Сформулируйте вопросы на английском языке и дайте ответы на них. Сформулируйте первое начало термодинамики
Describe the First Law of Thermodynamics
The first law of thermodynamics is the application of the conservation of energy principle to heat and thermodynamic processes:
The first law makes use of the key concepts of internal energy, heat, and system work. The standard unit for all these quantities would be the joule, although they are sometimes expressed in calories.
It is typical for chemistry texts to write the first law as ΔU=Q+W. It is the same law, of course - the thermodynamic expression of the conservation of energy principle. It is just that W is defined as the work done on the system instead of work done by the system.
Сформулируйте вопросы на английском языке и дайте ответы на них. Какой процесс называется адиабатным? Изобарным? Изохорным? Изотермическим.
What is the adiabatic process? Isobaric, Isochoric, Isothermal
An adiabatic process is one in which no heat is gained or lost by the system. The first law of thermodynamics with Q=0 shows that all the change in internal energy is in the form of work done: ΔU= - W. ΔW equals the change in a physical property of the system. A physical property of the system depends only on the state of the system (P, V, T), not on the way the system was put into this state.
An isobaric process is a process that occurs at constant pressure. We then have W = P(V2 - V1). If the pressure of an ideal gas is kept constant, then the temperature must increase as the gas expands. (PV/T = constant). For an isobaric process we write ΔU = ΔQ - ΔW = ΔQ – P (V2 - V1).
An isochoric process takes place at constant volume. Then W = 0 and ΔU = ΔQ. All the heat added to the system goes into increasing its internal energy.
An isothermal process occurs at constant temperature. Since the internal energy of a gas is only a function of its temperature, ΔU = 0 for an isothermal process. Since ΔU = 0, the heat transferred to the gas is ΔQ = W.
Сформулируйте вопросы на английском языке и дайте ответы на них. Сформулируйте предположения молекулярной модели идеального газа.
Describe the molecular model for an ideal gas
Ideal gas: A theoretical gas composed of randomly moving non-interacting particles. At normal conditions such as standard temperature and pressure, most real gases behave qualitatively like an ideal gas.
Kinetic model of an ideal gas: A model which treats a gas as many molecules subject to the following assumptions:
· The molecules obey Newton’s laws
· The intermolecular forces are negligible
· The molecules are spherical with negligible volume
· The motion of the molecules is random
· The collisions are perfectly elastic
· The time taken for a collision is negligible.
The
ideal gas equation is:
or
Universal
Gas Constant:
Сформулируйте вопросы на английском языке и дайте ответы на них. Как записывается связь между давлением и кинетической энергией газов?
Describe relationship between pressure and molecular kinetic energy.
