States of Matter: Solids, Liquids and Gases

To understand he various states of matter and their connection to each other molecules, we must understand the meaning of the word molecule.

We can divide a piece of material into smaller parts and then subdivided each of these small parts into still smaller parts. We shall continue this process of division until the parts become very, very small. In the and they will become so small that it will be impossible to divide them further. We call these smallest particles atoms. They are the fundamental building blocks of all materials and they have a definite attraction for each other.

Atoms combine into molecules and molecules may contain one, two, three and more atoms. In metals there is only one atom in a molecule, for example.

The molecules of a solid are very close together and have a great attraction for each other. The closer they are together, the heavier is the solid; however, the molecules are in the state of continual vibration. In this state their attraction for each other is very great, and that is why it is very difficult to change the shape of a solid.

Now, if we heat the solid, the molecules begin to vibrate more and more and therefore there is less attraction for each other. Thus, a solid expands when we heat it. When the molecules are quite far apart from each other, the solid changes into a liquid.

If we continue to heat the liquid, the molecules begin to vibrate so strongly and they move so far apart form each other that they will have very little attraction for each other. Now the liquid becomes a gas which has no definite size.

The three states of matter - solid, liquid and gaseous - are very close to each other and more heat or less heat will change the substance from one state to the other. Ice, water and steam are examples of this change of state.

Statements:

1. To understand the various states of matter and their connection to each other we must understand the meaning of the word molecule. 2. Atoms are the fundamental building blocks of all materials and they have a definite attraction for each other. 3. Atoms combine into molecules and molecules may contain only two atoms. 4. If we heat a solid the molecules begin to vibrate more and more and therefore there is more attraction for each other. 5. When the molecules are quite far apart from each other the solid doesn't change to a liquid. 6. If we continue to heat the liquid the molecules begin to vibrate so strongly and they move so far apart from each other that they will have very little attraction for each other and the liquid becomes a gas without definite size.

 

 

Ключи к лабораторной работе 3:

Задание 1. Quantity - number; to call - to name; several - some; usually – commonly; within - in, for; rapidly - fast; various - different; therefore - that is why, since; shape - form; characteristic.

Задание 2. Определять – определенный – определение – неопределенный – неопределенно; существовать – существование; означать – значение, освобождать – свобода – свободный – свободно; газ – газообразный; равняться (приравнивать) – равенство – уравнение – в равной степени, одинаково, продолжать – продолжение – непрерывный – постоянный – постоянно, занимать – род занятий (профессия), завладения; содержать в себе (вмещать) – контейнер; сосуд – содержание; испарять – пар – испарение – выпаривать – выпаривание (парообразование), притягивать – притяжение – притягательный.

Задание 3, 1-14; 2-13; 3-12. 4-2; 5-10; 6-9; 7-15; 8-11, 9-4; 10-3; 11-6; 12-1; 13-8; 14-7;

15-5.

Задание 4. 1. Chemists produced a number of new elements by means of nuclear reactors. 2. Ukraine takes great care of scientists. 3. The molecules of gas are in a state of very rapid and continual motion. 4. The liquid state is between the gaseous and solid states. 5. The closer the molecules are together the less free they are to move.

Задание 5. 1-5; 2-3; 3-4; 4-5; 5-1.

Задание 6. 1-2, 2-3; 3-1; 4-5; 5-4.

Задание 7. I. It's wrong, 2. It's right; 3. It's wrong; 4. It's wrong, 5. It's right.

Задание 8. 1. We shall carry on a number of experiments with several gases. 2. In general, the gas molecules are free to move and they are quite far apart. 3. Both the structure of molecules and the structure of atoms are of great interest for the scientists. 4. The liquid state isn't the only state in which water can exist. 5. Mole - cules are the elements of which the physical world consists.

Задание 9. 1. It is true; 2. It is true; 3. It is false; 4. It is false; 5. It is false; 6. It is true.

 

 

Unit 3