39. Сформулируйте вопросы на английском языке и дайте ответы на них. Что такое внутренняя энергия?

What is the Internal Energy?

The internal energy of a system is identified with the random, disordered motion of molecules; the internal energy in a system includes potential and kinetic energy. This is contrast to external energy which is a function of the sample with respect to the outside environment (e.g. kinetic energy if the sample is moving or potential energy if the sample is at a height from the ground). The symbol for Internal Energy Change is ΔU.

Energy on a smaller scale:

• Internal energy includes energy on a microscopic scale

• It is the sum of all the microscopic energies such as:

• translational kinetic energy

• vibrational and rotational kinetic energy

• potential energy from intermolecular forces

Internal Energy Change Equations ΔU = Q+W, where Q is heat and W is work.

40. Сформулируйте вопросы на английском языке и дайте ответы на них. Что такое теплота?

What is Heat?

• The degree of hotness or coldness of a body or environment.

• A measure of the warmth or coldness of an object or substance with reference to some standard value.

• A measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees designated on a standard scale.

• A measure of the ability of a substance, or more generally of any physical system, to transfer heat energy to another physical system.

• Any of various standardized numerical measures of this ability, such as the Kelvin, Fahrenheit, and Celsius scale

The quantity of energy transferred as heat is a scalar expressed in an energy unit such as the joule (J), with a sign that is customarily positive when a transfer adds to the energy of a system. It can be measured by calorimetry.

• Heat gained is equal to heat lost

• Heat never flows from a cooler body to a hotter body of its own accord

• Heat can never be taken from a reservoir without something else happening to the system

41. 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.