Discuss how work done on a system or by a system affects the emerge of the system. Discuss how work done on the surroundings causes energy to be expended . Use example of work done during sublimation of dry ice which requires to be transferred as heat to the system from the surrounding. Discuss why energy balance exists. Introduce the formula u=q + w and define all terms. This represents a mathematical statement of Newton's first law of thermodynamics.
Review that the heat of reaction is due to the sum of the heats of formation of the products minus the heats of formation of the reactants. Continue with example to be calculated from last week, then determine the heat of reaction for the combustion of benzene.
Continue with heat of formation calculation. Use heat of formation equals the sum of the heat od the products minus the heat of the reactants. Solve in class the determination of he heat of formation when benzene undergoes combustion with oxygen.
Begin a discussion of Newton's 1st law of thermodytnamics which involves energy transferred as heat and work
Discuss the thermodynamics of the heat of fusion. Define heat of fusion and molar heat of fusion. Distinguish between the positive and negative results, between endothermic and exothermic results. Show examples of how to calculate the heat of formation of a chemical reaction, use the formula that the heat of formation is determined by subtracting the heat of products from the heat of reactants using a balanced equation. Solve example problems
Define enthalpy as a thermodynamic quantity. Explain delta H terminology in terms of molar compounds, and standard temperature and pressure. Use several examples and examine the table of standard enthalpies of formation. Determine that most delta H results are negative which indicates that the formation of a compound from elements is usually an exothermic reaction. Decomposition of a compound results in heat usually absorbed. Note the zero results for certain elements and ions.
Assignment
Text questions
Session Minutes
45
Minutes Student Attended
45
Lesson Comments
Joshua was participating in the SAT during this time
Review and discuss heat of fusion and heat of vaporization. Calculate the heat of fusion and heat of vaporization involved in converting a given amount of ice into liquid and then into a vapor. Introduce a problem, write and discuss the steps needed to solve, present required heats for each step and calculate the heat energy required. Use the formula q1 + q2 +q3 .....= total heat of the system.
Lab exercise to determine the specific heat of a metal. The specific heat is calculated by first finding the heat transfer from the metal to. given amount of water using a styrofoam calorimeter.
