Сформулируйте вопросы на английском языке и дайте ответы на них. Что такое теплоемкость?
What is the heat capacity?
The heat capacity of a defined system is the amount of heat needed to raise the system's temperature by one degree. It is expressed in units of thermal energy per degree temperature. To aid in the analysis of systems having certain specific dimensions, molar heat capacity and specific heat capacity can be used.
Molar Heat Capacity
The amount of heat needed to increase the temperature of one mole of a substance by one degree is the molar heat capacity. It is expressed in joules per moles per degrees Celsius (or Kelvin), Joules/Moles∘C (K).
Specific Heat Capacity
The amount of heat needed to increase the temperature of one gram of a substance by one degree is the specific heat capacity. It is expressed in joules per gram per degree Celsius, Joules/Grams∘C.
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.