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Chem-1 review
A review of 1st year chemistry in preparation for AP chem
Question | Answer |
---|---|
Acid | A substance that dissolves in water to produce H+. An acid has a pH lower than 7 |
Base | A substance that dissolves in water to produce OH-. A base has a pH above 7. |
Alkali metal | A metal in group 1 of the periodic table. |
Alkaline earth metal | A metal in group 2 of the periodic table. |
Alpha particle/ alpha decay | Radioactive decay in which a helium nucleus (2 protons and 2 neutrons) is shot out of the nucleus of an atom. Least penetrating form of radiation. |
Anion | A negative ion. |
Cation | A positive ion. |
Atom | Smallest particle of an element that retains the chemical properties of that element. |
Atomic mass | Average mass of an atom including protons and neutrons. Different isotopes have different atomic masses due to a difference in the number of neutrons. |
Atomic orbital | A region where an electron is located. Each orbital can hold 2 electrons. Orbitals are labeled s, p, d, f, etc. |
Atomic radius | On-half the distance between two nuclei of an element. |
Atomic emission spectrum | Diagram showing the wavelengths at which light is emitted by excited electrons in an atom. |
Dalton's atomic theory | Atoms of a given element are the same, all matter is made of particles called atoms, atoms cannot be created or destroyed, atoms are indivisible. |
Avogadro's number | 6.02 x 10^23 |
Balanced chemical equation | An equation for a reaction that has the same number of atoms of each element on both sides. |
Bent molecule | The shape of a water molecule or any molecule with 2 lone pairs and 2 shared pairs. |
Beta radiation | Electron emission from unstable nuclei. 2nd most penetrating form of radiation. |
Bohr model of the atom | Electrons are found in energy levels around the nucleus. When electrons drop from one energy level to another, a photon is emitted. |
Boiling point elevation | Increase in the boiling point of a solution when a solute is added. |
Covalent bond | A bond where electrons are shared and the electronegativity difference is less than 1.7. Typically occurs between non-metals. |
Ionic bond | A bond where electrons are transferred and the electronegativity difference is more than 1.7. Typically occurs between a metal and a non-metal. |
Hydrogen bond (force) | An intermoelcular force where the bond between H and F,O, or N attracts another molecule. It is a force between 2 molecules, not between 2 atoms. |
Double bond | A covalent bond where 4 electrons are shared. |
Non-polar covalent bond | A bond between 2 atoms where there is no electronegativity difference. |
Polar covalent bond | A bond between 2 atoms where the electronegativity difference is greater than 0 but less than 1.7. |
Metallic bond | A bond type where electrons are delocalized. The "sea of electrons". |
Calorimeter | Device used to measure the transfer of heat. |
Catalyst | A species added to a reaction that speeds up the reaction without being consumed in the reaction. |
Concentration | The ratio of solvent to solute. Can be measured in molarity, molality, etc. |
Dipole-Dipole force | The intermolecular force of attraction between 2 polar molecules. |
Dispersion force | The intermolecular force of attraction between 2 nonpolar molecules. Very weak. Also called Van der Waals forces. |
Electron | The negatively charged particle with 0 mass found outside the nucleus of the atom. |
Electron configuration | An expression giving the number of electrons in each orbital. Ex: 1s2,2s2,2p6,3s2. |
VSEPR theory | Theory stating that valence shell electrons repel each other and determine the shape of a molecule (bent, trigonal pyramidal, etc.). |
Electronegativity | The amount of pull a nucleus has on an electron. |
Element | A substance whose atoms are all chemically the same (containing the same number of protons). |
Endothermic | A process where heat is absorbed. Typically feels cool to the touch. |
Exothermic | A process where heat is released. Typically feels warm to the touch. |
Equilibrium | A state of balance where the rate of the forward reaction equals the rate of the reverse reaction (the amounts of reactants and products are NOT necessarily equal!). |
Excited state | A state where an electron contains more energy than the ground state. (The electron has "jumped" a level) |
Experimental yield | The amount of product actually produced in a reaction. |
Theoretical yield | The amount of product a reaction is predicted to make based on stoichiometry calculations. |
Percent yield | The ration of experimental yield to theoritical yield. |
Empirical formula | The chemical formula of a substance with the ratio reduced to lowest terms. For example-the empirical formula of C2H8 is CH4. |
Freezing point depression | Phenomenon where the freezing point of a solution is lowered when a solute is added. |
Frequency | The number of wave cycles in a given amount of time (usually seconds). Measured in hertz. |
Gamma radiation | High-energy radiation occurring when photons are emitted from the nucleus. |
Halogen | An element in group 7 of the periodic table. |
Specific heat capacity | The amount of heat required to raise the temperature of 1 g of a substance 1 degree celsius. |
Rutherford model | Rutherford did the gold foil experiment and found that atoms have a dense center containing the atom's mass and the majority of the atom is empty space. |
Thompson's model (Plum Pudding) | Thompson did the cathode ray experiment and found that the cathode ray was attracted to the positive end of a magnet. This showed that atoms were made of subatomic particles with charge. |
Diatomic | Br,I,N,Cl,H,O,F. Elements that are found in pairs in their natural state. |
Ion | A charged species where the number of protons is not the same as the number of electrons. |
Ionization energy | The energy that is required to remove an electron from an atom. |
Isotope | An atom having the same number of protons as another atom but with different numbers of neutrons. |
Joule | Unit of heat. |
Law of conservation of energy | Energy cannot be created or destroyed. |
Law of conservation of mass | Matter cannot be created or destroyed. |
Lewis dost structure | A diagram showing the arrangement of the valence electrons of an atom. |
Limiting reactant | The reactant that "runs out first". It determines how much product can be made. |
Metal | A substance with luster, malleability, and high electrical conductivity. |
Metalloid | A substance such as Si that has properties of both metals and non-metals. |
Non-metal | A substance without luster, brittle, and low electrical conductivity. |
Molar mass | The weight (in grams) of one mole of a substance. |
Molarity | A concentration unit defined to be the number of moles of solute per one liter of solution. |
Mole | A collection of 6.02 x 10^23 particles. |
Neutral solution | A solution with a pH of 7 |
Neutron | A particle in an atomic nucleus with a mass of 1 amu and no charge. |
Noble gas | An element in group 18 of the periodic table. |
Octet rule | Rule stating atoms tend to acquire 8 electrons. |
Orbital | Region in space with a high probability of finding an electron. |
Period | A horizontal row of the periodic table. |
Photon | A particle of light or energy. |
Precipitate | The solid formed in a double replacement reaction. |
Proton | A positively charged subatomic particle located in the nucleus with a charge of +1 and a mass of 1 amu. |
Significant figure | A meaningful digit in a measurement. |
Solute | The "thing that gets dissolved". |
Solvent | A substance, usually a liquid, that makes up the major component of a solution. |
Sublimation | A change in state from a solid to a gas. |
Transition metal | A metal in the d-block of the periodic table. |
Valence electron | An electron in an outer energy shell. |
Wavelength | The distance between peak to peak or trough to trough of a wave. |