chem unit 3

Question 1

physical properties

Answer 1

qualities/characteristics that can be observed without changing chemicals make-up

Question 2

Extensive

Answer 2

dependant on the amount of substance

Question 3

intensive

Answer 3

independent on the amount

Question 4

chemical properties

Answer 4

the ability to react with/form substance

Question 5

physical changes

Answer 5

that alter a substance without changing its make-up
Ex: ripping paper

Question 6

chemical changes

Answer 6

the process by which substance are in
Ex: burning

Question 7

evidence of a chemical change

Answer 7

1) change in color
2)formation of a gas
3) bubbles and odor
4) change in temp

Question 8

states of matter

Answer 8

solid, liquid, gas, plasma (sometimes)

Question 9

Solid

Answer 9

• structure in rigid and closed-pack
• particles are fixed in place
  -volume and shape are fixed

Question 10

liquid

Answer 10

• particles in contact, bu not fixed positions
• flow, move
  -define volume, but not definite shape. (takes shape of container)

Question 11

Gas

Answer 11

• particles move freely
  -lots of energy
  -no fixed volume or shape
  -expands to fill the container
  -takes the shape of the container

Question 12

Law of conservation of mass

Answer 12

matter is neither created nor destroyed in (ordinary) chemical or physical changes

Question 13

General Equation

Answer 13

M reactants = M products

Question 14

Law of definite proportions

Answer 14

a compound is always composed of the same element in the same proportion by mass

Question 15

percent by mass equation

Answer 15

percent by mass= M element/ M compound X 100%

Question 16

Law of multiple proportions

Answer 16

when different compounds are formed by the combination of the same element different masses of an other element in ratio of small whole numbers

Question 17

mixtures

Answer 17

two or more substances are combined, but each pure substance retains its individual properties.

Question 18

heterogeneous mixtures

Answer 18

Do not blend smoothly (does not mix together)

Question 19

homogeneous mixtures

Answer 19

(also called solutions) have a single visible phase (mixes togther)

Question 20

Filtration

Answer 20

used to separate mixtures of liquids (filtrate) and solids. Uses porous barrier (filter) to separate a solid from a liquid
EX: sand and water mixtures

Question 21

Distillation

Answer 21

used to obtain a pure liquid from a mixture
Based on difference in boiling points- lowest boiling point liquid vaporize and vapor is collected
EX: purifying water

Question 22

Crystallization

Answer 22

used to separate dissolved solids from a liquid in solutions
pure solid particles crystallized from saturated solutions
often the best way to obtain a pure solid
EX: rock candy

Question 23

Chromatography

Answer 23

used to separate components of mixtures containing gases and/or liquids
Based on the ability of each component to travel or be drawn across a stationary phase
EX: ink on paper in water

Question 24

sublimation

Answer 24

used to separate a substance that sublimates from one that does not Solid/ solid mixture
not widely used because few substance sublimates
EX: iodine and another solid

Question 25

mechanical

Answer 25

used for heterogeneous mixtures