Unit 2 (chapter 3)

Question 1

atom

Answer 1

the fundamental unit of which elements are composed

Question 2

chemical change

Answer 2

a change in the fundamental components of the substance
burning, rusting
new substances formed from original chemicals, usually difficult to reverse, energy is always given out or taken in resulting in temperature change, can result in color change due to new formation of products, new products can have a new state but don’t always

Question 3

chemical property

Answer 3

property that can only be observed after changing a substance’s identity
flammability

Question 4

decomposition

Answer 4

a chemical reaction in which one reactant breaks down into two or more products.

Question 5

distillation

Answer 5

separates liquid from a solution

Question 6

element

Answer 6

substance that cannot be decomposed into similar substances by chemical or physical means (consists of all atoms having the same atomic number)

Question 7

extensive property

Answer 7

depends on how much substance you have (mass, volume)

Question 8

filtration

Answer 8

separates insoluble solid from liquid

Question 9

formula unit

Answer 9

the lowest whole number-ratio of ions in an ionic compound

Question 10

heterogenous

Answer 10

visibly different or has visibly different parts

Question 11

homogenous

Answer 11

visibly same throughout at eye level (solutions)

Question 12

intensive property

Answer 12

does not depend on how much substance you have (color, density, melting point, solubility)

Question 13

law of conservation of matter

Answer 13

matter cannot be created nor destroyed in any physical change

Question 14

law of constant composition

Answer 14

a given compound always contains the same elements in the same proportion

Question 15

law of multiple proportions

Answer 15

the same elements can combine in different whole ratios to form more than 1 compound

Question 16

matter

Answer 16

anything that has mass and volume (density)

Question 17

mixture

Answer 17

has two or more types of particles
variable composition- varied amount of substance
not chemically joined
each substance in the mixture keeps to its own properties
easily separated
ex: air, seawater, most rocks

Question 18

molecule

Answer 18

group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction

Question 19

physical change

Answer 19

no new substances
usually easy to reverse
usually no significant energy change
usually no color change
substance usually changes state
no change in identity
size change
dissolving, cutting, bending, freezing, boiling, melting

Question 20

physical property

Answer 20

a property that can be measured or observed without changing a substance’s identity
color, melting point, solubility

Question 21

pure substance

Answer 21

only 1 type of particle, homogenous

Question 22

solute

Answer 22

is dissolved

Question 23

solution

Answer 23

homogenous mixture composed of two or more substances

Question 24

solvent

Answer 24

does the dissolving

Question 25

solid

Answer 25

particles are vibrating, touching, condensed. definite shape and volume

Question 26

liquid

Answer 26

particles are touching, condensed. definite volume (determined by number of particles, size). can move

Question 27

gas

Answer 27

particles are not touching, so far apart they have no impact on each other. constainer determines shape and volume (indefinite shape and volume).

Question 28

melting

Answer 28

solid to liquid

Question 29

freezing

Answer 29

liquid to solid

Question 30

sublimation

Answer 30

solid to gas

Question 31

deposition

Answer 31

gas to solid

Question 32

evaporation

Answer 32

liquid to gas

Question 33

condensation

Answer 33

gas to liquid

Question 34

pure substances- elements

Answer 34

cannot be broken down, made of atoms

Question 35

pure substances- compounds

Answer 35

can be broken down (decomposed), made of molecules or formula units

Question 36

liquid and solid separation

Answer 36

property: size, density, color
technique: filter, decanting

Question 37

liquid separation homo

Answer 37

property: boiling point
technique: distillation

Question 38

liquid separation hetero

Answer 38

property: density, lack of solubility
technique: decanting

Question 39

compound

Answer 39

definite composition- cannot vary
chemically joined
has properties that are different from the elements it contains
can be separated into elements using chemical reactions
ex: water, carbon dioxide, magnesium oxide, sodium chloride

Question 40

paper chromatography

Answer 40

separates mixtures of colored components
ex: inks, dyes, coloring agents in food
Rf=distance moved by compound/distance moved by solvent