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44 Cards in this Set
- Front
- Back
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Solids-
Liquids- Gases- |
- has definite shape and volume
- has indefinite shape and a fixed volume - has an indefinite shape and volume |
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Chemical reaction
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one or more substances change into one of more new substances
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Dalton's Atomic Theory
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1) all elements are composed of indivisible particles called atoms
2) Atoms of the same element are identical 3) Atoms can form simple whole number ratios called compounds 4) Chemical reaction occur when atoms are separated, joined, or rearranged |
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Three subatomic particles:
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Electron (negative)
Proton (positive) Neutron (no charge) |
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Formula for finding the number of neutrons
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Mass number - atomic number
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Isotopes-
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atoms that have the same number of protons but different numbers of neutrons
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Aufbau principle-
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electrons occupy the orbitals of lowest energy first
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Hunds rule
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electrons occupy orbitals of the same energy in a way that makes the number of electons with the same spin direction as large as possible
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Pauli exclusion principle
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atomic orbital may describe at most two electons
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Trends in atomic size
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Size decreases across period
and increases down groups |
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Trends in ionization energy
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Energy increases across period
Energy decreases down each group |
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Trends in Ionic Size
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Size of cations/anions decreases across the period
Size increases down groups |
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Trends in Electronegativity
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Increases across period
Decreases down groups |
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Valence electrons-
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the elctorns in the highest occupied energy level of an element's atoms
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How are cations formed?
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atoms loss of valence electrons
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How are anions formed?
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Gain of electons
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Ionic compounds have a higher
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melting point
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Covelant bond
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atoms held together by sharing electrons
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Molecule-
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a neutral group of atoms joined together by covalent bonds
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Molecular compound
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compound composed of molecules
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Coordinate covelant bond-
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is a covalent bond in which one atom contributes both bonding electrons
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Polyatomic ion
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tightly bound group of atoms that behaves as a unit (has positive or negative charge)
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Sigma bond is formed when
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two atomic orbitals combine to form a meleculat orbital that is symmetrical around the axis connecting two atomic nuclei
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According to the VSEPR theory..
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the repulsion between electron pairs casues molecular shapes to adjust so the electrons stay as far apart as possible
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A polar bond is
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a covelant bond with unequal sharing of electrons
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A molecule with two poles
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dipole
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Van der Waals forces are
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weak attractions
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A binary compound is
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composed of 2 elements that can be ionic or molecular
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To name any binary ionic compound
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place the cation name first, then the anion
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The law of definite proportions states..
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in samples of any chemical compound, the masses of the elements are always in the same proportions
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Converting the number of particles to moles
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moles= representative particles x (1 mol/ 6.02 x 10^23)
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Mole-Mass Relationship
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mass= # of moles x (mass/1 mole)
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Calculating Volume at STP
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volume= moles of gas x (22.4 L/ 1 mol)
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Percent Composition of a Compound
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% mass of element = (mass of element/mass of compound) x 100%
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Steps to solving emperical formulas
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1) Convert to moles
2) Divide each quanity by the smaller number of moles 3) Multiply by the smallest whole number that will convert both to whole number |
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Steps to SOlving a Mass-Mass Problem
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1) Change the mass of G to moles of G by using the molar mass of G.
2) Change the moles of G to moles of W by using the mole ration form the balanced equation 3) Chamge the moles of W to grams of W by using the molar mass of W. |
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Gases are easily compressed because
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of the space between the particles
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Boyles law
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for a given mass of gas at constant temperature, the volume of the gas varies inversely with pressure
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Boyles Law formula
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P1 x V1 = P2 x V2
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Charles Law
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the volume of a fixed mass of gas is directily proportional to its Kelvin temperature if the pressure is constant
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Charles Law Formula
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(V1/T1) = (V2/T2)
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Gay-Lussacs Law
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(P1/T1)=(P2/T2)
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Daltons Law formula
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Ptotal = P1 + P2 + P3 +...
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Formula for finding the percent water in a hydrate
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percent water= (mass of water/mass of hydrate) x 100
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