GIANT FINALS STUDY SESH Flashcards
science
the knowledge obtained by observing natural events and conditions in order to discover facts and formulate laws or principles that can be verified or tested
chemistry
the study of the composition, structure, and properties of matter and the changes that matter undergoes
composition: what a molecule is made up of (i.e. matter, atoms)
structure: the shape that gives a molecule it’s properties
chemical
any substance that has a definite composition or is used or produced in a chemical process
definite composition: ethanol
basic vs applied research
basic: carried out to increase general knowledge
applied: carried out to solve practical problems
matter vs mass
matter: has mass and takes up space
mass: a measure of the amount of matter
chemical properties
a substance’s ability to undergo changes (a reaction) that alter its composition and identity
element vs compound
element: composed of one kind of atom
compound: made from two or more elements in fixed proportions
physical vs chemical changes
physical: the identity of a substance IS NOT changed
(i. e. change of state, crumbling)
chemical: the identity of a substance CHANGES
(i. e. combustion, oxidation)
what are the three major states of matter?
solid, liquid, gas
anything that happens with matter requires…
energy!!!
- energy accompanies both physical and chemical changes
energy, mass, and matter are neither…
created nor destroyed
mixtures vs pure substances
mixtures: two or more different substances joined together (not chemically)
pure substances: consisting of one element or compound
periodic table
an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column
- elements organized by chemical properties
- columns = groups
- rows = periods
- same periods = same outer valence shell configuration
- same groups = similar properties
s-block, p-block, d-block, and f-block
what are the different classifications?
- metals: shiny, malleable, ductile, good conductors
- nonmetals: brittle, poor conductors
- metalloids: intermediate in properties between metals and nonmetals
- noble gases: unreactive
scientific method
a logical approach to solving problems that lend themselves to investigation
hypothesis vs theory
hypothesis: a TESTABLE statement that serves as the basis for predictions and further experiments
(if. .. then…)
theory: a broad generalization that explains a body of known facts or phenomena
- can change over time
what is the result of nearly every measurement?
a number and a unit
SI system
a system of measurement used in science consisting of…
- meters (length)
- kilograms (mass)
- seconds (time)
- kelvin (temperature)
- mole (amount of substance)
weight
a measure of the gravitational pull on matter
derived SI units
- square meter (area)
- cubic meter (volume)
density
- the level of compactness of a substance
- the ration of mass to volume
- density = mass/volume
conversion factors
used to convert from one unit to another
accuracy vs precision
accuracy: the closeness of a measurement to the correct or accepted value
precision: the closeness of values for a set of measurements
significant figures
consist of all digits known with certainty plus one final digit, which is uncertain
- answer should have the same amt of sigfigs as the number that has the fewest sigfigs
exact conversion factors
completely certain and do not limit the number of digits in a calculation
i.e. avogadro’s number
directly vs inversely proportional
directly proportional: dividing one by the other yields a constant value
- increase in a = increase in b
- a/b = c
inversely proportional: their product has a constant value
- ab = c
- increase in a = decrease in b
history of atoms
- atoms have been around since ancient Greece
- in the 19th century, John Dalton proposed a scientific theory of atoms than can still be used to explain properties of most chemicals today
mass ratios
- always the same, regardless of how much of the compound there is or how it was formed
- if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element can be expressed as a ration of small whole numbers
cathode-ray tubes
supply evidence of the existence of electrons, which are negatively charged subatomic particles that have relatively little mass
- measured the charge-to-mass ratio of an electron
properties of the nucleus
- positive
- small
- dense
atomic nuclei
- Rutherford found evidence for the existence of the atomic nucleus by bombarding gold foil with a beam of positively charged particles
- atomic nuclei are composed of protons and electrons
- atomic nuclei have a radii of about 0.001 pm and atoms have a radii of about 40-270 pm
protons vs neutrons vs electrons
protons: electric charge of +1
electrons: electric charge of -1
neutrons: no electric charge
atomic number vs mass number
atomic number: equal to the number of protons of an atom
mass number: equal to the total number of protons and neutrons that make up the nucleus of an atom
unified atomic mass unit
based on the carbon-12 atom and is a unit for measuring the mass of atoms
- equals 1.660 540 x10^23