MIDTERM! Flashcards
mass vs weight
- mass is a measure of object resistance
- weight is measured through earth’s gravity
precision vs accuracy
- precision: degree of agreement among several measurements of the asme quantity
- accuracy: agreement of a particular value with its true value
random error
the measured value has an equal chance of being too high or too low (not precise, not accurate)
systematic error
the measured value will always high (or low)/ dates off by the same amount each time (precise, not accurate)
sig figs non zero integers
always count as significant figures
sig fig zero rules
- leading zeros - never count (0.0025 is only 2 sig figs)
- captive zeros - always count (1.008 is 4 sig figs)
- trailing zeros - only count if # has a decimal point
operations with sig figs
sig fig in result has the same amount of sig figs as the one with least amount of sig figs
regular notation
standard way to weight numbers
scientific notation
short handed way of writing (2.8 *10^24315)
giga (G)
10^9
mega (M)
10^6
kilo (k)
10^3
deci (d)
10^-1
centi (c)
10^-2
milli (m)
10&-3
micro (u)
10^-6
nano (n)
10^-9
pico (p)
10^-12
femto (f)
10^-15
C = (F-32) * 5/9
fahrenheit to celsius
celsius to fahrenheit
f = 9/5c + 32
celsius to kelvin
k = c + 273
matter classifies into
- pure substances
- mixtures
pure substances classifies into
- elements (one type of atom)
- compound (more than one type of atoms)
mixtures classifies into
- homogeneous (uniform)
- heterogenous (non uniform)
proton basic info
+ charge, 1 amu
neutron charge
0 charge, 1 amu
electron basic info
- charge, 1/1836 amu
isotopes
atoms of the same elements with different #s of neutrons (mass changes)
ions
charged atom (gain or lose e-) (mass doesn’t change)
atom box LABELS
- top right, mass number
- top left, charge
- bottom left, atomic #
weighted average
((relative abundance * mass of isotope) + (relative abundance * mass of isotope 2))/100
proton and electron relation
equal, unless there’s a charge
proton and neutron relation
mass # - neutrons = protons
nass # - protons = neutrons
aristotle
340 BCE
- greek philosopher aristotle thought fire, water, air, and earth were the building blocks of everything
dalton
5 part atomic theory
1) matter is made up of atoms that are indivisible and indestructible
2) all atoms of an element are identical
3) atoms of diff elements have diff weights/chemical properties
4) atoms of diff elements combine in simple whole numbers to form compounds
5) atoms cannot created or destroyed
rutherford
- scattering experiment, rutherford sent alpha particles through a thin sheet of gold
- allowed him to discover nucleus
bohr
- enhanced understanding of atomic structure and quantum theory
- proposed a model of the atom where electrons were able to occupy only certain orbits around the nucleus
jj thompson
- discovered the electron
chadwick
- discovered atoms not only consist of protons and electrons but also neutrons!
- neutral subatomic particle has around the same mass as a proton
democritus
- father of modern science
- atoms are the basic building block of matter
1) all matter consists of atoms, which cannot be further divided
2) atoms are extremely small - too small to see
3) atoms are solid particles that are indestructible
4) atoms are serrated by one another by emptiness or “void”
schrodinger & heisenberg
- schrodinger explored the idea that electrons move more like waves than particles
- his ideas led Heisenberg to develop the uncertainty principle (if an electron moved as a wave, it would be impossible to simultaneously measure both its position and momentum)
chemical properties
describe a substances ability to change to a difference substance
element
cannot be broken down chemically into simpler substance
compounds
can be broken down chemically into elements (are 2 or more atoms bounded together)
solvent
does the dissolving
solute
gets dissolved
alloy
one or more slides dissolved in another solid
lowest energy level
where electron starts from is ground state
- electron configuration written in lowest energy
- atomic spectra
excited state
- heat, electricity, or light can move up to different energy levels
- when it falls back to ground state, it gives back energy as light
returning to ground state
- may fall down in specific steps
- each step has different energy
- the further they fall, the more energy released = higher frequencies
- orbitals also have different energies inside energy levels
quantum mechanics
an explanation of how small particles behave - an explanation for subatomic particles and atoms as waves
classical mechanics
describes the motions of bodies much larger than atoms
heisenberg uncertainty principles
you cannot know both the position and momentum of an electron (where its going vs where it is)
- warner heisenberg!
ernest rutherford model
- gold foil experiment to discover dense positive piece at nucleus
- electrons move around like planets around the sun
- mostly empty space
- did NOT explain chemical properties of elements
niel bohr’s model
- move like planets around the sun
- specific circular orbits at different levels
- an amount of fixed energy separates one level from another
- electrons can jump from one level to another (circular paths)
ladder rungs
- energy level: measure of fixed energy e-
- electrons cannot between nergy levels
- you can’t stand between ladder/rungs”
UNLIKE ladders: rungs are not evenly spread
- higher level are closer together, less energy needed for jump for jump