Final Exam Vocab – Flashcards
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| stoichiometry |
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| the study of the quantitative, or measurable relationships that exist in chemical formulars and chemical reactions |
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| coefficients |
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| in a balanced equation they indicate the number of particles of each substance taking part in the reaction |
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| mole-mole problems |
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converting from moles of one substance to moles of another |
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| categories of stoichiometry problems |
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mass-mass mass-volume volume-volume |
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mass-mass problem and steps involved |
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you are given the mass of one substance to find the mass of another substance involved in the same reaction.
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mass-volume problems and steps involved |
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given the mass and asked to find the volume of a gas
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| volume-volume problems |
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like mole-mole problems, given a volume asked to find the unknown volume
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| stoichiometric proportions |
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qhen quantities of reactants are available in the exact ratio described by the balanced equation
means no reactants will be left over! |
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| the quantities of products formed in a reaction is determined by? |
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| the quantity of limiting reactant |
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| expected yield |
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| the amount of product that should be produced based on calculations |
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| actual yield |
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| the amount of a product that is really obtained from a chemical reaction |
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| percent yield |
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| what percent of the expected yield was acutally obtained to find: divide the actual over expected yield and multiply by 100% |
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| thermochemistry |
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| the study of the changes in heat in chemical reactions |
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| exothermic reaction |
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| reaction that releases heat |
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| endothermic reaction |
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| reaction that absorbs heat |
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| enthalpy |
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| the heat absorbed or released in a reaction depends on the difference in quantity of _____ |
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| standard enthalpy change |
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| an enthalpy change that is measured when reactants in their standard states change to products in their standard states |
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| Hess's law |
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| states that if a series of reactions are added together, the enthalpy change for the reaction will be the sum of the enthalpy changes for the individual steps |
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| heat of fusion |
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| the enthalpy change for the melting of ice |
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| heat of vaporization |
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| the enthalpy change for the vaporization of water |
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| calorimetry |
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| the study of heat flow and heat measurement |
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| heat capacity |
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| the amount of heat needed to raise the temperature of the object by 1 celsius degree |
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| specific heat |
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| the heat capacity of 1 gram of a substance |
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| 4.184 J/g x C |
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| the specific heat of liquid water |
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| heat |
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| the transfer of kinetic energy from a hotter object to a colder object |
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| condensed states |
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| liquids and solids are referred to this because substances in these states have substantially higher densities than they do in the gaseous state |
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| intermolecular forces |
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| the forces of attraction between neighboring molecules |
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| intramolecular |
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| forces that exist inside the molecule; covalent bonds consist of them |
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| induced dipole |
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| a dipole that is created by the presence of a neighboring dipole |
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| dispersion force |
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| when dipoles are induced and their is a negative end of the dipole of one atom being next to the positive end of another dipole. |
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| dipole-dipole forces |
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| attractions between opposite charges of neighboring dipoles |
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| viscosity |
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| the friction or resistance to motion, that exists between the molecules of a liquid when they move past each other |
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| surface tension |
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| the imbalance of forces at the surface of a liquid results in a property |
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| crystalline solid |
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| a solid in whihc the representative particles ezist ina highly ordered repeating pattern |
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| unit cell |
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| a minimal, repeating unit. as small as possible while accurately representing the pattern |
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| amorphous solids |
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| substances that are rigid and appear solid but do not behave like crystaline solids. |
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| covalent-network solids |
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| the covalent bornds form a network extending throughout the solid crystal whihc have high melting points correponding to the breaking of strong covalent bonds |
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| phase change/change of state |
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| the conversion of a substance from one of the three physical states of matter to another. there is always a change in energy. |
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| vaporization |
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| the change of state from liquid to gas |
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| condensation |
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| chage of state from gas to liquid |
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| evaporation |
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| the process by which molecules of a liquid escape from the surface of the liquid and enter the gas phase |
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| equilibrium vapor pressu |
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| pressure exerted by a vapor in equilibrium with its liquid; point at which the number of molecules in the vapor state remains constant |
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| boiling point |
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| the temperature at which the vapor pressure of a liquid becomes equal to the atmospheric pressure |
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| heat of vaporization |
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| the amount of heat necessary to vaporize a given amount of a liquid at its boiling point |
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| freezing point |
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| the temperature at which the solid and liquid forms of a substance exist in equilibrium |
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| heat of fusion |
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| the heat that is necessary to convert a given amount of a solid into a liquid |
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| sublimation |
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| the conversion of a solid directly to a gas |
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| deposition |
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| the reverse transformation of a gas directly into a solid |
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| heating curve |
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| a plot of the temperature of a sample as a function of time. |
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| phase diagram |
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| relates the states of a substance to temperature and pressure |
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| solution |
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| homogenous mixture of two or more substances in a single physical state |
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| particles |
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| atoms, molecules or ions evenly distributed in a solution or intermingled on the molecular level will NOT seperate |
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| solute |
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| the substance that is dissolved |
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| soluvent |
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| the substance that does the dissolving |
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| soluble |
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| a substance that dissolves in another substance |
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| insoluble |
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| a substance that doesn't dissolve in another |
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| alloys |
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| the most common solid solutions that contain two or more metals. They have greater strength, greater resistance to corrosion, and higher melting points that the pure elements from which they are made |
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| miscible |
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| pairs of liquids that can mix in all proportions. (water and ethanol) |
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| immiscible |
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| liquids that cannot mix in any propotions. (water and oil) |
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| aqueous solution |
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| solutions with water as the solvent |
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| electrolyte |
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| a substance that dissolves in water to form a solution that conducts an electric current |
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| concentrated solution |
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| contains a large amount of solute for the amount of solvent |
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| dilute solutions |
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| relatively small amount of solute for the amount of solvent |
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| concentration |
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| the amount of solute ina given amount of solvent or solution. Measured in molarity, molality, and mole fraction. |
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| molarity |
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| number of moles of solute dissolved in each liter of solution |
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| volumetric flask |
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| the best container for making a solution of a precise molarity |
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| molality |
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| the number of moles of solute dissolved in each kilogram of solvent |
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| mole fraction |
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| the number of moles of one component divided by the total number of moles in the solution. |
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| saturated |
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| a solution is _____when it contains as much solute as can possibly be dissolved under the existing conditions of temperature and pressure |
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| unsaturated |
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| a solution that has less than the mazimum amount of solute that can be dissolved |
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| supersaturated |
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| a solution that contains a greater amount of solute than that needed to form a saturated solution. These solutions are very unstable and do not stay this way for a long time. |
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| solvation |
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| the interaction between solute and solvent particles |
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| hydration |
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| the interaction between solute and solvent particles when the solvent is water |
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| solubility |
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| the amount of a solute that will dissolve in a specific solvent under given conditions. |
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| dipole |
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| seperation of charge |
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| polar solvent |
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| a liquid made up of polar molecules |
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| nonpolar solvent |
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| a liquid made up of nonpolar molecules |
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| henry's law |
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| the solubility of a gas is proportional to the partial pressure of the gas above the liquid |
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| surface area (dissolving) |
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| the dissolving of a solid solute takes place here. Solvent particles pull particles form the surgace of the solute into the solution. This can be speeded up by increasing this. |
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| stirring (dissolving) |
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| a technique frequently used to speed up the solution process. It moves the heavy concentration of dissolved solute away from the surface of the undissolved solute and makes fresh solvent.Basically, contact betwwen the solvent and the solute surface is increased. |
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| temperature (dissolving) |
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| raising this of a solvent increases the rate at which the solute dissolves because solvent particles move faster and more particles come into contact with the solute. Also the solvent particles have more energy to remove particles from the solid solution |
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| colligative property |
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| a property that depeneds on the concentration of solute particles but is independent of their nature. |
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| the four colligative properties |
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| vapor pressure reduction, boiling point elevation, freezing point depression, and osmotic pressure |
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| vapor pressure reduction |
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| the pressure of the vapor over a solvent is reduced when a nonvolatile solute is dissolved in the solvent. Directly related to the concentration of a solution. |
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| osmotic pressure |
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| pressure required to prevent osmosis. happens when the flow of solvent particles from a dilute solution to a concentrated solution across a semipermeable membrane results in uneven heights of the solutions on either side of the membrane. |
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| freezing point depression |
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| property in whihc the freezing point of a solvent is lowered when a nonvolutile solute is dissolved in the solvent. related to concentration of solution |
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| boiling point elevation |
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| boiling point of a solvent is raised when a nonvolatile solute is dissolved in the solvent. related to the concentration of a solution. |
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| isotonic |
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| solutions with identical osmotic pressure. no osmosis |
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| hypotonic |
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| when one solution has a lower osmotic pressure than the other. placing cells in this causes water to move into the cells causing the cells to burst. |
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| hypertonic |
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| when one solution has a higher osmotic pressure. a cell in this has water leave the cells causing the cells to shrivel and die, shrinking |
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| reversible reactions |
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| The chemical reaction in whihc the products can regenerate the original reactants |
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| chemical equilibrium |
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| the rate of the forward reaction is equal to the rate of the reverse reaction. It is the state whihc the concentrations of reactants and products remain constant with time because the rate at whihc they are formed in each reaction equals the rate at which they are consumed in the opposite reaction |
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| law of mass action |
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| expresses the relative concentartions of reactants and products at equilibrum in term of the equilibrium constant |
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| equilibrium constant |
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| Keq is a measure of the extent to whihc a reaction proceeds to completion |
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| equilibrium expression |
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| keq = products of FR/reactants |
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| law of chemical equilibrium |
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| every reversible reaction proceeds to an equilibrium state that has a specific ratio of the concentrations of reacts and products |
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| equilibrium position |
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| depends on the initial concentrations, each set of equilibrium concentrations |
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| homogeneous equilibria |
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| equilibrium conditions for reactions in which all the reactant and products are in the same state |
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| heterogenous equilibria |
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| equilibrium conditions for reactions that involve substances in more than one state |
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| the reaction quotient |
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| Q is used to find our if a reaction is at equilibrium. The concentrations that exist at the time the measurement is taken, not the equilibrium concentrations |
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| le chatelier's principle |
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| if a change in conditions is imposed on a system at equilibrium the equilibrium position will shift in the direction tends to reduce that change in conditions |
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| Q < Keq |
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| shifts to the right |
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| Q > Keq |
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| shifts to the left |
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| haber process |
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| an industrial process in which ammonia is synthesized. uses le chateliers principle to maximize the yield of ammonia |
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| dissolution |
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| the process in which an ionic solid dissolves in a polar liquid |
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| precipitation |
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| the process in which ions leave a solution and regenerate an ionic solid |
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| solubility equilibrium |
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| when dissolution and precipitation occur at the same rate and the saturated solutions of ions and the remaining solid are in chemical equilibrium. |
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| solubility product |
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| Ksp |
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| ion product |
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| Q is used to compare the solubility product to determine if an aqueous solution of ions is supersaturated and will form a precipitate. |
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| precipitation reactions |
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| a reaction in which two solutions are mixed and a precipitate form. described by balanced equations |
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| sparingly soluble substance |
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| insoluble |
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| complete ionic equation |
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| an equation that shows all soluble ionic substances as ions |
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| spectator ions |
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| ions that do not take part in a chemical reaction and are found in solution both before and after the reaction. |
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| net ionic equation |
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| only those compounds and ions that undergo a chemical change in a reaction in an aqueous solution |
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| common-ion effect |
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| a shift in equilibrium that occurs because the concentration of an ion that is part of the equilibrium has changed |
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| indicator |
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| a substance that turns one color in an acidic solution and another color in a basic solution |
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| neutralization reaction |
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| the reaction between an acid and a base, where the acid neutralizes the base and vise versa |
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| hydronium ion |
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| H3O + the complex an H+ ion forms with water |
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| amphoteric |
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| a substance such as water that can act as either an acid or a base depending on the circumstances |
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| conjugate acid |
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| when a base gains an H+ ion it becomes this |
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| conjugate base |
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| when an acid loses an H+ ion it becomes this |
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| the acid dissociation constant |
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| Ka the measure of the strength of an acid the greater the stronger it is |
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| base dissacoiation constant |
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| the strength of a base Kb |
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| salt hydrolysis reactions |
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| the reactions of ions from salts to form H3O+ or OH -1 ions |
