Chemistry Exam 2 Study Guide PDF

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Chemistry Exam 2 Study Guide (Chapters 5-7) Chapter 5: Chemical Reactions and Equations 5.1 What is a Chemical Reaction:  Reactant- a substance converted into another substance during a chemical reaction.  Product- a substance formed from another substance or substances during a chemical reaction. o Products are different from reactants in the arrangement of their component atoms. 5.2 How Do We Know a Chemical Reaction Occurs:  The clues most often used by chemists are the following: o Change in color o Production of light o Formation of a solid (such as a precipitate in solution, smoke in air, or a metal coating) o Formation of a gas (bubbles in solution or fumes in the gaseous state) o Absorption or release of heat (sometimes appearing as a flame) 5.3 Writing Chemical Equations:  Chemical Equation- an abbreviated representation of a chemical reaction consisting of chemical symbols and formulas.  Balanced Equation- a chemical equation that uses coefficients in front of each formula to make the number of atoms of each element the same on both sides of the equation.

5.4 Predicting Chemical Reactions: Classes of Chemical Reactions

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Decomposition Reaction- a chemical reaction in which a substance breaks down into simpler compounds or elements.

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Anhydrous- a compound free of molecular water. Combination Reaction- a reaction in which two elements, an element and a compound, or two compounds join to form a new compound.

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Single-Displacement Reaction- a reaction in which a free element displaces another element from a compound to produce a different compound and a different free element.

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Corrosion- a slow deterioration of metals due to interaction with the environment. Double-Displacement Reaction- a reaction in which two compounds exchange ions or elements to form new compounds.

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Precipitation Reaction- a reaction in which the reactants in solution exchange ions to form a solid. o Precipitate- an insoluble solid deposited from a solution. Neutralization Reaction- a reaction of an acid and a base to form an ionic compound and water.

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Combustion Reaction- a reaction that involves oxygen molecules as a reactant and that rapidly produces heat and flames.

Rules Used to Predict the Solubility of Ionic Compounds

5.5 Representing Reactions in Aqueous Solution:  Molecular Equation- a form of a chemical equation in which substances are represented as it they existed as molecules, even though the substance may exist in solution as ions.  Ionic Equation- a form of a chemical equation in which ionic species are represented as the separated ions.  Spectator Ions- an ion that is not involved in a chemical reaction.  Net Ionic Equation- a form of a chemical equation in which ionic compounds are represented as the separated ions, and spectator ions are eliminated.

Chapter 6: Quantities in Chemical Reactions

6.1 The Meaning of a Balanced Equation Relationships Between Reactants and Products

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Stoichiometry- the use of quantitative relationships between substances involved in a chemical reaction to determine the amount of a reactant or product.

6.2 Mole-Mole Conversions  Mole ratios are obtained from the coefficients in a balanced equation.

6.3 Mass-Mass Conversions

Example:

6.4 Limiting Reactants  Limiting Reactant- the reactant that is completely used up in the reaction and therefore determines the amount of other reactants that react and the amount of products that should form.

6.5 Percent Yield  Theoretical Yield- the maximum amount of product that can be obtained in a chemical reaction from known amounts of reactants; the amount of product calculated by assuming all the limiting reactant is consumed.  Actual Yield- the amount of product actually obtained in the laboratory from a reaction.  Percent Yield- the ratio of the amount of product actually formed in a reaction to what is predicted by stoichiometry, multiplied by 100%.

6.6 Energy Changes  Exothermic Reaction- a chemical change that releases heat.  Endothermic Reaction- a chemical change that absorbs heat.

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Heat- the energy that is transferred between objects due to a difference in their temperatures. o 4.184 J = 1 cal o 1 Cal = 1000 cal Specific Heat- a property that is a measure of the amount of heat required to raise the temperature of 1 g of a substance by 1 degree C.

6.7 Heat Changes in Chemical Reactions

Chapter 7: Electron Structure of the Atom 7.3 The Modern Model of the Atom  Orbital- a three-dimensional region in space around a nucleus where an electron is likely to be found.

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Sublevel- an energy level consisting of only one type of orbital at a specific principal energy level; usually consisting of more than one orbital. Ground State- the state of lowest energy in an atom where the electrons occupy orbitals that are lowest in energy.

Hund’s Rule- a rule stating that electrons are distributed in a set of orbitals of identical energy in such a way as to give the maximum number of unpaired electrons.

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Principal Energy Level- an energy level containing a set of electrons in orbitals of similar sizes.

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Electron Configuration- a description of the distribution of electrons in atomic orbitals or sublevels.

7.4 Periodicity of Electron Configurations

7.5 Valence Electrons for the Main-Group Elements  Valence Level- the principal energy level that is highest in energy and contains the largest filled orbitals.  Valence Electron- an electron in the highest principal energy level, the valence level.  Core Electron- an electron in an atom that is not a valence electron; an inner electron.

7.6 Electron Configurations for Ions VS

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Isoelectronic- having the same number of electrons.

7.7 Periodic Properties of Atoms Reactivity  Alkali metals and alkaline earth metals are the most reactive metals. o The more easily metal atoms give up their valence electrons, the more reactive they are.  Because valence electrons are farthest from the nucleus, they’re the one that participate in chemical reactions.  Halogens are highly reactive nonmetals.  Ionization Energy- the minimum energy required to remove a valence electron from a gaseous atom or ion; usually reported in kJ/mol. o Atoms with low ionization energies do not bind their valence electrons very tightly, so they are very reactive.

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Atomic Radius- a measure of atomic size; the distance from the nucleus to the outer edge of the atom....