Mastering Biology Chapter 2 – Flashcards
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The innermost electron shell of an atom can hold up to _____ electrons.
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2
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Do electrons determine the atoms size?
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Yes
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Radioactive decay is likely to occur when ...
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an atom has too many neutrons.
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What model most accurately represents the current view of the structure of the atom?
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Probability model
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A(n) _____ refers to two or more atoms held together by covalent bonds.
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molecule
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What name is given to the bond between water molecules?
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hydrogen
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Atoms with the same number of protons but with different electrical charges _____.
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are different ions
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In salt, what is the nature of the bond between sodium and chlorine?
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ionic
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An ionic bond involves _____.
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an attraction between ions of opposite charge
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What is the tendency for an atom to pull electrons toward itself?
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Electronegativity
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What correctly ranks the 4 main atoms in terms of decreasing electronegativity (the highest electronegativity first)?
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O, N, C, H
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Dr. Haxton says the O-O bond is polar and the C-C bond is nonpolar. A good student would say ...
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Wrong again, Ralph. Both bonds are nonpolar.
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Polar
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In molecules or bonds, the presence of distinct regions that have partial positive and negative charges.
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Polar covalent bond
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A type of covalent bond between atoms that differ in electronegativity. the shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
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Ionic bond
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A chemical bond resulting from the attraction between oppositely charged ions.
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Covalent bond
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A force that holds atoms together by a sharing of electrons
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Compared to covalent bonds, ionic bonds ...
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rely much less on electron-sharing.
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ion
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An atom that has gained or lost electrons, thus acquiring a charge.
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anion
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A negatively charged ion.
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cation
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An ion with a positive charge, produced by the loss os one or more electrons.
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ionization
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The process of producing ions.
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True or false: Ions may form by transferring an atomic nucleus (with or without electrons) to another molecule.
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True.
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A phrase that applies to covalent bonding and not other kinds of bonds is ...
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electron-sharing.
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polar attraction
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An attraction between polar molecules or between parts of a single polar molecule. Specifically, the attraction is between parts of molecules that bear opposite partial charges. Polar attractions are weaker than ionic forces because the charges are smaller.
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What statement about the following reaction is true? 4 Fe + 3 O2 → 2 Fe2O3
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Four atoms of Fe react with 3 molecules of O2 to form 2 molecules of Fe2O3
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Reaction equation
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An event that alters the covalent bonding between atoms. Chemical reactions convert old kinds of molecules into new kinds.
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Chemical equation
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A symbolic statement that summarizes a chemical reaction by listing the initial and final molecules, separated by an arrow indicating the direction of change. For example, the conversion of molecules A and B to C and D is summarized by the reaction equation A + B → C + D.
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Reactant
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A molecule that enters into a chemical reaction and is changed by the reaction.
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Product
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In a chemical reaction, a molecule that is made by the reaction.
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Coefficient
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In a chemical equation, coefficients are numbers that are written before chemical formulas to balance the equation. they indicate the proportions in which the substances take part in the reaction (in terms of formula units, molecules, or moles).
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Ammonia
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The compound NH3
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What's the appropriate balanced equation for the following chemical reaction. C6H6 + H2 → C6H12
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C6H6 + 3 H2 → C6H12
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What's the correct balanced equation for the following reaction. C8H18 + O2 → CO2 + H2O
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2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
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Activation energy
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The potential energy that reacting molecules must acquire to reach the transition state in a chemical reaction. Activation energy is usually acquired by conversion of kinetic energy to potential energy as molecules are distorted in a collision.
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Catalysts speed reactions mainly by ...
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lowering EA.
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Catalyst
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An agent the speeds a process (typically a chemical reaction) without being changed in the process and without altering the position of equilibrium. Among other effects, catalysts provide a new reaction pathway in which the steps have lower activation energy requirements than the uncatalyzed reaction. Most biological catalysts are proteins called enzymes.
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equilibrium
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In a reversible chemical reaction, chemical equilibrium is the point at which the rate of the reverse reaction.
