Term
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Definition
- amount of matter in a sample
- matter = anything that occupies space & has mass
- grams, milligrams, kilograms
- more mass means more atoms/molecules
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Term
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Definition
- how much space sometimg takes up
- usually liters or milliliters
- 1 cm3 = 1 mL
- measure liquid volume with measuring flask
- measure solid volume with displacement
- gas volume = volume of container (displacement with container if necessary)
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Term
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Definition
- ratio of mass to volume of an object
- each substance has a specific density
- d = m/v
- density of liquids and solids as a fixed temp is constant
- density of gases changes
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Term
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Definition
- force that gas in a closed container exerts on the container walls
- solid/liquid is there, gas exerts presh on walls of environment and everything in it including the solid/liquid
- use manometer or barometer to measure (both use Hg)
- 760 torr = 760 mmHg = 1 atm
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Term
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Definition
- the ability to do work or transfer heat
- heat, light, kinetic, chemical bond energy (different forms)
- usually kinetic energy of molecules in chem--greater KE means higher temp and faster movement
- breaking bonds takes energy, forming them releases energy
- heat is the transfer of KE from one thing to another
- 1 cal = 4.186 J; 1000 J = 1 kJ
- measure it with a calorimeter
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Term
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Definition
- heat is energy flow from high temp thing to low temp thing
- temp measures average KE of molecules in a sample
- if something increases in temp, that's a heat content increase
- substances have different specific heats
- K = C + 273; 0 K = -273 C; 0 C = 273 K
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Term
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Definition
- it's easier to heat some things than others
- heat capacity is how much energy something has to absorb for some of it to be raised 1 degree Celsius
- specific heat is the heat capacity for 1 g of the substance
- q = mst
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Term
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Definition
- smallest particle of an element
- retains the chemical properties of the element
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Term
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Definition
- proton, positive charge
- neutron, no charge
- nucleons, in the nucleus, protons and neutrons
- electrons, negative charge
- nucleons have mass; electrons have practically none
- neutrons determine the isotope
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Term
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Definition
- atom with unequal charges inside and outside nucleus
- cation, positively charged
- anion, negatively charged
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Term
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Definition
- most fundamental unit of matter
- can't break it down without losing its identity
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Term
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Definition
- horizontal rows are periods
- vertical columns are groups
- all elements in the same group have the same number of electrons in outer shells and share properties
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Term
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Definition
- number of protons in the nucleus of an atom
- specific to the element
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Term
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Definition
- protons and neutrons have 1 amu mass
- sum of an atom's proton and neutrons is the mass number
- isotopes have different numbers of neutrons in their nuclei
- doesn't appear on the table because it varies
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Term
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Definition
- average mass number, so it's based on each isotope's natural abundance
- one for each element
- listed on the table
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Term
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Definition
- units of two or more atoms
- held together with chemical bonds
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Term
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Definition
- molecule made of just two atoms
- some elements exist this way at stp: O2, I2, H2, N2, Cl2, F2, Br2
- Clearly I Have NO Friends, Bro
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Term
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Definition
- add the atomic weights of all the atoms in the molecule
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Term
| 3. Empirical Formula and Molecular Formula |
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Definition
- empirical formula is the ratio of atoms within a molecule
- the molecular formula divided by the gcf of the subscripts gives the empirical formula
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Term
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Definition
- refers to percent by mass
- find it by calculating stuff :P
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Term
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Definition
- a mole of something is 6.022 x 1023
- the 6 number is called Avogadro's number
- a mole of atoms make up the atomic mass
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Term
| 3. Mass Composition to Empirical Formula |
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Definition
- imagine 100g
- convert percents to grams
- convert grams to moles
- find the ratio between the mole amounts
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Term
| 3. Stoichiometry Problems |
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Definition
- how much product or reactant is produced or needed in a reaction?
- always start with a balanced equation
- remember limiting reactants
- convert things to moles!
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Term
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Definition
- S symbol
- If deltaS is negative, reaction loses entropy
- If deltaS is positive, reaction gains entropy
- Universe tends towards disorder
- Low energy states ar emore stable than high energy states
- Higher S + Lower E = More Stable
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Term
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Definition
- term refers to energy states of reactions or products
- symbolized with H
- decreasing H leads to stability
- H decreases: exothermic; H increases: endothermic
- endothermic reactions need energy input
- energy of products/reactions refers to the energy in the bonds
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Term
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Definition
- amount of heat released or absorbed when a mole of a compound is formed
- if Hf is negative, then exothermic, and vice versa
- for all elements, the heat of formation is zero
- heat of formation for entire reaction = sum of product Hfs minus sum of reactant Hfs
- Hess's Law
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Term
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Definition
- If a reaction happens in more than one step, the change in enthalpy for the whole thing is the sum of the changes in enthalpy for each step
- Enthalpy is pathway-independent: state function
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Term
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Definition
- happens without energy input
- can happen for a positive H if S is low enough
- can happen for a positive S if H is low enough
- spontaneity is determined by Gibbs free energy
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Term
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Definition
- ΔG = ΔH - TΔS
- T is in Kelvins
- determines if a reaction will happen spontaneously or not
- if ΔG < 0, then it's spontaneous in that direction
- if ΔG > 0, then it's spontaneous in the opposite direction
- if ΔG = 0, then there's equilibrium
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Term
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Definition
- our current theory about how electrons and atoms work
- a quantum is a small unit of energy, and all energy is quantized, so all energy exists in multiples of quanta
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Term
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Definition
- electrons exist in them
- replaces Bohr model of orbiting
- describes the likelihood that an electron will be found in a particular location--a probability function
- orbitals have energy shells, shape, subshells
- any orbital holds two electrons
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Term
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Definition
- each orbital is in an energy shell
- higher number energy shell
- greater energy
- farther from nucleus
- each energy shell has a whole number
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Term
| 4. Orbital Shape and Subshell |
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Definition
- 4 different shapes that make up subshells
- s has 1 orbital
- p has 3 orbitals
- d has 5 orbitals
- f has 7 orbitals
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Term
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Definition
- it's impossible to know both the position and momentum of an electron at the same time
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Term
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Definition
- matter has the properties of a wave
- electrons behave in waves like electromagnetic radiation
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Term
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Definition
- wrong
- electrons orbit the nucleus in true orbits, like how planets orbit the sun
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Term
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Definition
- each subshell is filled before electrons go in the next subshell
- Cr and Cu are exceptions (promote a 4s to a 3d)
- Hybrid orbitals are exceptions
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Term
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Definition
- Unstable nucleus undergoes nuclear decay --> radioactive --> releases radioactivity
- radioactive particles
- as a radioactive atom decays
- becomes another isotope or
- becomes another element
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Term
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Definition
- Detects and measures radioactive particles
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Term
| 4. Four Types of Radioactive Decay |
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Definition
- alpha decay
- beta decay
- positron emission
- gamma decay
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Term
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Definition
- emits alpha particle: 2 pros and 2 neus
- decreases atomic # by 2 and atomic mass by 4
- sometimes symbolized as 4/2He
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Term
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Definition
- emits a beta particle: one electron
- releases an electron from a neutron --> lose neutron and gain proton
- atomic # increases by 1 and mass stays the same
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Term
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Definition
- releases positron: antiparticle of an electron, same magnitude but opposite charge
- proton becomes a neutron
- decreases atomic # by 1, mass stays the same
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Term
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Definition
- emits gamma rays when the atom has too much energy
- makes nucleus more stable but doesn't do anything else
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Term
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Definition
- rate of a substance's radioactive decay
- takes one half-life for half of the substance to decay
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Term
| 5. Horizontal and Vertical Similarities |
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Definition
- same row (period) --> electrons in same energy shells
- same column (group) --> similar chemical and physical properties
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Term
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Definition
- same column
- noble gases
- alkali metals
- alkaline earth metals
- halogens
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Term
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Definition
- group 1/1A
- 1 valence electron
- very reactive
- snihy, grayish-white
- melt easily
- lower densities than other metals
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Term
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Definition
- group 2/2A
- 2 valence electrons
- less reactive than alkali metals but more reactive than other metals
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Term
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Definition
- Alkali metals
- Alkaline earth metals
- they're really reactive...duh
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Term
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Definition
- group 17/7A
- 7 valence electrons
- very reactive
- look different from each other
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Term
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Definition
- shiny and conduct heat well
- malleable and ductile
- all solid at room temp except mercury
- lose electrons in bonds
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Term
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Definition
- share or gain electrons in bonds
- poor conductors of heat and electricity
- some are solid, liquid, gas at room temp
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Term
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Definition
- some characteristics of metals and nonmentals
- can either gain or lose electrons in a bond
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Term
| 5. Periodic trends to know |
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Definition
- Ionization energy
- Electronegativity
- Atomic radius
- Metallic character
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Term
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Definition
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Term
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Definition
- energy required to remove an electron from an atom
- increases towards fluorine
- 1st, 2nd, etc.
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Term
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Definition
- pull that a nucleus exerts on electrons of another atom
- increases towards fluorine
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Term
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Definition
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Term
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Definition
- energy required to completely separate a mole of a solid ionic compound into separate ions
- higer lattice energy = stronger bond
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Term
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Definition
- attraction betweena positive charge and a negative charge
- strong
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Term
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Definition
- middle of the periodic table
- harder than metals
- higher melting point than metals
- compounds with transition metals are colorful
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Term
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Definition
- molecules of an ideal gas don't attract or repel each other
- molecules of an ideal gas occupy zero volume
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Term
| 6. Kinetic Molecular Theory |
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Definition
- kinetic energy of a gas molecule increases proportionally with temperature in K
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Term
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Definition
- atoms bonded by covalent bonds in a continuous network
- one big macromolecule
- no individual molecules
- e.g. diamonds or quartz
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Term
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Definition
- Ionic substance where water molecules bond to the ions in a fixed ratio
- dot H2O means it's a hydrate
- % comp of water by mass in a hydrate is called water of hydration
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Term
| 6. Four Types of Crystalline Solids |
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Definition
- Ionic
- Covalent network
- Molecular
- Metallic
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Term
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Definition
- amount of heat it takes for a substance to go from solid to liquid
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Term
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Definition
- Amount of heat it takes for a substance to go from liquid to gas
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Term
| 6. Phase change and presh |
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Definition
- more pressure means it's harder to get solids to melt or liquids to vaporize
- more presssure does the opposite for water--easier to melt
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Term
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Definition
- a particular temperature and pressure
- substance can exist as a solid, liquid, or gas
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Term
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Definition
- created when liquids below their boiling points evaporate
- all liquids in a closed system exert some
- higher vapor presh means more volatility
- affected by intermolecular forces, temperature, and molecular weight
- boiling
- all of the presh above a liquid is vapor presh
- vapor presh = atmospheric presh
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Term
| 6. Energy and Phase Change |
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Definition
- solid -----------> gas
- low PE --------> high PE, which universe dislikes
- low entropy --> high entropy, which universe likes
- melting/boiling is spontaneous when the temperature is above the melting/boiling point
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Term
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Definition
- M
- M = moles of solute/liters of solution
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Term
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Definition
- m
- m = moles of solute/kilograms of solvent
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Term
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Definition
- Solids
- more soluble at higher temperatures
- Gases
- less soluble at higher temperatures
- more soluble at higher presh
- think about carbonated drinks
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Term
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Definition
- ions in solution
- makes the solution about to conduct electricity
- the solution is still neutral
- in ionic solutions aka elecrolytic solutions
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Term
| 7. Solutes and Freezing/Boiling Points |
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Definition
- ΔT = kmi
- solute effects an increase in boiling point and decrease in freezing point
- k changes from solvent to solvent
- m = molality
- i = the number of particles it dissolves into per mole
- sucrose: i = 1
- NaCl: i = 2
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Term
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Definition
- solid substance that settles out of a solution
- often the result of a double replacement reaction
- use solutbility rules
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Term
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Definition
- all nitrates and perchlorates are soluble
- all alkali metal and ammonium compounds are soluble
- hydroxides are insoluble except alkali metals and BaOH
- silver, lead, and mercury salts are insoluble except with nitrates and perchlorates
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Term
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Definition
- study of the rates of reactions
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Term
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Definition
- the point in a chemical reaction at which concentration of reactants and products ceases to change
- forward and reverse reaction rates are equal
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Term
| 8. Activated Complex/Transition State |
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Definition
- unstable
- place where products form
- need to reach activation energy before activated complex can form
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Term
| 8. Factors that affect likelihood of reactions |
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Definition
- frequency of collision
- concentration of reactants
- surface area of reactants
- temperature
- energy of collision
- temperature
- nature of reactants
- catalysts
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Term
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Definition
- increase rate of reaction by lowering activation energy
- not consumed in a reaction
- don't change the equilibrium of a reaction
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Term
| 8. Equilibrium constant expression |
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Definition
- reaction: aA + bB <---> cC + dD
- Keq = ([C]c [D]d)/([A]a [B]b)
- solvents not included
- powers are coefficients from the equation
- Keq = products/reactants
- if > 1 then forward reaction favored
- if < 1 then reverse reaction favored
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Term
| 8. Le Chatelier's Principle |
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Definition
- add more on one side --> equilibrium shifts to other side
- Keq stays constant unless temperature changes
- if stress is placed on a reaction at equilibrium, then the equilibrium will shift in a direction that relieves the stress
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Term
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Definition
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Term
| 8. Pressure Change Effect on Equilibrium |
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Definition
- only applies if some of the things in the reaction are gases
- reduce volume --> increase pressure --> equilibrium shifts to side with fewer moles of gas
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Term
| 8. Solubility Product Constant |
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Definition
- Ksp
- Equilibrium constant between insoluble ionic solid and dissolved ions
- The values are usually really small
- Solids aren't included in normal equilibrium expressions
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Term
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Definition
- spontaneous dissociation of water tha tmakes H+ and OH- ions
- reversible
- an equilibrium exists between H+, OH-, and H2O
- equilibrium expression for it is 10-14 M2 at 25 degrees C
- same in every aqueous solution
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Term
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Definition
- "p" means -log
- if [H+] = 10-7 M, then pH = 7
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Term
| 9. Different Definitions for Acid and Base |
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Definition
- Arrhenius
- Acids make H+ in aq
- Bases make OH- in aq
- Lewis
- acids accept electrons in aq
- bases donate electrons in aq
- Bronsted-Lowry
- acids donate protons (H+)
- bases accept protons
- most common definition currently
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Term
| 9. Acid Dissociation Equations |
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Definition
- HA(aq) --> H+(aq) + A-(aq)
- or
- HA(aq) + H2O(l) --> H3O+(aq) + A-(aq)
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Term
| 9. Base Reaction Equations |
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Definition
- A-(aq) + H+(aq) --> HA(aq)
- or
- A-(aq) + H2O(l) --> HA(aq) + OH-(aq)
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Term
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Definition
- molecules or ions that can act as acids or bases depending on the solution
- most molecules are either acids or bases
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Term
| 9. Strong Acids and Bases |
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Definition
- completely dissociate
- dissociation is 100% irreversible
- one-way arrow
- pH of 1.0 M strong acid is always 0
- pH of 1.0 M strong base is always 14
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Term
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Definition
- HCl
- HBr
- HI
- HNO3
- H2SO4 (only the first H is strong)
- HClO4
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Term
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Definition
- LiOH
- NaOH
- KOH
- other group 1 hydroxides
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Term
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Definition
- partially and reversibly dissociate
- use the reversible arrow
- figure out if something's acidic or basic, then it's weak if it isn't on the strong list
- remember that pH + pOH = 14 at 25 degrees C
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Term
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Definition
- molecules that are the same except one has an extra H+
- the one with the extra H+ is the onjugate acid
- the one with fewer H+ is the conjugate base
- doesn't necessarily mean that they're an acid and a base
- there's an ionic equilibrium between the conjugates
- sum of pKa and pKb of conjugates always = 14 at 25 C
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Term
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Definition
- Conjugate acid of a strong base is neutral
- Conjugate base of a strong acid is neutral
- Conjugate acid of a weak base is an acid
- Conjugate base of a weak acid is a base
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Term
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Definition
- minimize a change in pH when an additional acid or base goes into a solution
- a conjugate pair of a weak acid and a weak base so they don't neutralize each other
- use Henderson-Hasselbalch equation to calculate pH
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Term
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Definition
- Sum of oxidation states in a compound is zero
- Oxygen: -2
- Alkali metals: +1
- Alkaline Earth Metals: +2
- Halogens: -1
- Hydrogen: ±1
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Term
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Definition
- gets reduced
- causes something else to get oxidized
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Term
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Definition
- gets oxidized
- causes someone else to be reduced
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