CHEM 210 Chapters 1-3
Experiment
Procedure to test hypothesis; measures one variable at a time
Model (Theory)
Set of conceptual assumptions that explains data from accumulated experiments; predicts related phenomena
Chemical formula
denotes the composition of the substance
Extensive Property
depends on the amount of matter
Qualitative
descriptive with no explicit measurements
Homonuclear
diatomic molecules, both atoms in each molecule are of the same element
Heteronuclear
diatomic molecules, containing atoms of different elements
Intensive Property
does not depend on the amount of matter
A substance can be further categorized as
element or compound
Mixtures are either
homogeneous or heterogeneous
Exact Numbers
include numbers with defined values
Hepta
7
Octa
8
Nona
9
Molecular formula
shows the exact number of atoms of each element in a molecule
The three physical states a substance can exist
solid, liquid and gas
Condensed Phases
solids and liquids
Atomic Weight
sometimes used to mean average atomic mass
Chemists classify matter as?
substance or mixture
Accuracy
tells us how close a measurement is to the true value
Precision
tells us how close multiple measurements of the same thing are to one another
Element in the same group?
tend to have similar physical and chemical properties
Millikan discovered
the charge of the electron
J.J. Thomson Discovered
the charge-to-mass ration of the electron
heterogeneous mixture
the composition is not uniform
homogeneous mixture
the composition of the mixture is uniform throughout
Atomic Mass
the mass of an atom in atomic mass units (amu)
Significant Figured
the meaningful digits in a reported number
Atomic Number (Z)
the number of protons in the nucleus of each atom of an element
Chemical Change
the original substance will no longer exist
Protons
the positively charged particles in the nucleus
Density
the ratio of mass to volume
Hydrocarbons
the simplest organic compounds are those that contain only carbon and hydrogen
Chemistry
the study of matter and the changes that matter undergoes
Mass Number (A)
the total number of neutrons and protons present in the nucleus of an atom of an element
Dimensional Analysis (Factor-Label Method)
the use of conversion factors in problem solving
Nonmetal
usually a poor conductor of heat and electricity
Celsius to Fahrenheit
(9 degrees Fahrenheit/5 degrees Celsius) x (temperature in Celsius) + 32 degrees Fahrenheit
Giga
1 x 10^9
Mono
1
Deci
1 x 10^-1
Pico
1 x 10^-12
Centi
1 x 10^-2
Milli
1 x 10^-3
Micro
1 x 10^-6
Nano
1 x 10^-9
Tera
1 x 10^12
Kilo
1 x 10^3
Mega
1 x 10^6
Deca
10
Di
2
Tri
3
Tetra
4
Penta
5
Hexa
6
Matter
Anything that has a mass and occupies space
Periods
Horizontal Rows on the Periodic Table
Celsius to Kelvin
K = Degrees Celsius + 273.15
Mass
Measurement of the amount of matter in an object or sample
Observations
Natural phenomena and measured events; if universally consistent, can be stated as a law
Fahrenheit to Celsius
Temperature in Celsius = (temperature in Fahrenheit - 32 degrees Fahrenheit) x (5 degrees Celsius/9 degrees Fahrenheit)
Hypothesis
Tentative explanation that explains observations
Further Experiment
Tests predictions based on model
Groups or Families
Vertical Columns on the Periodic Table
Molecule
a combination of at least two atoms in a specific arrangement held together by electrostatic forces known as covalent chemical bonds
Mixture
a combination of two or more substances in which the substances retain their distinct identities
Substance
a form of matter that has definite (constant) composition and distinct properties
Conversion Factor
a fraction in which the same quantity is expressed one way in the numerator and another way in the denominator
atomic mass unit (amu)
a mass exactly equal to one-twelfth the mass of one carbon-12 atom
Compound
a substance composed of atoms of two or more elements chemically united in fixed proportions
Element
a substance that cannot be separated into simpler substances by chemical means
Acid
a substance that produces hydrogen ions (H+) when dissolves in water
Measurement of electric current
ampere (A)
Nucleus
an extremely dense central core within the atom
A compound cannot be separated into simpler substances by
any physical process
Why did Chadwick name them neutrons?
because they were electronically neutral particles having a mass slightly greater than that of protons
How are substances identified?
by their properties as well as by their composition
Measurement of luminous intensity
candela (cd)
Organic Compounds
contain carbon and hydrogen, sometimes in combination with other elements such as oxygen, nitrogen, sulfur and the halogens
Diatomic Molecule
contains two atoms
What are the two types of numbers used in Chemistry?
exact and inexact
Fluids
gases and liquids
Metal
good conductor of heat and electricity
Metalloid
has properties that are intermediate between those of metals and nonmetals
Kelvin
is known as the absolute temperature scale, meaning that the lowest temperature possible is 0K; absolute zero
Allotrope
is one of two or more distinct forms of an element
Measurement of temperature
kelvin (K)
Measurement of mass
kilogram (kg)
Quantitative
measured and expressed with a number
Inexact Numbers
measured by any method other than counting
Elements can be categorized as?
metals, nonmentals or metalloids
Measurement of length
meter (m)
The derived SI united for volume
meter cubed (m^3)
Measurement of an amount of substance
mole (mol)
Binary
molecular compounds that consist of just two different elements
physical change
one in which the state of matter changes, but the identity of the matter does not change
physical property
one that can be observed and measured without changing the identity of a substance
Chemical property
one that in order to observe this we must carry out a chemical change
Measurement of time
second (s)
Structural formula
shows not only the elemental composition, but also the general arrangement of atoms within the molecule
