Sci 150 – Chemistry Answers

Flashcard maker : Marie Florence
discovered by Becquerel in late 1800s
“phosphoresscence” experiment
3 types of nuclear radiation
alpha radiation
high energy helium nuclei
least penetrable (paper, foil can block it)
beta radiation
high energy electrons
dense wood and heavy clothing can block it
gamma radiation
high energy electromagnetic radiation
most dangerous
thick lead walls, concrete can block it
2nd leading cause of lung cancer in US
alpha emitter
nuclear fission
breaking apart
stable ratios in nucleus
if isotope has too many neutrons, not stable-likely to decay
otto han bombarded Uranium 92 with neutrons and got Ba 56
he sent his data to lise mietner who coined the term nuclear fission
produces huge amounts of energy and 3 extra neutrons
chain reactions
in order for it to occur, had to have a critical mass (must be purified)
neutrons hit atoms and produce more neutrons
manhattan project
US plan to build the first atomic weapon
production facilities in washington and oak ridge tn
oak ridge was where the separation of U-235 from U-238 occurred
first atomic bombs
little boy-assembled in Los Alamos, NM
fat man
both types need an initiator (neutron source)
first and only military use
exploded above Hiroshima and Nagasaki on Aug 6 and 9 1945
complete devastation for a 2 mile radius
unfortunately the technology is fairly simple
the hydrogen bomb
fusion- several smaller atoms come together releasing energy
in the sun, 4 hydrogen atoms fuse to make helium + positrons + electrons
in the bomb, deuterium + tritium fuse at high temperatures
other use for fission
nuclear power
provides ~15% of world’s electricity
80% in france
30% in Japan
20% in US
problems with nuclear energy
terrorist threats
waste disposal- Yucca mountain
environmental disasters- 3 mile island, Chernobyl, Fukushima
somatic damage- radiation burns
genetic damage- radiation affects womens’ eggs
carbon-14 dating
carbon 14 reacts to form 14 CO2
becomes incorporated into living objects while they are alive
by measuring ratios of C isotopes, can tell age of species
shroud of turin- jesus’ burial cloth?
radiation in medicine
I-131 used to treat thyroid disorders and cancer
Cobalt-60 used to treat cancer
PET scan
carbon chemistry
in everything alive
valence structure C (4 dots around)
likes to make 4 bonds
hydrocarbon- hydrogen and carbon
families of hydrocarbons
alkanes-single bond
alkenes- double bond
alkynes- triple bond
same chemical formula, different structure
naming: identify longest carbon chain
have at least one double bond, 4 electrons shared
have at least one triple bond, share 6 electrons
contain a ring structure, all single bonds
most smell good
contain benzene- c6h6 extremely stable
something consumed to produce energy
gas, food, wood, coal etc.
petra- rock, oleum- oil
mixture of hydrocarbons and other organic compounds
must be separated into components to be useful
fractional distillation-fractions separated based on their volatility
how your car works
make chemical energy into kinetic energy
4 strokes in an engine
intake, compression, power, exhaust
high compression ratio- more fuel efficient
ignition doesn’t fire consistently
likelihood increases with increased compression ratio
may need gasoline with a higher octane rating
octane rating
measure of a gasoline’s resistence to knocking
2,2,4 trimethylpentane-if used in car it won’t knock
heptane knocks readily
most common blends are 87,89,93
leaded gasoline
cheap way to improve octane rating
poisons environment
also poisoned catalytic converters
MTBE methyl tert-butyll ether
used as octane enhancer and an oxygenate
pollutes water supply
being replaced with ethanol
avogadros number
# of atoms in exactly 12g of carbon-12
6.02 x 10^23
how much solute is dissolved in given amount of solvent
homogeneous mixure
does the dissolving
is being dissolved
moles of solute/L of solution
part per million
mg of solute per L of solution
part per billion
micrograms of solute per L of solution
taste sour, turn litmus red, react with certain metals to release H30+
taste bitter, turn litmus blue, feel slippery, release OH in solution
acids and bases can react together to form a salt (and frequently water)
compound produced by a neutralization reaction
Arrhenius (what he said about acids and bases)
acid produces H+ (proton or hydronium) in water
base produces OH-(hydroxide ion) in water
an acid can transfer a proton to another species
a base can accept a proton from another species
water-acid or base?
dynamic equilibrium
concentrations are fixed, reactions always occurring but you can’t measure it
they occur both ways
pure water and solutions
at any given point in time, there are free H3O+ and free OH- in pure water
as long as their concentrations are equal, we say that the water is neutral
strong acids
ionize completely in water
ex. sulfuric acid-H2SO4, hydrochloric acid-HCl, nitirc acid-HNO3
weak acids
partially ionize in water
ex. citric acid, acetic acid
strong bases
ionize completely in water
ex. NaOH, KOH
weak bases
partially ionize in water
ex. NaHCO3, NH3
power of hydronium ion
-log [H30+]
pH of acidic solution
less than 7
pH of neutal solution
pH of basic solution
greater than 7
[H30+] x [OH-} = 1×10^-14
need it in our diet
we get most from fruits and veggies
B vitamin
helps reduce risk of vascular disease
prevents neural tube defects in developing fetuses
folic acid
colorless liquid
found as an ester in butter and some cheeses
formed from sugars by bacteria
rancid unpleasant odor
locker room smell
butyric acid
most important in pro-vitamin A family
occurs naturally, usually with chlorophyll
yellow coloring agents for foods
found in carrots
good for eyes
originally derived from plants
1700s- 2nd only to rice as cash crop
can now be synthesixed from napthalene
used to color original star spangled banner
used to color blue jeans
highly soluble in lipids
prescription drug to alleviate sever pain
used as a treatment for narcotic withdrawl
used in detoxifying opiate addicts
becoming more frequently abused
approved by FDA in 1998
similar to sucrose
made by chlorinating sucrose
no nutritional vlaue
mixed with maltodextrin and sold as splenda
naturally occurring phytoalexin
found in grapes, soybeans and peanuts
may function as an anti-oxidant
may prevent cancer, heart disease, and extend your life
may be responsible for the french paradox
an oil mixture
found in plants
R group dependent on species
can cause contact dermatitus
soluble in water
heavy skunk odor
used as additive in natural gas
tert-butyl mercaptan
hormone/ chemical transmiter
released by mast cells
can cause gastric acid secretion, breathing difficulty, itchy watery eyes
1 carbon- CH4
2 carbons- C2H6
3 carbons- C3H8
4 carbons- C4H10
5 carbons- C5H12
6 carbons- C6H14
7 carbons- C7H16
8 carbons- C8H18
9 carbons- C9H20
9 carbons- C9H20
10 carbons- C10H22

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