chapter 1: introduction to chemistry Flashcards
chemistry: study of matter and its interactions with
other matter and with energy
foundation of chemistry is
experimentation
chemistry is an experimental science in which we derive knowledge from
carefully planned and performed experiments
to formulate ideas for experiments, scientists draw on
experience, using experimental data and theory
hypothesis is a possible
explanation for an event
law: a statement that can summarize
a large number of observations
theory: an explanation of
the laws of nature
theories are subject to change when
new data becomes available
matter: anything with
mass and volume
mass: amount of
matter in an object
weight: force of …. between a particular object and ….
attraction; another object
weight is also the measure of the
gravitational pull on an object
balance to measure
mass
scale to measure
weight
property: observations or
measurements regarding matter
physical properties: properties that can be measured without
changing the composition of the sample
examples of physical properties:
mass, volume, color, phase
chemical properties: describe
reactivity of a material
examples of chemical properties:
explosiveness, flammability, lack of reactivity
physical change: does not change the
composition/ identity of a substance
examples of physical change
freezing, melting, boiling
chemical change: involves the transformation of matter into
different substances
examples of chemical change
rusting, burning
extensive properties: depend on the
size of the sample
extensive properties measure how much … is in a particular sample
matter
examples of extensive properties:
mass, volume
intensive properties: not dependent on the
size of the sample
intensive properties depend on
what the sample is
examples of intensive properties:
colors, melting points, densities
intensive properties can be used to
identify a substance
substance: chemically the
same throughout
element: cannot be broken down into
simpler, stable substances
compound: can be
broken down into simpler, stable substance
matter can be classified by:
chemical composition, physical state, color, etc.
compounds are uniform in
composition and properties throughout
mixture: matter that can be separated into two or more substances by differences in the
physical properties of the components
homogenous mixture:
uniform in composition
examples of homogenous mixtures:
sugar-water solution, air
heterogenous mixtures:
not uniform in composition
examples of heterogenous mixtures:
mixture of iron and sand, vegetable soup, salt and pepper
samples of the same mixture can have different …, unlike …
compositions; substances
alloy: a solid solution that consists of a
metal and another substance, usually another metal
substance: matter that cannot be separated into
component parts by a physical process
compounds: substances that can be decomposed into simpler substances or into their elements by
chemical processes
compounds always contain the same elements in the
same proportions
all samples of a compound have the same
intensive properties
symbols for the elements are abbreviations for their
names
numerical measurements have 4 aspects:
object, value; units; reliability
reliability:
accuracy and precision
accuracy: expresses how close a measurement is to the
correct or accepted value
precision: refers to the closeness of a set of measurements to
each other, but not necessarily the accepted value
accurate: number has a small
error
precise: number has small
uncertainty
significant figures: used to display the
uncertainty of results
significant figures: all digits known with certainty, plus one more digit that is
not certain
uncertainty of final digit is
± 1
nonzero digits are
significant
zeros between nonzero digits are
significant
with no decimal point to the right of a zero, the trailing zero may or may not be
significant (clarified by scientific notation)
if there is a decimal point, leading zeros are …, but zeros at the end of the number are …
insignificant; significant
number of sig figs in a calculated value results from the… of the …and the …that were used to attain the final value
uncertainties; measurements; operations
addition/subtraction sig figs: answer has the same number of decimal places as the component with the
least number of decimal places
multiplication/division sig figs: answer has the same number of sig figs as the component with the
least number of significant digits
(rounding rules) if digit after the last sig fig is
round down
(rounding rules) if digit after the last sig fig = 5,
round to even
(rounding rules) if digit after the last sig fig is > 5
round up
density: ratio of
mass to volume
three kinds of numbers never limit sig fits:
counted numbers/tallies, defined numbers, power of ten
quantities: describe… and illustrate …
properties; precise information
units: standards by which
measurements are compared
SI units: 7 base units which define
length, mass, time, temperature, amount of substance, electrical current, luminous intensity
length:
meter
mass:
kilogram
time:
second
temperature
kelvin
amount of substance:
mole
electrical current:
ampere
luminous intensity:
candela
base units can be
reproduced in labs (exception: kilogram)
derived units: physical quantities that can be expressed as a
combination of base units
when multiplying by conversion factors, the … are what change, along with the ….
units; numeric value
(prefixes) yotta- Y
10^24
(prefixes) zeta- Z
10^21
(prefixes) exa- E
10^18
(prefixes) peta- P
10^15
(prefixes) tera-T
10^12
(prefixes) giga-G
10^9
(prefixes) mega- M
10^6
(prefixes) kilo- k
10^3
(prefixes) hecto- h
10^2
(prefixes) deka- da
10^1
(prefixes) deci- d
10^-1
(prefixes) centi- c
10^-2
(prefixes) milli- m
10^-33
(prefixes) micro- µ
10^-6
(prefixes) nano- n
10^-9
(prefixes) pico- p
10^-12
(prefixes) femto- f
10^-15
(prefixes) atto- a
10^-18
(prefixes) zepto- z
10^-21
(prefixes) yocto- y
10^-24
unit conversion factor: fraction in which the numerator is a quantity that is equal or equivalent to the quantity in
the denominator but expressed in different units
to know what conversion factor should be used, determine which units should be … and which units you are attempting to …
canceled; attain
standard unit for volume is
m^3
density is a … property that can help
physical; identify substances
density can’t be used to convert between
different substances
standard unit for density:
kg/ m^3
none of the relationships between the English and SI units is …; effects …
exact; sig figs
conversion factors between Celsius and Fahrenheit
TF = TC x (1.8℉/1.0℃) + 32 ℉ TC = (TF - 32 ℉) x (1.0℃/1.8℉)
absolute zero:
-273.15 degrees C
conversion between Celsius and kelvin:
Tk = Tc + 273.15
