CHEMISTRY 110

Which Science is primarily concerned with the study of matter and the changes it undergoes?
Chemistry

Natural Philosophy
theoretical speculatuon about nature

DDT- insecticide during WWII
Carsonian nightmare

Science is
tentative, explanatory, testable, predictive, reproducible

Proposing butadiene in glue will make it stickier is an example of a(n)
hypothesis

Results in an experiment are easier to interpret when the experiment has how many variables?
One

Synthesizing a medical remedy for cancer is an example of what kind of research?
Applied Research

Does the weight of a person change when there are gravitational differences?
YES

Does the mass of a person change do to gravitational differences ?
NO

A compound that conducts electricity when molten or dissolve in water
Electrolyte

Carbon rods or metallic strips that carry electrical current
Electrodes

Anode
a positive electrode

Cathode
a negative electrode

Ion
an atom or group of atoms with a charge

Anion
a negative ion

Cation
A positive ion

Leucippus and Democritus
Discovered that atoms cannot be subdivided and molecules are atoms chemically bonded together

Lavoisier
Law of Conservation Mass: matter can neither be created nor destroyed
*X=Z

Proust
Law of Definite Proportions: compound always contains the same element in definite propoetions

Berzelius
Experiment to illustrate Law of Definite Proportions: Lead Sulfide

John Dalton
Law of multiple proportions: Different atoms can combine with different ratios

Isotopes
atoms of same element (atomic number)with different masses (atomic weight)

Mendeleev
arranged elements in order of increasing atomic mass

J.J. Thomson
discovered electrons — cathode anode tube

Roentgen
used cathode ray tube– discovered xrays (electromagnetic radiation)

Becquerel
discovered radioactivity

Marie and Pierre Curie
worked to isolate pure radioactive substances

Types of Radioactivity
Alpha: Positive
Beta: Negative
Gamma: Neutral

Rutherford
gold foil experiment: discovered nucleus

Atomic #
the number of protons and electrons in the nucleus

Atomic Weight #
Sum of protons and neutrons in the nucleus

Same # of protons and electrons, different number of neutrons
Isotopes

Elements give different color flames
Flame Test

Light from gas substances pass through prism to produce a line– result from electrons returning to lower levels
Line Spectrum

When energy from a flame or source is absorved by the electrons and promoted to a higher energy state
Excited State

Ground State
when electrons are in the lowest stare of energy

When a tiny unit of energy is produced or absorved when an electron makes a transition from one energy level to another
Quantum

When an electron in an excited state returns to a lower energy state, it emits ___ of energy which may be observed as light
Photon

Goldstein
observed positive rays using perforated cathode

Millikan
Determined Charge of electrons by oil-drop experiment *calculated the absolute mass of an electron

Another name for Energy levels
Shells

The Quantum Model
probability-based

What is the Quantim Model composed of?
principle energy levels,sublevels, and orbitals(1,2,3,4,5..)

Principle Energy Levels (shells)
roughly correlate to the distance that an electron is from an atom’s nucleus

Sublevels(subshells)
each principle energy level (n) is divided into {s,p,d,f}

Orbitals
regions in space that represent a high probability of locating an electron
{(s-1),(p-3),(d-5),(f-7),}

Electron Configuration
represents the arrangement of the electrons in an atom

What is the periodic table composed of?
Groups(families): vertical columns containing similar chemical properties
Periods: horizontal rows range of metallic to nonmetallic

Valence Electrons
-in the outermost principle energy level of an atom
-gained lost or shared in chemical reactions
-elements in a group or family have the same amount

What’s the major distinction b/w Greek Philosophers and Modern Scientists?
Experimentation

Scientific Results must be Verified by?
Further Experiment

Example of Basic Research
Otto Stern and Walther Gerlach’s discovery that atomic nuclei have spins

Mass is a better measure of the amound of matter than weight is because
Mass is Independent of location

Sodium reacts with water to form sodium hydroxide, this is an example of ?
Chemical Property

Chemical Change always involves a change in the ___ of a piece of matter?
Composition

Characteristics of Gas
Indefinite shape, indefinite volume

Substance that cannot be broken down by chemical means into simpler substances is called?
an Element

Centi-
100

Kilo-
1000

Density
m/v

Freezing point for Celsius
0 degrees

The energy content in food is in Calories, Calorie is equal to__?
1000 calories

If 1 Calorie is equal to 1000 calories, how many Joules are there?
4.184 Joules

Leucippua and Democritua propoaed the “first” atomic vire of matter based on?
philosophical and intuitive speculation

Methane can be decomposed into simpler substaces, therefore?
it cannot be an element

the atomic masses for elements in the periodic table are ?
relative masses determined by comparison with a standard reference

a stream of electrons will behave in what way in an electrical field?
be deflected toward the positive electrode

the spontaneous emission of radiation from unstable elements
radioactivity

which type od radioactivity is NOT deflected by a magnetic field?
Gamma

The nuclear model of the atom waa constructed from which fundamental experiment?
Alpha particles scattering by thin metal foils

Relative to the mass of the nucleus of an atom, the mass of the electron is?
always much smaller

the identity of an element is determined by what?
the number of protons in the atom

The MAX number of elextrons in the n=4 energy level is?
32

What is the max number of electrons that can occupy the 3p sublevel?
6

Elements in the same group have?
the same number of valence electrons

The inertness of the noble gases is due to?
the number and arrangement of their electrons

When atoms lose or gain electrons in chemical reactions they form
Ions

With reapect to chemical bonding, which particles play the most active role?
Valence Electrons

the attraction between positive and negatice ions is known as an
ionic bond

When sodium loses a valence electron its core electrons are configured like which noble gas?
Neon

Chlorine can gain an electron and its electron structure becomes like?
Argon

Octet Rule
In chemical reactions atoms tend to gain, lose or share electrons so as to have eight valence electrons.

Metals lose electrons to take on the electron structure of the previous noble gas. They form__?
Cations

Nonmetals tend to gain electrons to take on the electron structuee of the next noble gas. They form__?
Anions

Covalent Bond
sharing of electrons

Polyatomic ions
groups of covalently bonded atoms with a charge

How many rules are there for sketching Lewis Structures?
5

Rule #1
Count Valence Electrons

Rule #2
Sketch a skeletal structure

Rule #3
Place electrons as lone pairs around outwe atoms to fulfill the octet rule

Rule #4
Subtract the electrons used so far from the total number of valence electrons. Place any remaining electrons around the central atom.

Rule #5
If the central atom lacks an octet, move one or more lone pairs from an outer atom to a double or triple bond to complete an octet

Free Radicals
an atom or molecule with an unpaired electron

The Valence Shell Electron Pair Repulsion (VSEPR)
theory predicts the shape of molecules and polyatomic ions based on repulsions of electron pairs on central atoms

What must happen in order for a molecule to be polar?
1. it must have polar bonds
2. the bonds must be arranged such that a separation of charge exists