Chemistry 120 Objectives – Exam 2                                                 Spring 05

 

Gases

·        Use the ideal gas law to solve for an unknown quantity

·        Apply the general gas law to solve for an unknown quantity

·        Use the ideal gas law to determine the molar mass or the density of a gas

·        Calculate the partial pressure of a gas in a mixture and the total pressure of a gas mixture

·        Apply stoichiometry to problems involving gases

·        Apply Graham’s Law to determine the molar mass or rate of effusion of a gas

·        Calculate the root mean square velocity of molecules in a gas

·        Explain the origin of pressure in molecular terms

·        Know the assumptions of the Kinetic Molecular Theory

·        Apply the Kinetic Molecular Theory to explain relationships between P, V, T, and number of moles of a gas

·        Compare a real gas to an ideal gas: under what conditions do gases behave ideally and how does a real gas differ from the model of an ideal gas

·        Describe how the characteristics of a gas determine the value of a and b in the van der Waal’s equation

 

Thermochemistry

·        Use the First Law of Thermodynamics to relate the heat gain or lose, work , and change in energy of a system

·        Distinguish between DE and DH for a system

·        Relate exothermic or exothermic reactions to the sign of DH and direction of heat flow into or out of a system

·        State standard conditions for thermodynamics

·        Understand Hess’s Law and apply it to calculating the DH for a reaction

·        Use specific heat to calculate heat transferred or to determine the specific heat of a substance

·        Calculate enthalpy changes from calorimetry data

·        Write the equation for the standard enthalpy of formation of a substance

·        Use standard enthalpies of formation to calculate the enthalpy change for a reaction

·        Given DH for a reaction and standard enthalpies of formation for all substances except one calculate its standard enthalpy of formation

 

Equilibrium

·        Interpret chemical equilibrium as a dynamic process involving change at the molecular level

·        Write the equilibrium expression for a chemical reaction given a balanced equation

·        Calculate the effect on the value of K of reversing a reaction or multiplying the coefficients of a reaction by a constant.

·        Combine equations and their K values to obtain K for an overall reaction

·        Use the equation KP = (RT)DnKC to calculate either KP or KC given the other and a balanced chemical equation

·        Given the value of K for a chemical reaction predict whether the reaction will favor reactants or products (the position of the equilibrium)

·        Use Q to determine if a system is at equilibrium or which direction reaction will proceed to reach equilibrium

·        Perform calculations to determine concentrations at equilibrium or the value of the equilibrium constant

·        Use simplifying assumptions when appropriate

·        If necessary, stoichiometrically shift the reaction in order to solve an equilibrium problem

·        Apply Le Chatelier’s Principle to predict changes in an equilibrium system when there are changes in on of the following: concentration, pressure, volume, temperature