Chemistry Exam Review
Terms
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- volume
- L x W x H
- potential energy
- stored energy
- kinetic energy
- energy of movement
- radiant energy
- energy in motion
- true or false: zeros used for spacing the decimal point are significant.
- false
- Law of Conservation of Energy
- Energy changes form
- Law of conservation of matter
- All matter/atoms are the same, never has changed, never will change.
- Law of conservation of mass-energy
- Matter gets transformed into energy and vice versa
- List five indications of chemical changes
- burns, color, bubbles, change in heat/energy change, explosions, rust, smoke
- "ide" means the chemical is --charged
- negatively
- "ium" means the chemical is -- charged
- positively
- Bromide
- Br-1
- Sulfide
- S2-
- Sulfur
- S
- Nitride
- N3-
- Chloride
- Cl-
- Oxide
- O2-
- Oxygen
- O2+
- Phosphide
- P3-
- Phosphorous
- P
- Flouride
- F-
- Magnesium
- Mg2+
- Aluminum
- Al3+
- iodide
- I-
- Phosphate
- Po4 up 3-
- Ammonium
- NH4+
- Sulfate
- SO4 up 2-
- Iron II
- Fe2+
- Iron III
- Fe3+
- Nitrate
- NO3-
- Nickel II
- Ni2+
- Potassium
- K+
- Zinc
- Zn2+
- Sodium
- Na+
- Acetate
- CH3COO-
- Copper I
- Cu+
- Copper II
- Cu2+
- Calcium
- Ca2+
- Hydrogen
- H+; when diatomic H2+
- Carbonate
- CO3 up 2-
- Lithium
- Li+
- Silver
- Ag+
- Hypochlorite
- OCl-
- daltons atomic theory of matter
-
1. each element is made of extremely small particles (atoms)
2. All atoms in a given element are identical, but they differ from those of any other element
3. Atoms are neither created nor destroyed in any chemical reaction
4. A given compound always has the same relative numbers and kind of atoms - atoms combine to form
- substances
- atoms are made of particles that have an--
- electric charge
- ion
- an atom that is electrically charged (+/-)
- cation
- an ion with a + charge
- anion
- an ion with a - charge
- cobalt III
- Co3+
- cobalt II
- Co2+
- ions of different elements combine to form
- ionic compound
- chemical formula
- tells us what kind of atoms/ions and how many/ratio
- compounds are electronically
- neutral
- the formula of an ionic compound should be
- reduced to give the smallest whole number ratio of ions
- process by which a substance or substances are converted into different substances with new chemical and physical properties
- chemical reaction
- list five examples of chemical reactions
-
metal>rust
dough>bread
leaves changing color
hair perm - what happens in a chemical reaction?
- reactants are converted into products
- a chemical equation describes:
- exactly what happens in a chemical reaction
- list the five types of chemical reactions
-
1. Direct Combination/Synthesis
2. Decomposition
3. Single-Replacement
4. Double-Replacement
5. Combustion - Atoms that were -- replace other atoms that were --; atoms that were -- replace other atoms that were --!
- For single and double replacement reactions, --cations, cations, anions, anions
- when reactants react in a combustion rection, they always give off
- CO2 and H20
- atomic mass
-
the mass of a single atom (not in grams) given/measures in amu's (atomic mass unit)
atomic mass of any atom is based on the mass of a carbon atom
it's at the bottom of the square on periodic table - formula mass
- sum of masses of all atoms in a compound
- mole
- the number of atoms of the element=the number of atoms in 12.0 g carbon-12
- molar mass
- the mass of a mole of a substance, or the mass of 6.02 x 10 up 23 particles of that substance
- molar mass is the same thing as:
- atomic mass
- for a compound, molar mass is the same thing as:
- formula mass
- converting from mass-moles
- molar mass (g/mol)
- converting from volume to moles
- 22.4 Liters (only at STP)
- converting from particles to moles
- 6.02 x 10 up 23
- moles-moles conversion
- ratio of moles in the equation
- at a temperature of 0 degrees celcius, and a pressure of 1 atmosphere, 1 mole of any gas has a volume of
- 22.4 L...this is STP which stands for standard temperature and pressure
- percent composition
- the percent of the mass of compound made up by each element
- empirical formula
- formula that gives us the lowest whole number ratio of atoms in a covalent compound
- molecular formula
-
formula giving actual numer of atoms in a covalent compound; not necessarily lowest terms
*in order to find molecular you have to find empirical - using chemical formulas and equations to figure out amounts of substances that undergo chemical changes
- stoichiometry
- matter is neither created nor destroyed, atoms cannot be gained or lost, even during a chemical reaction nothing is destroyed it just changes, the total mass of the reactants in a chemical reaction must equal the mass of the products.
- law of conservation of matter
- balanced chemical equations give us both the relative number of -- and the relative number of ---
- --atoms/particles---moles
- the reactant thats used up in a chemical reaction
- limiting reagent
- the reactant that's left over in a chemical reaction
- excess reagent
- the limiting reagent determines
- how much product is formed!
- in chemical reactions, atoms are rearaanged and new substances are formed. based on these arrangements, chemical reactions can either absorb or release--
- energy
- the energy exchanged between objects due to a difference in temperature
- heat
- study of changes in heat that accompany chemical reactions (chemistry having to do with heat)
- thermochemistry
- exothermic reaction
- reaction that gives off or releases heat into the surroundings (-)
- endothermic reaction
- reaction that takes in or absorbs heat from the surroundings
- measure of heat absorbed or released by a chemical reaction occurring at constant pressure
- enthalpy change
- enthalpy change for reactants in their standard state being converted to products in standard state.
- standard enthalpy change
- standard state (for enthalpy change)
- 1 atm and 25 degrees celcius
- caloric theory
- early scientists thought heat was an invisible, weightless liquid that flowed from hotter objects to cooler objects
- kinetic theory
-
currently accepted; heat comes from the motion and vibrations of particles of matter.
heat is the transfer of kinetic energy (of motion) from a hotter object to a cooler one (at the atomic level so it's not visible) - an exothermic reaction releases heat, so the temperature of the surroundings
- increase
- an endothermic reaction absorbs heat, so the temperature of the surroundings
- decreases
- calorimetry
- the study of heat flowand heat measurement, allows scientists to measure the standard enthalpy change by using calorimeter.
- specific heat
- the amount of heat required to raise 1gram of a substance by 1 degree celcius
- describe a proton and its (charges, mass, and location)
-
charge of +1
mass of 1 amu
location- in the nucleus - describe an electron (charge, mass, location)
-
-1 charge
mass, so small we ignore
located outside nucleus -
neutrons
describe location, charge, mass -
no charge, neutral
mass about 1 amu
located inside nucleus - mass number
-
the sum of the protons and neutrons
found by taking the # protons and adding to the # neutrons - how do you know how many electrons there are?
- there are the same number of electrons as neutrons, unless it has a charge in which case if it's positive there is one more electron and if it's negative that means there is one less
- recall what you know about the electron
-
electrons only have specific energies
electrons have wavelike properties
we cant know the location and where the electron is going at the same time - What does the quantum mechanical model do?
- describes the electron using the idea of ELECTRON DENSITY
- region around the nucleus where there is a high probability of finding an electron of a given energy.
- orbital
- gives a definite electron path
- orbit
- lowest energy orbital to highest in letters; number of orbitals each one holds, and shapes
-
s, p, d, f
1 3 5 7
s=sphere
p=dumbbell
d, f =complex - if the quantum number/principal energy level is n=3, how many sublevels are there?
- 3
- describe the characteristics of metals
-
location: left of zigzag
properties: shiny
good conductors of energy
solids at room temperature
malleable (can be hammered into a thin sheet)
ductile (can be pulled into thin wires) - properties of nonmetals
-
right of zigzag
not shiny
poor conductors of heat and electricity
may be solids, liquids, or gases
neither melleable, or ductile - semimetals
- touching zz line
- valence electrons
- electrons that occupy the highest principle energy level/have highest quantum number level, determine chemical reactivity of the atom
- periodic law
- when the elements are arrangedin order of increasing atomic number, we can see the trends in their chemical and physical properties
- groups
- vertical columns in periodic table
- periods
- horizontal rows in periodic table
- alkali metals, alkaline earth metals, halogens, noble gases
- groups in periodic table
- atomic radius
- distance from center of nucleus to outermost electron
- as you move down a column
-
atomic radius increases
ionization energy decreases
electronegativity decreases - a cation is -- than the corresponding neutral atom
- because it has lost an electron making it positive, it is --smaller
- an anion is -- than its corresponding neutral atom
- because it has gained an electron, it is larger than its corresponding neutral atom
- metals form
- cations
- nonmetals form
- anions
- ionization energy
- energy required to remove an electron from and atom or an ion
- as you move across a period, the
-
atomic radius decreases
ionization energy increases
electronegativity increases - electron affinity
- the energy abosorbed (required) or released for an atom or ion to gain an electron
- the closer an atom is to filling its valence shell, the --its electron affinity
- greater; because more energy is released and it wants an electrom
- the atom's ability to attract electrons
- electronegativity
- electrons are only allowed to have certain - corresponding to different amounts of -- (ie. the energy of an electron is --)
- orbits, energies, quantized.
- when an electron is falling back down to its ground state, -- is emitted
- light
- frequency determines the -- of the light emitted when an electron drops back down to its ground state
- color
- excited state
- higher energy level so in order for an electron to be in an Excited state, something would have to happen to it (further from nucleus, higher energy)
- DEBROGLIE and matter waves
-
he predicted that all moving objects exhibit wavelike behavior; electrons have wavelike properties
he related mass-wavelength - HEISENBERG uncertainty principle
-
you cannot know the precise location of an object and exactly where it is going at the same time
makes no difference for larger objects - how does the heisenberg uncertainty principle affect a tiny particle like an electron
- to locate an electron, you have to shine light on it, and by doing so, by hitting it with photons, its path is being changed
- height of wave
- amplitude
- wavelength
- distance from crest to crest
- how fast the wave moves back and forth in a given amount of time
- frequency
- less wavelength =
- larger frequency
- larger wavelength=
- smaller frequency
- speed
- how fast the wave moves through space
- photons-
- light particles carrying small amounts of energy
- photoelectric effect-
- when light was shined on certain metals, electrons were emitted
- light is dual natured it is:
- wave and particle
- red- what level energy
- low energy, lower frequency
- violet- what level energy
- higher energy, higher frequency
- planck's quantum theory/equation
-
objects can only abosorb or release energy in fixed amounts, called quanta
e=hv relates energy of wave to frequency - the aufbau principle
- electrons are put into the lowest enerfy orbitals one at a time until all of the electrons are accounted for
- the number of electrons in a neutral atom= # of protons =
- atomic #
- list the diagonal rule
- 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 5f, 6s, 6p, 6d, 6f
- the pauli exclusion principle
- when two electrons are in the same orbital, they will spin in opposite directions (have opposite spins) two arrows, one goes up, one down
- hund's rule
- in a given sublevel, one electron will go into each orbital before beginning to pair