unit 1+2 test

Question 1

mixture

Answer 1

mix of substances that have a variable composition; is classified as homogeneous or heterogeneous

Question 2

relative formula mass

Answer 2

the ratio of the average mass per atom of the naturally occurring form of an element to one-twelfth the mass of an atom of carbon-12

Question 3

empirical formula

Answer 3

chemical formula which gives the lowest whole number ratio of the atoms or moles of the element in a compound

Question 4

molecular/covalent compound

Answer 4

compounds of elements made from a non metal + non metal

Question 5

mole

Answer 5

aka Avogadro’s number; 6.02x10^23; unit of measurement for the amount of a chemical substance

Question 6

physical property

Answer 6

something you can see/observe without a chemical change happening: ex. luster, color, volume, state, density, melting point, boiling point, shape, malleability

Question 7

chemical change

Answer 7

bonds are broken and new bonds are formed; chemical composition changes: ex. color/odor, emission, heat, precipitate, light

Question 8

periodicity

Answer 8

recurring variations in element properties with increasing atomic number

Question 9

compound

Answer 9

substance composed of a given combination of elements that can be broken down into those elements by chemical methods; elements are always combined in the same proportions

Question 10

group

Answer 10

vertical columns share similar properties bc they are organized by valence electrons

Question 11

electron

Answer 11

negatively charged particles

Question 12

significant figure

Answer 12

each of the digits of a number that are used to express it to the required degree of accuracy

Question 13

molar mass

Answer 13

mass of one mole of a given substance

Question 14

alkali metals

Answer 14

low-density, low-melting, highly reactive metallic elements

Question 15

atom

Answer 15

smallest particle that makes up element

Question 16

product

Answer 16

substance that is formed as the result of a chemical reaction

Question 17

matter

Answer 17

stuff that has mass and takes up space; 3 states: solid, liquid, gas

Question 18

scientific notation

Answer 18

method of expressing numbers in terms of a decimal number between 1 and 10 multiplied by a power of 10

Question 19

properties of metals

Answer 19

good conductors of heat/electricity, shiny, solid at room temperature, ductile/malleable

Question 20

law of conservation of mass

Answer 20

mass is neither created nor destroyed by chemical reactions or physical transformations; themassof the products in a chemical reaction must equal themassof the reactants

Question 21

element

Answer 21

substance that can’t be broken down into other substances by chemical methods; each is unique

Question 22

percent composition

Answer 22

percentage by mass of each element in a compound

Question 23

reactant

Answer 23

a substance that takes part in and undergoes change during a reaction

Question 24

molecular formula

Answer 24

equal to or whole number multiple of empirical formula

Question 25

heterogenous

Answer 25

different

Question 26

isotope

Answer 26

atoms of the same element has the same number of protons but different numbers of neutrons

Question 27

periodic table

Answer 27

organized by atomic number

Question 28

chemical property

Answer 28

something you can see only if substance is undergoing reaction: ex. acidity, reactivity, flammability

Question 29

alkaline earth metals

Answer 29

react easily with other elements and are found in nature only in compounds

Question 30

chemical equation

Answer 30

symbolic representation of a chemical reaction

Question 31

ionic compound

Answer 31

compounds of elements made from a non metal + metal

Question 32

distillation

Answer 32

transition of a substance directly from the solid to the gas phase without being a liquid

Question 33

ion

Answer 33

a charged atom or group of atoms

Question 34

abundance

Answer 34

amount of an isotope of an element that exists in nature

Question 35

transition metals

Answer 35

Any of the metallic elements within Groups 3 through 12 in the Periodic Table; form alloys easily, have high melting points, and have more than one valence because of their incomplete inner shells

Question 36

atomic number

Answer 36

number of protons an element has

Question 37

physical change

Answer 37

chemical composition remains; change of one or more properties: ex. state change, color, density, volume

Question 38

nucelus

Answer 38

holds protons and neutrons; electrons “orbit” around the outside

Question 39

properties of nonmetals

Answer 39

poor conductors of heat and electricity, most are gases at room temperature, brittle, not metallic

Question 40

pure substance

Answer 40

substances made of only one type of atom

Question 41

halogens

Answer 41

nonmetallic; react readily with most metals to form salts

Question 42

atom

Answer 42

smallest particle of an element that retains it’s identity

Question 43

states of matter

Answer 43

different forms matter takes on; solid, liquid, gas, plasma

Question 44

period

Answer 44

a set of elements occupying a row in the periodic table 9

Question 45

proton

Answer 45

positively charged particles

Question 46

noble gases

Answer 46

do not react chemically with other substances except under certain special conditions

Question 47

homogeneous

Answer 47

the same

Question 48

average atomic mass

Answer 48

average mass of one atom of a particular element

Question 49

nucleon

Answer 49

a proton or neutron

Question 50

neutron

Answer 50

neutrally charged particles

Question 51

mass number

Answer 51

number of protons and neutrons an element has

Question 52

polyatomic ion

Answer 52

charged ion composed of two or more atoms covalently bonded together