131 terms

# Introduction to Chemistry & Physics Midterm Exam Review

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Science
the process of discovering and explaining the order of things
Scientific Method
helps put investigation of questions into some type of order, formal/organized method for doing science
Hypothesis
a reasonable explanation of an observation, an educated guess
Who was punished by the church for their scientific belief?
Galileo
Do facts change in science?
Yes, in science facts change when new info is discovered
Scientific Theory
the synthesis of info that contains well tested and verified hypothesis about certain aspects of the world
Quantitative Measurements
- more easily backed up
- measuring data using #s give more proof to your answer
What happens if a scientist is dishonest with their data or fats?
Shunned by scientific community
Pseudoscience
ex: astrology
false science
Quantitative
denotes a quantity or how much is observed
Qualitative
denotes quality of what is observed
Inference
statement reasoned from an observation
Independent variables
changes that occur in an experiment that are directly caused by the experimenter
Dependent variables
changes that occur due to an independent variables
Controlled variable
anything else that could influence the dependent variable
1cm^3 =
1mL
length:
meter
mass:
gram
volume:
liter
1000 millimeters =
1 meter
100 centimeters =
1 meter
100 meters =
1 kilometer
Control setup
identical experiment without the variable to be tested; the original state of item to be experimented upon
Research
information gathered to support your hypothesis
Conclusion
the ending solution that has been found
Variable setup
setup that includes the factor to be tested
Problem
what you are trying to find out by preforming the experiment
Volume (Solid obj)
water level with solid added
- original water level
Giga
G
10^9
billion
Mega
M
10^6
million
Kilo
K
10^3 1,000
thousand
Centi
c
10^-2 .01
hundredth
Milli
m
10^-3 .001
thousandth
Micro
10^-6
millionth
Nano
n
10^-9
billionth
Density
mass per unit of volume of a substance
Density (formula)
Mass/Volume
Volume
mass/density
length x width x height
s^3
Mass
density x volume
chemistry
study of matter and the transformation it could undergo
matter
anything that has mass and occupies space
Basic research
understand how nature works
Applied research
dedicated to the development of useful products ad processes
The submicroscopic world is made up of
atoms and molecules
Submicroscopic means
cannot be seen with a microscope
(this includes atoms and molecules)
Molecules are made up of
atoms that makeup the fundamental unit of a material
Chemical change/reaction
atoms in a substance are rearranged to give a new substance having a new chemical identity
Chemical equation
representation of a chemical reaction
Chemical formula
symbols for the different elements and the ratio of each element
Chemical properties
a property that relates to how a substance changes its chemical identity
Compound
a material in which atoms of different elements are bonded to one another
Chemistry
study of matter and the transformations it can undergo
Elemental formula
atomic symbol and a numerical subscript to indicate the numer of atoms grouped together
Laws of Mass Conservation
matter is neither created nor destroyed during a chemical reaction
Matter
anything that occupies space
Molecules
group of atoms that collectively make the fundamental unit of a material (i.e. water)
Physical Change (definition)
a change in which a substance changes its physical properties without changing its chemical identity
Physical Properties
any physical attribute of a substance, such as color, density, or hardness
Products
a new material formed in a chemical reaction, appearing after the arrow in a chemical equation
Reactants
a starting material in a chemical equation, appearing after the arrow in a chemical equation
Physical properties (examples)
color, hardness, density, phase(form of a substance), etc.
Chemical properties
Characteristics that can only be observed when one substance changes into a different substance.
What happens to the atoms during a chemical change?
the atoms rearrange to form a new material different from the starting material
Chemical bond
attraction between two atoms that hold them together
Phases of matter:
solid - definitine shape and volume
gas - no definite shape or volume
liquid - no definite shape, but definite volume
plasma (high energy) - can't be contained
freezing, melting, vaporization, condensation, sublimation
Element
collection of atoms
(one type of atom)
Elements combine to form
compounds
Compound:
more than one type of atom
Atomic Mass
the mass of an element's atom listed in the periodic table as an average value based on the relative abundance of the element's isotope
Atomic Nucleus
the dense, (+) charged center of every atom
Atomic Number
a count of the number of protons in the atomic nucleus
Atomic Symbol
an abbreviation for an element or atom
Electron
an extremely small, (-) charged subatomic particle found outside the atomic nucleus
Element
a fundamental material consisting of only one type of atom
Group
a vertical column in the periodic table, also known as a family of elements
Isotopes
atoms of the same element whose nuclei contain the same number of protons but different numbers of neutrons
Mass Number
the number of nucleons (protons and neutrons) in the atomic nucleus. Used primarily to identify isotopes.
Metal
an element that is shiny, opaque, malleable, and able to conduct electricity and heat
Metalloid
an element that exhibits some properties of metals and some properties of nonmetals
Neutron
an electrically neutral subatomic particle of the atomic nucleus
Non-metal
neither a metal nor a metalloid, poor conductor of electricity and heat, may be transparent, not malleable or ductile
Nucleon
any subatomic particle found in the atomic nucleus (another name for protons and neutrons)
Period
a horizontal row in the periodic table
Periodic Table
a chart in which all known elements are organized by their properties
Periodic Trend
a chart in which all known elements are organized by their properties
Proton
a (+) charged subatomic particle of the atomic nucleus
Elements are organized in their periodic table by
their properties
Metals (electrons & location)
give up electrons
left side of periodic table
Nonmetals (electrons & location)
take electrons
right side of periodic table
valance electrons
any electron in the outer most energy level or shell of an atom
A period is a
row
A group is a
column
Which groups tell us how many valance electrons are in the group?
1, 2, 13, 14, 15, 16, 17, 18
group 1
alkali metals
group 2
alkaline earth metals
group 17
halogens
When a metal combines with a halogen, what is formed?
The compound, salt
group 18
noble gases
Atoms get smaller moving from
left to right across any row or period
Atoms get larger moving
down a group because of an increase in occupied shells
Ionization energy
amount of energy required to pull an electron away from an atom
Which elements have the highest and lowest ionization energies?
highest: upper right
lowest: lower left
Protons =
Atomic #
Electrons =
number of protons
Neutrons =
Mass # - Protons
Atomic # =
# of protons
Mass # =
protons + neutrons
physical model
represents a large or small object shown at a convenient scale
conceptual model
represents a systems and helps use to predict how it behaves (i.e. Niels Bohr's planetary mode)
spectroscope
instrument used to observe the color components of any light source
atomic spectrum
the pattern of frequencies formed by a given element
What did Bohr reason about the orbits?
Bohr reasoned that orbit have different energy levels and that if an electron moves from one energy level to another it emits photons (particle of light).
Explain Bohr's planetary model?
it was a conceptual model
the electrons traveled around the nucleus in definite orbits (like the planets orbiting the sun)
What did the Bohr model predict?
X-ray frequencies that were later confirmed by experiment
Quantum hypothesis
light travels as a wave, but strikes a a particle
Photon
a particle of light
Quantum
the smallest unit of something
Principal quantum number n
an integer (#) that specifies the quantized energy level of an atomic orbital
shells
region of space where electrons may reside
Probability cloud (cloud model of the atom)
where the electrons may be found
Uncertainty principle (cloud model of the atom)
the electrons
The simplest type of purse substance
element
Each periodin the table begins on the left with a
highly active metal
Elements found on the left sight of periodic table are
metals
Elements that exist in nature as two atoms covalently bonded are called
diatomic
Elements in the same group have similar
properties
Quantum mechanics
behavior of submicroscopic particles
synthesis reaction
a reaction in which two or more substances combine to form a new compound
decomposition reaction
(chemistry) separation of a substance into two or more substances that may differ from each other and from the original substance
double replacement reaction
when two compound reactants switch places in the product
catalyst
substance that speeds up the rate of a chemical reaction