Sci 150 – Chemistry Answers

question

radioactivity
answer

discovered by Becquerel in late 1800s
“phosphoresscence” experiment
question

3 types of nuclear radiation
answer

alpha
beta
gamma
question

alpha radiation
answer

high energy helium nuclei
least penetrable (paper, foil can block it)
question

beta radiation
answer

high energy electrons
dense wood and heavy clothing can block it
question

gamma radiation
answer

high energy electromagnetic radiation
most dangerous
thick lead walls, concrete can block it
question

radon
answer

2nd leading cause of lung cancer in US
alpha emitter
question

nuclear fission
answer

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
question

chain reactions
answer

in order for it to occur, had to have a critical mass (must be purified)
neutrons hit atoms and produce more neutrons
question

manhattan project
answer

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
question

first atomic bombs
answer

little boy-assembled in Los Alamos, NM
fat man
both types need an initiator (neutron source)
question

first and only military use
answer

exploded above Hiroshima and Nagasaki on Aug 6 and 9 1945
complete devastation for a 2 mile radius
unfortunately the technology is fairly simple
question

the hydrogen bomb
answer

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
question

other use for fission
answer

nuclear power
provides ~15% of world’s electricity
80% in france
30% in Japan
20% in US
question

problems with nuclear energy
answer

terrorist threats
waste disposal- Yucca mountain
environmental disasters- 3 mile island, Chernobyl, Fukushima
question

Chernobyl
answer

somatic damage- radiation burns
genetic damage- radiation affects womens’ eggs
question

carbon-14 dating
answer

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?
question

radiation in medicine
answer

I-131 used to treat thyroid disorders and cancer
Cobalt-60 used to treat cancer
PET scan
question

carbon chemistry
answer

in everything alive
valence structure C (4 dots around)
likes to make 4 bonds
hydrocarbon- hydrogen and carbon
question

families of hydrocarbons
answer

alkanes-single bond
alkenes- double bond
alkynes- triple bond
aromatics
question

isomerism
answer

same chemical formula, different structure
naming: identify longest carbon chain
question

alkenes
answer

have at least one double bond, 4 electrons shared
question

alkynes
answer

have at least one triple bond, share 6 electrons
question

cycloalkanes
answer

contain a ring structure, all single bonds
question

aromatics
answer

most smell good
contain benzene- c6h6 extremely stable
question

fuels
answer

something consumed to produce energy
gas, food, wood, coal etc.
question

petroleum
answer

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
question

how your car works
answer

make chemical energy into kinetic energy
question

4 strokes in an engine
answer

intake, compression, power, exhaust
question

diesels
answer

high compression ratio- more fuel efficient
question

knocking
answer

ignition doesn’t fire consistently
likelihood increases with increased compression ratio
may need gasoline with a higher octane rating
question

octane rating
answer

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
question

leaded gasoline
answer

cheap way to improve octane rating
poisons environment
also poisoned catalytic converters
question

MTBE methyl tert-butyll ether
answer

used as octane enhancer and an oxygenate
pollutes water supply
being replaced with ethanol
question

avogadros number
answer

# of atoms in exactly 12g of carbon-12
6.02 x 10^23
question

concentration
answer

how much solute is dissolved in given amount of solvent
question

solution
answer

homogeneous mixure
question

solvent
answer

does the dissolving
question

solute
answer

is being dissolved
question

molarity
answer

moles of solute/L of solution
question

part per million
answer

ppm
mg of solute per L of solution
question

part per billion
answer

ppb
micrograms of solute per L of solution
question

acids
answer

taste sour, turn litmus red, react with certain metals to release H30+
question

bases
answer

taste bitter, turn litmus blue, feel slippery, release OH in solution
question

neutralization
answer

acids and bases can react together to form a salt (and frequently water)
question

salt
answer

compound produced by a neutralization reaction
question

Arrhenius (what he said about acids and bases)
answer

acid produces H+ (proton or hydronium) in water
base produces OH-(hydroxide ion) in water
question

bronsted/lowry
answer

an acid can transfer a proton to another species
a base can accept a proton from another species
question

water-acid or base?
answer

both-amphoteric
question

dynamic equilibrium
answer

concentrations are fixed, reactions always occurring but you can’t measure it
they occur both ways
question

pure water and solutions
answer

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
question

strong acids
answer

ionize completely in water
ex. sulfuric acid-H2SO4, hydrochloric acid-HCl, nitirc acid-HNO3
question

weak acids
answer

partially ionize in water
ex. citric acid, acetic acid
question

strong bases
answer

ionize completely in water
ex. NaOH, KOH
question

weak bases
answer

partially ionize in water
ex. NaHCO3, NH3
question

pH
answer

power of hydronium ion
-log [H30+]
question

pH of acidic solution
answer

less than 7
question

pH of neutal solution
answer

7
question

pH of basic solution
answer

greater than 7
question

Kw
answer

[H30+] x [OH-} = 1×10^-14
question

MOLECULES OF THE DAY:
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
answer

folic acid
question

colorless liquid
found as an ester in butter and some cheeses
formed from sugars by bacteria
rancid unpleasant odor
locker room smell
answer

butyric acid
question

most important in pro-vitamin A family
occurs naturally, usually with chlorophyll
yellow coloring agents for foods
found in carrots
good for eyes
answer

beta-carotene
question

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
answer

indigo
question

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
answer

methadone
question

approved by FDA in 1998
similar to sucrose
made by chlorinating sucrose
no nutritional vlaue
mixed with maltodextrin and sold as splenda
answer

sucralose
question

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
answer

resveratrol
question

an oil mixture
found in plants
R group dependent on species
can cause contact dermatitus
answer

urushiol
question

soluble in water
heavy skunk odor
used as additive in natural gas
answer

tert-butyl mercaptan
question

hormone/ chemical transmiter
released by mast cells
can cause gastric acid secretion, breathing difficulty, itchy watery eyes
answer

histamine
question

ALKANES:
methane
answer

1 carbon- CH4
question

ethane
answer

2 carbons- C2H6
question

propane
answer

3 carbons- C3H8
question

butane
answer

4 carbons- C4H10
question

pentane
answer

5 carbons- C5H12
question

hexane
answer

6 carbons- C6H14
question

heptane
answer

7 carbons- C7H16
question

octane
answer

8 carbons- C8H18
question

nonane
answer

9 carbons- C9H20
question

nonane
answer

9 carbons- C9H20
question

decane
answer

10 carbons- C10H22

Get instant access to
all materials

Become a Member