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Chemistry Test One

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3 states of matter
liquid, gas, solid
entahalpy
heat
enthropy
degree of disorder
2 atoms together are??
more stable than two atoms apart
gas distribution of speed is?
related to temperature
liquid near the surface means?
evaporation
If particles are at a cooler temperature, what happens?
The travel at a lesser speed and the molecules condense
mater
anything that occupies space, exhibits inertia, has resistance to change in motion, and has mass
mass
measure of the amount of matter
atom
smallest unit of an element that maintains the properties of that element
element
a pure substance made of only one kind of atom
molecule
smallest possible unit of an element or compound that retains all of the properties of that element or compound
in molecules some atoms?
exist together with 2 or 3 atoms together
extensive property
depends on the amount of matter (e.g.) weight or mass, volume, energy
Intensive property
doesn't depend on the amount of matter (e.g) melting point, boiling point, density, vapor, pressure, electrical conductivity,
physical property
a characteristic which can be tested without changing the basic make up of what you have (folding, tearing, chopping, stacking, sorting, cutting, or change of state -- water vaporizing)
8 examples of physical changes
1)boiling point 2)melting point 3)volume 4)purity 5)mass 6)length 7)temperature 8)density
chemical change
when new chemicals are made (e.g) breaking of old bonds and rearranging of new bonds)
chemical
any substance that has a definite composition
compound
two or more atoms bonded together chemically
exothermic
reaction that releases heat
precipitate
mixing 2 solutions together and solid stuff is the product
solution
a mixture of things which are the same all the way through that can be solid (brass) liquid (kool-aid) or gas (air) they are all mixtures
what are the seven steps of the scientific method?
1. make observation 2. organize 3. make hypothesis 4. do experiments 5. did hypothesis work 6. develop a theory 7. do more experiments
3 parts of scientific measurement
1. numbers 2. estimate of uncertainty 3. units
What is a unit of measurement?
It is a physical quantity of a defined size that scientists agree on
The worldwide standard made of platinum, alloy and iridium is used for which worldwide measurment
the kilogram
what are the seven fundamental SI units
length mass time electric current temperature amount of substance luminous intensity
length is measured in??
meters
mass is measured?
kilograms
time is measure?
seconds
electric currents is measured?
ampere
temperature is measured?
kelvin
amount of substance is measured?
moles
luminous intensity is measured?
candela (cd)
What is a derived SI unit?
This is an SI unit that can be obtained from combinations of fundamental units (eg) volume L x W x H = v cubed
What are the three parts of a problem?
1. information given and measurements 2. Understand the question 3. Connection of 1 and 3... tolls needed to get from 1 to 2
accuracy
how closely the measured values agree with the true or accepted value
precision
how closely measurements agree
atoms are?
the building block of matter
What did the Greeks have to do with the beginning in developing the idea of the atom?
The greeks presented the atom to the world, and made the first model which was a dot
What was the major breakthrough in the 1790's?
the balance which measure mass
What is the law of conservation?
mass is neither destroyed or created during ordinary chemical reactions or physical changes
Law of Definite Proportions
A chemical compound contains the same elements in exactly the same proportions by mass regardless of the size or sample
Law of Multiple Proportions
when two elements form a series of compounds the ratio of the masses of the second element that combine with one gram of the first element can always be reduced to small whole numbers
John Dalton did what?
explained conservation of mass and definite composition multiple proportions
Who developed the atomic theory?
John Dalton
What does the atomic theory state?
1. all matter is made of tiny particles called atoms 2. Atoms of a given element are identical; atoms of different elements are different in some fundamental way or ways 3. atoms can't be subdivided created or destroyed 4.atoms of different elements combine in simple whole number rations to form chemical compounds 5. chemical reactions involve reorganization, seperation or rearrangement of atoms -- how they are bound together
Who discovered the electron?
J.J Thompson
What was J.J Thompson's 'big discovery'?
The cathode ray tube
Along with discovering the electron, what else did J.J Thompson experiment with?
electrical discharge (cathode rays) in partially evacuated tubed called Cathode Ray Tubes (CRTs)
What was Thompson's 'discovery' of electrons based on?
the studies of cathode rays
How are cathode rays produced?
The are produced when gas is ionized
What were Thompson's observations?
1. Cathode rays are deflected by a magnetic field 2. Cathode rays are charged 3. Cathode rays are deflected from a negative electrode 4. Cathode rays must be negative 5. Electrons can be produced from all kinds of metals 6. all atoms must contain electrons 7. There must be a positive and negative charge
From Thompson's experiment which model of the atom was developed?
The Plum Pudding model
What is the SI unit of charge?
Columb (C)
What is a Columb?
It is defined as the amount of charge that flows past a fixed point in a wire per cecond when the current is one ampere
From the Cathode Ray what could Thompson determine?
the mass to charge ratio (kg/C)
What is Robert Millikan famous for?
The oil drop experiment
Who is famous for the oil drop experiment?
Robert Millikan
What did Millikan discover through his oil drop experiment?
He determined the charge of an electron and measured the mass of an electron
How did Millikan make his discovery?
Hye used thompson's charge to mass ratio
What did Millikan use?
He used an oil atomizer, 2 charged plates, looked through a microscope and had an x-ray
Millikan experimented with?
electrically charged oil drops
by varying the electrical field, what did Millikan observe?
That the oil drops had charges of whole numbers
The drop of oil represented what?
The charge of the electron
How was the mass determined?
By using the calculations of the mass to charge ratio and the charge
Which experiment made Ernest Rutherford famous for?
the experiment using alpha particles, a piece of gold foil, and a circular instrument
How did the alpha particles react to the gold in Rutherford's experiment?
Most of the alpha particles went through the foil, but some bounced off and hit zinc
Which part of the atom did Rutherford discover?
The nucleus
What is a nuclear atom?
The nucleaus is positively charged It is dense in the middle Mostly made of mass and has very little volume atoms are mostly made of space
What does the nucleus consist of?
Protons and neutrons and contains most of the mass
What takes up most of the volume in an atom?
The electrons
How are atoms counted?
by mass
What is the standard for the basing of atomic mass?
Carbon- 12
Elements exist as a ???
distribution of naturally occurring isoptopes, regardless of the location
What is the average atomic mass?
the weighted average of the atomic masses of the naturally occurring isotope of an element
What does the avgerage atomic mass unit represent?
the amounts of mass that reacts in chemical reactions
What is a mole?
the measurement of the amount of substance.
What is Avagadro's Number?
It is the number of particles in exactly one mole of a pure substance
What is molar mass?
it is the mass in grams of one mole of a pure substance
nucleons
collective name for protons and neutrons in a nucleus
What defines an element?
the atomic number
mass defect
this is the difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons
nuclear binding energy is?
the energy released when a nucleus is formed from neutrons and protons (nucleus)
What about the nuclear binding energy per nucleon?
the binding energy of the nucleus divided by the number of nucleons it contains
What number of protons must an element contain so that is always unstable
84 or more
Define Isotope
same number of protons but with a different mass
What are the two classes of radioactive decay?
1. both the mass and atomic number change 2. mass number stays the same but the atomic number changes
what is radio decay?
the spontaneous breakdown of unstable nuclei to eventually stable ones
Is the nucleus positive or negative?
is positive because it contains the protons
when an alpha particle is emitted, what is really being emitted?
two protons and two neutrons from Helium
half-life
the time it takes for half the amount of radio active material to break down
What do neutrons give off to become protons
they give off beta particles
kinetics
how fast something happens
thermodynamics
the study if energy transfer during chemical reactions
decay series
a series of radioactive nuclides produced by successive radioactive decay steps until a stable nuclide is reached
nuclear family-- what makes up a parent nuclide?
the heaviest (original) nulcide of each decay series
What do parent nulcides produce
daughter nuclides
Artificial Transmutation
a nuclear transformation occurs when stable nuclei are bombarded with charged and uncharged particles
What is used to make an artificial transmutation happen?
cyclotrons and particles accels
fission
this is when a neutron hits the nucleus, which splits, giving off lots of energy, which makes smaller particles
fusion
combining two light nuclei to form a heavier more stable nucleus
What is a Roentgen?
unit of radation
what does nuclear radiation cause?
ionization
Rem
is the quanity of ionizing radiation that does as much damage to human tissue as is done by 1 roentgen of high voltage x-rays
What does radiation exposure cause?
cancer, mutations, but everyone gets radiation at least .1 to .5 per year
What are some ways to detect radiation?
film badge geiger counter scintillation counter
chain reaction
A chain reaction is a reaction in which the material that starts the reaction is also one of the products and can start another reaction
3 possible chain reaction scenarios?
sub-critical critical supercritical
Describe the criticals
sub critical- the reaction is stopped because there is nothing for the nucleus to run into to critical- contained and finds more neutrons to run into supercritical- neutron find uranium and continuously makes more
nuclear reactions
can make clean power but make a mess if the cooling water is shut off

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