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82 Cards in this Set
- Front
- Back
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what are the four principles of a fair test?
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1) controlling variables
2) eliminating bias 3) large sample size 4) using a control |
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what does controlling variables mean?
give an example in relation to the flame test. |
in an experiment you should only test one variable at a time, so keep all variables besides that one variable the same throughout all of the tests. it helps distinguish chance from real difference.
ex. keep the flame size the same, use the same kind of wooden sticks, have the same person compare the colors |
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what does eliminating bias mean?
give an example in relation to the flame test. |
it means that when evaluating or executing a test your choices aren't influenced by anything arbitrary. cover labels, don't tell people what they're testing, etc.
ex. cover all the labels of the chemicals, don't use people in the experiment that have done that activity before or know what colors or wavelengths they should be |
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what does having a large sample size mean?
give an example in relation to the flame test. |
it means testing a large group of samples so that one can have a more accurate/precise outcome. if there are any outliers they won't matter as much.
ex. do each chemical five times |
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what does using a control mean?
give an example in relation to the flame test. |
it means you have a control in which you eliminate that variable that you are testing the experiment for. it helps distinguish chance from real difference.
ex. burn a splint with nothing on it |
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draw an erlynmeyer flask.
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you drew a picture of a beaker with a skinny top, didn't you?
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what is the thing you use to light a bunsen burner?
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a sparker
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what the difference between:
a test tube clamp crucible tongs beaker tongs |
beaker tongs have plastic around the tong part, crucible tongs don't, and a test tube clamp has the squeeze mechanism instead of handles
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do you add acid to water or water to acid?
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add acid to water
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the definition of significant figures
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the number of digits in an experimentally derived measurement that gives significant information about the data quality
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whats the relation between sig figs and precision and accuracy?
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sig figs are more accurate and implied to be more precise
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when you measure something how many sig figs do you take?
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all of the ones you know from the measuring device plus one guess
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which zeros in a sig fig count?
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leading zeros: never
sandwiched zeros: always trailing zeros (a zero after a number, with a decimal point somewhere): always |
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if you x or ÷ sig figs how many are in the answer?
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as many as were in the original number with the least sig figs
ex. 1.1111 x 1 = 1 |
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what is accuracy?
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how close a measured value is to the real value
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what is precision?
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how reproducible a measurement is
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to add or subtract numbers in scientific notation what must be true?
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their exponents have to be the same
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when you x #'s in scientific notation what do you do with the exponents?
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you add them
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when you ÷ #'s in scientific notation what do you do with the exponents?
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you subtract them
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what is the formula for percent error?
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I error I
______ accepted value (and then times a 100) |
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matter
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anything that has mass and volume
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atom
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the smallest particle of matter that with unique properties
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liquid
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-definite volume but not shape, conforms to container
-weak bonds -atoms spread out and move randomly around |
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gas
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-no definite volume or shape; spreads out to fit container
-no bonds -bouncing off everything |
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solid
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-definite volume and shape
-strong bonds -atoms close together and vibrating |
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molecule
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a particle with two or more atoms
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pure substance
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the same type of particle throughout
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element
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same type of atom throughout
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compound
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a substance with two or more elements chemically bonded (a substance of molecules of different elements)
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mixture
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combination of two substances where each retains its own identity; more than one type of atom
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heterogeneous mixture
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not uniform througout
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homogenous mixture
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uniform throughout
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intensive property
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doesn't depend on amount of substance
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extensive property
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depends on amount of substance
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physical change
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between whole atoms or molecules
ex. changing form, cutting something |
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chemical change
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change in electrons
ex. chemical reaction, exchange of electrons |
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radioactive change
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change in nucleus
ex. radioactive decay/losing protons or neutrons |
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how many atoms are in 1 cm?
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100 million
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what did thompson do?
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discover the electron with a cathode ray tube and a magnet
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what did goldstein do?
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discover the proton with a cathode ray tube (like thompson)
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what did chadwick do?
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discover the neutron with an alpha particle shooter that shot at wax, which made neutrons come out, which went into beryllium, which came out as charged particles, and finally went into a detector. basically, when the neutrons came out he put another screen after that so they could be detected.
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what did thompson do?
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discover the dense nucleus by way of an alpha particle shooter and gold.
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what is the relative size of the electron to a neutron or proton?
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1 to 1840
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what is the mass of a neutron or proton?
an electron? |
1.67 x 10^ -24 g
9.11 x 10^-28 g |
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what is the name for the force between sub-atomic particles?
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electromagnetic force.
much stronger than gravity |
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atomic number
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number of protons
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mass number
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number of protons and neutrons
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atomic mass
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weighted average of the masses of the isotopes of an element according to their abundance in nature
(mass # x abundance) + (mass # x abundance) |
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where do all of the labels on an element go?
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mass #---------------- charge
(atom) atomic #--------------- phase |
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isotopes
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atoms of an element with different numbers of neutrons
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percent abundance
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how abundant an isotope of an isotope of an element is
# of isotope ÷ total # |
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which way do groups go?
" periods? |
groups = vertical
periods = horizontal |
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metals
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-malleable, lust, conductors
-includes aluminum, but not hydrogen -mostly solid except for Hg -lose electrons |
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metalloids
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-on the zig zag but not aluminum
-blend physical characteristics of metals and non-metals -lose or gain electrons depending |
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non-metals
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-right side of table including hydrogen
-dull, bad conductors, some diatomic -gain electrons |
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noble gases
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technically are part of non-metals
don't generally lose or gain electrons are gases at stp (standard temperature and pressure) ex. neon |
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alkali metals
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group 1
very reactive, lose electrons more reactive as you do down ex. francium |
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alkaline earth metals
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group 2
reactive but not quite as much as alkali metals ex. Be Berylium |
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transition metals
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groups 3-11
basically the d and f blocks make colors when they burn ex. Tc technetium |
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halogens
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group 17 down to iodine
most active non-metals, gain ex. I Iodine |
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diatomic elements
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exist in pairs
include the corner up by the noble gases and hydrogen ex. oxygen (o2) |
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gaseous elements at STP
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the three in the upper corner by the noble gases, plus the noble gases and hydrogen
ex. fluorine |
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liquid elements at STP
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Hg and Br
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kinetic energy
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energy in motion
ex. when an electron returns to the ground state it emits energy |
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potential energy
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energy due to position
ex. electron in excited state |
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wave/particle duality of light
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says that light is both a wave and a photon
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planck's constant
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6.626 x 10 ^ -34
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speed of light
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3.00 x 10 ^ 8
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can you name the types of rays of the whole spectrum from left to right, or smallest to biggest?
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gamma ray, xray, ultraviolet, visible, infrared, microwave, radio
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the bohr model
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says that electrons are on these quantized energy levels, and the levels get closer together as you get farther away
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if you have a higher wavelength will you have a higher or lower energy and frecuency?
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lower
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heisenberg uncertainty principle
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you can't know the velocity and position of an atom at the same time; observing one disrupts the other
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the entire model is based on...
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probability of where electrons are 95% of the time
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explain schrodinger's cat
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it was a thought experiment about a cat in a box with a vial of poison. you can't see in so you don't know if the cat is alive. according to the fundamental theories of quantum physics, (that until you've observed something it exists in every possible state) so therefore the cat is both dead and alive
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if you are observing something, you must be...
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changing it
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until you've observed it, it...
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exists in every possible state
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the shape of...
the s level the p level |
s = spherical
p = figure eight |
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what each level stands for:
n l m s |
n=level
l=sublevel m=orbital l=spin |
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the pauli exclusion principle
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it says that there can be two or less electrons per orbital, one spin up and one spin down
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degernate
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having the same energy
aka. the same sublevel |
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Hund's rule
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electrons spread out in each degenerate level before pairing up
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Aufbau principle
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electrons will fill up the orbitals from bottom to top
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