exam 1

Question 1

chemistry

Answer 1

science that studies matter and its changes

Question 2

science

Answer 2

a body of knowledge based on experimentation and careful reasoning

Question 3

the scientific method

Answer 3

a systematic method of acquiring new knowledge based on observation experimentation and careful reasoning

Question 4

hypothesis

Answer 4

testable explanation of the facts that can be proved wrong

Question 5

scientific law

Answer 5

statements of natural phenomena to which there are no known exceptions.

Question 6

scientific hyposthesis

Answer 6

a testable explanation of the facts

Question 7

Scientific theory

Answer 7

a well tested hyposthesis

Question 8

matter

Answer 8

anything that takes up space

Question 9

examples of things that are not matter

Answer 9

light
sound
energy

Question 10

intermolecular forces

Answer 10

forces among molecules tend to pull particles together

-depends on structure of molecules

Question 11

solid crystal

Answer 11

• intermolecular forces are strong
• particles are organized in a fixed position/they touch
• particles vibrate
• very low compressibility/expansibility
• definite shape/volume
• rigid

Question 12

solid amorphus (regular solid)

Answer 12

• intermolecular forces are strong
• particles touch
• particles vibrate
• very low compressibulity/expansibility
• definite shape/volume
• rigid

Question 13

liquid

Answer 13

• intermolecular forces are weak
• particles touch/slide
• particles move in translations/vibrations
• very low compressibulity/expansibility
• indefinite shape/definite volume
• fluid

Question 14

gas

Answer 14

• intermolecular forces are negligible
• particles are far away from each other/random
• particles motion: translation,vibration,rotations
• very high compressibulity/expansibility
• indefinite shape/volume
• fluid

Question 15

how to classify matter

Answer 15

pure substances and mixtures

Question 16

elements

Answer 16

• is a pure substance
• in the periodic table
• metals.nonmetals,metalloids

Question 17

compounds

Answer 17

• two or more elements chemically combined creating something new
• has a fixed composition
• ionic and molecular
• can be separated by chemical means

Question 18

mixtures

Answer 18

• two or more substances physically combined, not making anything new
• variable composition
• can be separated by physical means

Question 19

heterogeneous

Answer 19

different properties throughout

Question 20

homogeneous

Answer 20

is uniform in appearance and the same properties throughout

Question 21

what is an element?

Answer 21

pure substance made out of the same type of atoms

Question 22

how many known elements are there?

how many occur in nature/

Answer 22

• 118

- 4 of the first 92

Question 23

how many elements are unstable

Answer 23

all elements beyond 92 except for plutonium(94)

Question 24

how are elements arranged?

Answer 24

• by increasing atomic number
• periods:rows
• groups:columns
• lanthanoids and actinoids (center of periodic table)

Question 25

groups

Answer 25

-elements in the same group have similar properties -Group 1A: Alkali metals Group 2A: Alkaline earths Groups 3A: Boron Group 4A: Carbon Group 5A: Nitrogen Group 6A: Chalcogen Group 7A: Halogen Group 8A: Noble Gases

Question 26

Properties of metals

Answer 26

- all solid(except mercury) - shiny(lustrous) - malleable - ductil - good conductor of electricity/heat

Question 27

Properties of nonmetals

Answer 27

- solid(except bromine) - gases(group8A, nitrogen, hydrogen, oxygen,fluorine,chlorine) - nonlustrous - nonmalleable - nonductil - poor conductor of electricity/heat

Question 28

properties of metalloids

Answer 28

have properties of both metals and nonmetals

Question 29

molecules

Answer 29

composed of: nonmetals/nonmetals physical state of matter:solid, liquid,gas conduct electricity: don't conduct electricity

Question 30

ions

Answer 30

composed of: metals/nonmetals physical state of matter: solid conduct electricity:conducts electricity in solution and molten

Question 31

chemical properties

Answer 31

the substance ability to react and form new substances

Question 32

physical change

Answer 32

doesnt produce new substances

Question 33

chemical change

Answer 33

produces new substances

Question 34

sublimination

Answer 34

going from solid to gas

Question 35

deposition

Answer 35

going from gas to solid

Question 36

vaporization

Answer 36

liquid to gas

Question 37

condensation

Answer 37

gas to liquid

Question 38

law of conservation of mass

Answer 38

the total mass of the reactants = total mass of the products

Question 39

energy

Answer 39

the ability to do work; move an object against an opposing force

Question 40

potential energy

Answer 40

stored energy due to its position or composition or matter

Question 41

kinetic energy

Answer 41

energy of motion KE= 1/2mv^2 m=mass,v=velocity{distance(m^2/times^2)}

Question 42

law of conservation of energy

Answer 42

energy can not be destroyed or created, only transformed

Question 43

energy units

Answer 43

1cal=4.184 joules 1kilojoule= 1000J 1KCAL=1000cal

Question 44

specific heat

Answer 44

amount of heat required to increase the temperature by one degree

Question 45

energy in chemical changes

Answer 45

chemical changes can produce energy and energy can be used during a chemical reaction

Question 46

exothermic reaction

Answer 46

produce/release energy(hot) - low to high - negative values/loses energy

Question 47

endothermic reaction

Answer 47

absorbs energy(cold) - high to low - positive values/absorbs energy