Physical chemistr Physical Chemistry Cheng Xuan February 2004, Spring Semester
1 Physical Chemistry Cheng Xuan February 2004, Spring Semester Physical Chemistry
Physical Chemistry Summary Ideal gases/Perfect gases Key Notes e Gases: a fluid which has no intrinsic shape and which e expands indefinitely to fill any container in which it is held The ideal gas equations: the relations among the amount of gas substance, temperature, pressure and volume PV=nRT PYm=RT Vm: molar gas volume
3 Key Notes Ideal Gases/Perfect Gases Physical Chemistry Summary Gases: a fluid which has no intrinsic shape, and which expands indefinitely to fill any container in which it is held. The ideal gas equations: the relations among the amount of gas substance, temperature, pressure and volume. PV = nRT PVm = RT Vm: molar gas volume
Physical Chemistry Summary Ideal gases/Perfect gases Key Notes e Partial pressure: the pressure exerted by each component In a gaseous mixture P=nrt/v n. mole irp total x;: mole fraction e Dalton's law: the total pressure exerted by a mixture of ideal gases in a volume is equal to the arithmetric sum of the partial pressures total niota rT/y
4 Key Notes Ideal Gases/Perfect Gases Physical Chemistry Summary Dalton’s law: the total pressure exerted by a mixture of ideal gases in a volume is equal to the arithmetric sum of the partial pressures. Ptotal = ntotalRT/V Partial pressure: the pressure exerted by each component in a gaseous mixture. Px = nxRT/V Pi = xiPtotal nx : mole xi : mole fraction
Physical Chemistry Chapter 2 CHAPTER 2 -. The First Law of Thermodynamics Basic Concepts Isothermal A system which is held at constant temperature Adiabatic: A system in which energy may be transferred as work but not as heat Diathermic: a system which allows energy to escape as heat through its boundary if there is a difference in temperature between the system and its surroundings
5 Isothermal: A system which is held at constant temperature Adiabatic: A system in which energy may be transferred as work, but not as heat. CHAPTER 2 The First Law of Thermodynamics Basic Concepts Diathermic: A system which allows energy to escape as heat through its boundary if there is a difference in temperature between the system and its surroundings. Physical Chemistry Chapter 2
Physical Chemistry Chapter 2 Interna l Energy Internal energy: Total amount of energy in a system. The sum total of all kinetic and potential energy within the system Internal energy changes: The sign of AU Negative values: a system loses energy to the surroundings Positive values: a system gains energy from the surroundings
6 Internal energy: Total amount of energy in a system. The sum total of all kinetic and potential energy within the system. Internal energy changes: The sign of U Negative values: a system loses energy to the surroundings Positive values: a system gains energy from the surroundings Physical Chemistry Chapter 2 Internal Energy