Unit 1- Intro to Chem Flashcards
scientific method
investigations that are guided by theory and earlier experiments
hypothesis
possible explanation for an event
law
a statement that sums a large # of observations
theory
an explanation of the laws of nature
matter
anything that has mass and takes up space
mass
quantity of matter in an obj
weight
the force of attraction between 2 obj
property
anything observed or measured about a sample of matter
extensive property
depends on SIZE of sample (mass, volume)
intensive property
indep of sample size
(density, color, melting point, boiling point)
physical property
can be measured W/OUT changing the composition of the sample (mass, density, color, melting point)
physical change
a change that occurs w/out changing the composition of the material
chem property
describes the reactivity of a material (ex: methane burns in air)
chem change
at least part of the materials changed into a diff kind of matter (ex: burning methane produces CO2 and H2O)
substances
a material that is chemically the same throughout
elements
cannot be broken into smaller substances by chemical means
compounds
can be broken into simpler substances
mixture
matter that can be separated into simpler materials by PHYSICAL METHODS
heterogenous mixtures
composition of the mix changes from one part to another (ex: rock)
homogenous mixtures (solutions)
composition of the mix is uniform throughout (ex: air)
alloys
solutions of metal and another material (usually other metal)
accuracy
the agreement of a set of measurements with the TRUE VALUE (darts close to center/ same distance from center)
precision
agreement among repeated measurements of the SAME QUALITY (darts close to one another)
sig fig
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)
uncertainty in sig fig
addition/subtraction: # with least DECIMAL places is least certain
multiplication/division: # with least SIG FIG is least certain
rounding methods
- less than 5, round down
- 5, round to EVEN
- more than 5, round up
SI system: length
meter (m)
SI system: mass
kilogram (kg)
SI system: time
second (s)
SI system: temp
kelvin (K)
SI system: amount
mole (mol)
SI system: electric current
ampere (A)
SI system: Luminous Intensity
candela (cd)
SI prefix: mega-
(M) 10^6
SI prefix: kilo-
(K) 10^3
SI prefix: centi-
(c) 10^-2
SI prefix: milli-
(M) 10^-3
SI prefix: micro-
(fancy u)10^-6
SI prefix: nano-
(n) 10^-9
SI prefix: pico-
(p) 10^-12
unit conversion factors
a fraction in which the numerator quantity is a quantity equal or equivalent to the quantity in the denom, but expressed in DIFFERENT UNITS
Non SI units: 1L =
1000mL or 1000 cm^3 (1mL = 1cm^3)
density
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)
T(f)=
T(c) x (1.8(f)/1(c)) +32(f)
T(c)=
(T(f) - 32(f)) x (1(c)/1.8(f))
T(k)=
T(c) + 273.15
