Chem Unit 1 Thing Flashcards by Gail I

scientists have discovered all of the matter in our universe is made up of … different types of chemical elements. about … of these occur naturally

116; 90

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all the elements that make up the universe derived from the

big bang

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our universe began at a single point that was thousands of times smaller than the head of a pin. it was also … and more .. than any object we know of today. this heat still remains as …

hotter; dense; cosmic background radiation

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… billion years ago, in the flash of the big bang, high energy … collided with each other, forming … Typically, when this happened the oppositely charged … and … annihilated each other instantly, converting back into …

14; photons; oppositely charged particles; matter; antimatter; high energy photons

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in the first seconds of the universe, for reasons scientists cannot explain, it is estimated that … particle of … for approximately every … of … were not annihilated

one; matter; one billion particles; antimatter

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as the universe expanded, both the plasma and the radiation filling it grew colder. when the universe cooled and stable atoms could form, they eventually could no longer absorb the … and the universe became … instead of being an opaque … The photons that from that time have been propagating ever since, growing fainter and less energetic

thermal radiation; transparent; fog

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.. minutes after the big bang, the universe began to cool down from 10^32 degrees C to 10^9 degrees C and … and … began to …

protons; neutrons; combine

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about 300,000 yrs later, the universe had cooled enough for positively charged protons to attract the … and the first … formed

negatively charged electrons; atoms

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during the formation of the universe only atoms of the lightest elements-…, …, … and … were formed.
As the cloud of cosmic dust and gases from the Big Bang cooled, … formed, and these then grouped together to form … and … The high … and … within stars caused protons and neutrons to fuse together. In smaller stars like our sun, the temperatures are 15.5 million degrees C at the core, hot enough to make He and H only

H; He; Li; Beryllium; stars; galaxies; stars; pressure; temperature

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in the core of hotter, larger giant stars:
… fuse to make helium
… fuse to make atoms with … protons-beryllium
… and … fuse to make atoms with … protons- carbon
… and … fuse to make atoms with … protons-oxygen, etc. and in this manner elements with up to … protons formed

hydrogens; heliums; 4; helium; beryllium; 6; carbon; helium; 8; 12

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atoms of elements … to … formed in … stars

aluminum; iron; Super Giant

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the most massive elements from … to … were created in … called …

iron; uranium; star explosions; supernovae

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in the late 1800s scientists were passing electricity through glass tubes containing a very small amount of … like oxygen. when the power was turned on, the tube emitted light and glowed. the positive electrode is called the … and the negative called the … They called the rays … because they appeared to be coming from the … end of the tube

gas; anode; cathode; cathode rays; negative

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there was much speculation about what these cathode rays were. when an object was placed in the path of the rays, the rays cast … of the objects placed in their path.
… casts a shadow-so it could be light
or it could be a stream of tiny particles

shadows; light waves

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scientists found that they could … this beam by subjecting it to an additional …

deflect; electrical field

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the beam deflected toward the positive charge because it carried a … meaning that the rays were …

negative charge; particles

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scientists found that they could also deflect this beam by subjecting it to a …
right arm rule: in the magnetic field above a … would deflect up
this also indicates that the rays were …

magnetic field; negative charge; particles

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since the particles were easily deflected, they must have either a really small … or a really large …

mass; charge

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J.J. Thomson and team determined that the charge to mass ratio is: … C/kg
all gases experimented on had the same charge to mass ratio

1.76 x 10^11

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physicists proposed these negatively charged particles be called …. they have the same charge to mass ratio as the negative particles generated by …, …, and … materials

electrons; static electricity; heated materials; illuminated

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A scientists named Millikan squirted oil drops into a box and then passed high energy … at the box hoping to knock electrons off the air molecules and onto the oil drops. By measuring the energy necessary to stop the drops from descending, he was able to determine the … The more energy needed to prevent the drop from falling, the … the charge of the drops

x-rays; charge per drop; smaller

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after the discovery of the electron, scientists believed that there must also be a … in the atom. to look for these, they used an … tube. by placing holes in the cathode so particles could move through it, they found that particles were indeed moving from the … to the … since they move towards a … plate, they must be …

positively charged particle; anode ray; anode; cathode; negative; positive

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the anode rays were referred to as .., which were found to be significantly heavier than electrons.
1 proton = … x mass of electron

protons; 1840

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since the heaviest anode rays in oxygen were found to be 8 x heavier than those in hydrogen, it was assumed that oxygen had 8 protons compared ot hydrogen’s 1
the … an atom has is different for each element on the periodic table

number of protons

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once it was determined that atoms are made up of negatively and positively charged particles, J.J Thompson and team proposed that the structure of an atom resembled … the model featured a … sphere of matter with … embedded in it. this was based around the idea that … and .. charges attract and … charges repel

plum pudding; positive; negative electrons; positive; negative; like

ernest Rutherford used .. to test the plum pudding theory

radioactivity

radioactivity is the spontaneous emission of … by an atom. Rutherford studied emissions from the unstable element uranium. larger elements like uranium contain an atomic nucleus that can be either … and does not change, or radioactive, meaning that it …, or …, into another relement after a certain amount of time. decay can be as short as a fraction of a second and as long as a few million years radioactive decay: nucleus breaking into … and ...

stable; transforms; decays; smaller nuclei; releasing energy

three types of radiation were discovered by Ernest Rutherford: a-rays: … particles (… charged particles with a mass roughly ..x that of the proton) b-rays- … particles (…) y-rays- … rays (form of … with very high ..)

alpha particles; positively; 4; beta; electrons; gamma; light; energy

physicists Geiger and marsden under the direction of ernest Rutherford shot a beam of … at a thin sheet of .. and observed the scatter pattern of the particles

alpha particles; gold foil

in the plum pudding model of the atom, positive and negative charges are dispersed evenly throughout the atom. if this model were correct, the high energy alpha particles would be slightly … by … as they passed through the foil. Rutherford and team expected all alpha particles to … the atoms in the gold foil and be deflected by only a few degrees

deflected; weak electric fields; pass through

most of the particles flew right through the foil with no deflection at all, but some … meaning that the protons are … together in the center of the atom

bounced back; clustered

the only way to account for the large angles was to assume that all the positive charge was contained within a … a small very dense … must lie within a mostly empty atom. now we know that the radius of the nucleus is … that of the atom

tiny volume; nucleus; 1/10000

since electrons were so much smaller than protons, Rutherford believed the mass of an atom would be simply related to the number of … present but the atoms were much heavier than predicted

protons

Rutherford guessed it came from another particle called a .. and verified its existence

neutron

neutrons have a mass that is essentially the same as a … and … charge. the mass of a proton or neutron is described an ...

proton; no; atomic mass unit

since electrons have a much smaller mass than a proton or neutron, the mass of an atom (in u) is generally considered to be equal to the sum of the … and … in an atom

protons; neutrons

Rutherford postulated a very small, dense nucleus containing protons and neutrons with the electrons around the outside of the atom. most of the volume of the atom is

empty space

protons and neutrons together are referred to as …, the amount of which is called the .. and is designated by the letter ...

nucleons; mass number; A;

neutron number is .. and atomic number is

N; Z

atoms of the same element can have different numbrs of --> ...

neutrons; isotopes

not all isotopes are found in the same … in nature

abundances

the atomic mass indicates the … of all … of a given element. this is the number reported on the periodic table

average atomic mass; isotopes

for elephants a higher N-15 to N-14 in their hair occurs in … climates, a lower ratio occurs in .. climates

dry; wet

fission: ... (... achieved in lab) Fusion: ... (... achieved in lab)

separating; was; combining; was not

similarities between fission and fusion: ... changes ... and .. large amounts of ...

radioactivity; Z; A; energy

protons and neutrons continued to collide and were held together by the ..., creating a more massive version of hydrogen called ..., ..., and trace amounts of ... and ...

Strong Nuclear Force; Deuterium; Helium; Tritium; Lithium

When two deuterium atoms fuse together to form a helium atom, the mass of the helium atom is ... than that of the two original atoms

less

the missing mass, delta m (...), is converted to ... as predicted by Einstein's famous formula, .... This released energy is called the ...

mass defect; energy; E = delta m * c^2; binding energy

The energy of nuclear fusion powers .... | It works to make increasingly heavy ....; the source of most atoms heavier than ... and ..., up to ...

stars; atoms; hydrogen; helium; iron

Elements heavier than iron are formed when ..., in massive ... As we'll see, those heavier nuclei also release ..., when they divide through ..... Energy is released whenever a nucleus gets closer to being ..., the most ... nucleus

stars explode; supernova explosions; energy; fission Iron; stable

fusion hold great promise as being a virtually ... form of ... for use on Earth. However, so far, people have only been able to unleash this energy in an ... form, as a "..."

unlimited; energy; explosive; Hydrogen Bomb

while nuclear fusion reactions release energy while .... more massive elements, nuclear fission releases energy by ... very massive elements the heavy nucleus splits into ... when a nucleus heavier than iron divides into parts, the mass of the resulting nuclei is ... than the original. Again, ... is released

generating; dividing; lighter nuclei; less; binding energy

the energy release in a fission reaction is quite large. the smaller nuclei are stable with ... neutrons, so ... emerge from each fission. The neutrons can be used to ... in surrounding nuclei, causing a ... ... built the first self sustaining ... in Chicago in 1942

fewer; multiple neutrons; induce fission; chain reaction; Enrico Fermi; nuclear reaction

fission was first used to create an uncontrolled release of energy: the ... later, the release of energy via fission was controlled so as to create a peceful use for energy in ... ... or ... is the "fuel" that powers these nuclear power plants

atomic bomb; nuclear power plants; uranium; plutonium

fission occurs in the ..., which ... in a primary loop, which ... in the secondary loop. then, you just have a regular .../... generator which generates ...

reactor vessel; heats water; boils water; steam/turbine; electricity

heavy, unstable nuclei can also become stable by emitting .... the remaining nucleus is ... and more ... This is called ... and was first observed and studied by Henri Becquerel, Marie Curie and Pierre Curie

radiation; lighter; stable; radioactivity

there are three types of radiation: ... particles: ... nuclei (... neutrons and ... protons) ... particles: ... ....- high energy ...

helium; two; two; beta; electrons; gamma rays; electromagnetic radiation

radioactivity occurs all the time and is one of the sources of ... within Earth. Heavy nuclei emit ... on an ongoing basis as they move towards becoming ... and more ... we are all subject to ...f rome arth

heat; radiation; lighter; stable nuclei; background radiation

alpha particles are stopped by ... beta particles are stopped by a ... gamma rays are the most ... and are stopped by ...

sheet of paper; thin sheet of aluminum; penetrating; several meters of lead

a macroscopic sample of any radioactive substance consists of a greater number of ..., which do not decay ... The decay is ... and the decay of one nucleus has ... with the decay of any other nuclei

nuclei; at one time; random; nothing to do with

the number of decays during any time period depends on the ... after each specific time period, ... of the nuclei decay. This specific time period is called the isotope's ... the isotopes of a specific element have very different half-lies; ranging from millionths of seconds to the age of the universe

number of nuclei; half; half-life