Unit 1- Intro to Chem

Question 1

scientific method

Answer 1

investigations that are guided by theory and earlier experiments

Question 2

hypothesis

Answer 2

possible explanation for an event

Question 3

law

Answer 3

a statement that sums a large # of observations

Question 4

theory

Answer 4

an explanation of the laws of nature

Question 5

matter

Answer 5

anything that has mass and takes up space

Question 6

mass

Answer 6

quantity of matter in an obj

Question 7

weight

Answer 7

the force of attraction between 2 obj

Question 8

property

Answer 8

anything observed or measured about a sample of matter

Question 9

extensive property

Answer 9

depends on SIZE of sample (mass, volume)

Question 10

intensive property

Answer 10

indep of sample size
(density, color, melting point, boiling point)

Question 11

physical property

Answer 11

can be measured W/OUT changing the composition of the sample (mass, density, color, melting point)

Question 12

physical change

Answer 12

a change that occurs w/out changing the composition of the material

Question 13

chem property

Answer 13

describes the reactivity of a material (ex: methane burns in air)

Question 14

chem change

Answer 14

at least part of the materials changed into a diff kind of matter (ex: burning methane produces CO2 and H2O)

Question 15

substances

Answer 15

a material that is chemically the same throughout

Question 16

elements

Answer 16

cannot be broken into smaller substances by chemical means

Question 17

compounds

Answer 17

can be broken into simpler substances

Question 18

mixture

Answer 18

matter that can be separated into simpler materials by PHYSICAL METHODS

Question 19

heterogenous mixtures

Answer 19

composition of the mix changes from one part to another (ex: rock)

Question 20

homogenous mixtures (solutions)

Answer 20

composition of the mix is uniform throughout (ex: air)

Question 21

alloys

Answer 21

solutions of metal and another material (usually other metal)

Question 22

accuracy

Answer 22

the agreement of a set of measurements with the TRUE VALUE (darts close to center/ same distance from center)

Question 23

precision

Answer 23

agreement among repeated measurements of the SAME QUALITY (darts close to one another)

Question 24

sig fig

Answer 24

of digits form the first non-zero digit through last reported digit (trailing numbers w/out decimal may not be sign)
(doesnt include tallies, defined #s, and powers of ten in exponential notation)

Question 25

uncertainty in sig fig

Answer 25

addition/subtraction: # with least DECIMAL places is least certain
multiplication/division: # with least SIG FIG is least certain

Question 26

rounding methods

Answer 26

• less than 5, round down
• 5, round to EVEN
• more than 5, round up

Question 27

SI system: length

Answer 27

meter (m)

Question 28

SI system: mass

Answer 28

kilogram (kg)

Question 29

SI system: time

Answer 29

second (s)

Question 30

SI system: temp

Answer 30

kelvin (K)

Question 31

SI system: amount

Answer 31

mole (mol)

Question 32

SI system: electric current

Answer 32

ampere (A)

Question 33

SI system: Luminous Intensity

Answer 33

candela (cd)

Question 34

SI prefix: mega-

Answer 34

(M) 10^6

Question 35

SI prefix: kilo-

Answer 35

(K) 10^3

Question 36

SI prefix: centi-

Answer 36

(c) 10^-2

Question 37

SI prefix: milli-

Answer 37

(M) 10^-3

Question 38

SI prefix: micro-

Answer 38

(fancy u)10^-6

Question 39

SI prefix: nano-

Answer 39

(n) 10^-9

Question 40

SI prefix: pico-

Answer 40

(p) 10^-12

Question 41

unit conversion factors

Answer 41

a fraction in which the numerator quantity is a quantity equal or equivalent to the quantity in the denom, but expressed in DIFFERENT UNITS

Question 42

Non SI units: 1L =

Answer 42

1000mL or 1000 cm^3 (1mL = 1cm^3)

Question 43

density

Answer 43

a physical property of a substance calculated as the mass per unit volume
(d = m/v)
(SI units: kg/m^3)
(solids/liquids: g/cm^3 or g/mL)
(gases: g/L)

Question 44

T(f)=

Answer 44

T(c) x (1.8(f)/1(c)) +32(f)

Question 45

T(c)=

Answer 45

(T(f) - 32(f)) x (1(c)/1.8(f))

Question 46

T(k)=

Answer 46

T(c) + 273.15