemical bond.

Question 26

Van der Waals interactions

Answer 26

this occurs when atoms and molecules are very close together

Question 27

cohesive force

Answer 27

forces between molecules, this keeps the substance together

Question 28

adhesive force

Answer 28

forces that attract 1 substance to another

Question 29

surface tension

Answer 29

a measure of how hard it is to break the surface of a liquid. related to cohesion.

Question 30

kinetic energy

Answer 30

the energy of motion

Question 31

thermal energy

Answer 31

a measure of the total amount of kinetic energy

Question 32

temperature

Answer 32

the avg kinetic energy of molecules

Question 33

heat

Answer 33

the thermal energy in transfer from 1 body of matter to another

Question 34

calorie

Answer 34

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

Question 35

kilocalories

Answer 35

1cal=1000 cal

Question 36

joule

Answer 36

a unit of energy 1 J= 0.239 cal 1 cal=4.184 J

Question 37

specific heat

Answer 37

the amount of heat that must be absorbed or lost for 1g of that substance to change its temp by 1C

Question 38

water has high specific heat...

Answer 38

keeps temp fluctuations within limits that permits life

Question 39

heat of vaporization

Answer 39

the heat a liquid must absorb for 1g to be converted to gas

Question 40

evaporative cooling

Answer 40

the liquid evaporates and its surface remains cool

Question 41

solution

Answer 41

a liquid that is a homogenous mixture of substances

Question 42

solvent

Answer 42

the dissolving agent of a solution

Question 43

solute

Answer 43

the substance that is dissolved

Question 44

aqueous solution

Answer 44

the water is the solvent

Question 45

hydration shell

Answer 45

an ion surrounded by a sphere of water molecules

Question 46

molecular mass

Answer 46

the sum of all masses of all atoms in a molecule

Question 47

molarity

Answer 47

the number of moles of solute per liter of solution

Question 48

acid

Answer 48

increases the H+ concentration in water

Question 49

base

Answer 49

reduces the concentration of H+

Question 50

pH

Answer 50

-log[H+]

Question 51

buffers

Answer 51

substances that minimizes changes in concentrations of H+ and OH- solution. Usually contains weak acid and its base.

Question 52

carbonic acid

Answer 52

a buffer that contributes to pH stability in human blood

Question 53

ocean acidification

Answer 53

CO2 dissolved in seawater that forms carbonic acid