Chem 15 – Chemistry – Flashcards
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| Accuracy |
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| the closeness of a measurement to the true value of the quantity that is measured. |
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| Actual Yield |
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| The amount of product actually obtained in a reaction |
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| Anion |
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| An ion with a negative charge |
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| Atom |
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| The smallest piece of an element that can enter into chemical combinations. |
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| Bronsted Acid |
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| A substance capable of donating a proton (H+) |
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| Bronsted Base |
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| A substance capable of accepting a proton. |
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| Catalyst |
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| A substance that increases the rate of a chemical reaction without itself being consumed |
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| Chemical Kinetics |
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| The area of chemistry concerned with the speeds, or rates, at which chemical reactions occur. |
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| Cation |
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| An ion with a net positive charge |
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| Compound |
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| A substance composed of atoms of two or more elements chemically united in fixed proportions |
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| Covalent bond |
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| A bond in which two electrons are shared by two atoms. |
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| Density |
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| the mass of a substance divided by its volume. |
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| Diffusion |
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| The gradual mixing of one substance with another due to random molecular motion. |
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| Dilution |
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| A procedure for preparing a less concentrated solution from a more concentrated solution. |
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| Electrolyte |
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| A substance that, when dissolved in water, results in a solution that can conduct electricity. |
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| Electronegativity |
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| The ability of an atom to attract electrons toward itself in a chemical bond. |
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| Element |
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| A substance that cannot be separated into simpler substances by chemical means. |
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| Endothermic Processes |
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| Processes that absorb heat from the surroundings. |
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| Energy |
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| The capcity to do work or to produce change. |
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| Enzyme |
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| A biological catalyst |
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| Equilibrium |
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| A state in which there are no observable changes as time goes by. |
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| Excess reagents |
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| One ore more reactants present in quantities greater than those needed to react with the quantity of the limiting reagent. |
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| Exothermic processes |
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| Processes that give off heat to the surroundings. |
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| First Law of Thermodynamics |
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| Energy can be converted from one form to another, but cannot be created or destroyed. |
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| Heat |
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| The transfer of thermal energy (energy associated with trandom motion of atoms and molecules) between two bodies that are at different temperatures. |
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| Hess's Law |
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| When reactants are converted to products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps. |
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| Hydrogen bond |
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| A special type of dipole-dipole interaction between containing hydrogen bonded to an electronegative element. The most important examples involve nitrogen, oxygen and fluorine. For instance, the attraction on one water molecule and the oxygen atom on a second water molecule would constitute a "hydrogen bond" |
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| Inorganic compounds |
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| Compounds other than organic compounds |
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| Ion |
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| A charged species |
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| Ionic bond |
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| The electrostatic force that holds ions together in an ionic compound |
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| Ionization energy |
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| The minimum energy required to remove an electron from an isolated atom (or an ion) in its ground state. |
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| Isotopes |
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| Atoms having the same number of protons but different numbers of neutrons. |
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| Joule |
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| Unit of energy given by newtons - meters. |
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| Kinetic energy |
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| Energy available because of the motion of an object. |
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| Le Chatelier's Principle |
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| If an external stress is applied to a system at equilibrium, the system will adjust itself in such a way as to partially offset the stress. |
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| Limiting reagent |
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| The reactant used up first in a reaction. |
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| Macroscopic Properties |
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| Properties that can be measured directly |
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| Metals |
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| Elements that are good conductors of heat and electricity and have the tendency to form positive ions in ionic compounds. |
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| Mixture |
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| A combination of two or more substances in which the substances retain their identity. |
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| Molar mass |
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| The mass of one mole of atoms, molecules, or other particles. |
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| Molarity |
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| The number of moles of solute in one liter of solution. |
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| MOle |
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| A collection of Avogadro's number of objects. |
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| MOlecule |
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| A neutral aggregate of two or more atoms held together by covalent bonds. |
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| Nonelectrolyte |
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| A substance that, when dissolved in water, gives a solution that is not electrically conducting. |
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| Octet rule |
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| An atom other than hydrogen tends to form bonds until it is surrounded by eight valence electrons. |
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| Percent yield |
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| The ratio of actual yield to theoretical yield, multiplied by 100%. |
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| pH |
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| The negative logarithm of the hydrogen ion concentration. |
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| Photon |
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| A particle of light. |
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| Physical property |
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| Any property of a substance that can be observed without transforming the substance into some other substance. |
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| Polar molecule |
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| Any molecule that possesses a dipole moment. |
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| Potential energy |
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| Energy available by virtue of an object's position. |
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| Precipitate |
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| An insoluble solid that separates from the solution. |
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| Precision |
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| The closeness of agreement of two or more measurements of the same quantity. |
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| Pressure |
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| Force applied per unit area. |
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| Salt |
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| An ionic compound made up of a cation and an anion. |
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| Saturated solution |
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| At a given temperature, the solution taht results when the maximum amount of a substance dissolves in a solvent. |
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| Significant figures |
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| The number of meaningful digits in a measured or calculated quantity. |
