Question on unit 1

Lesson 2

I. Complete the following sentences:-

1. The molecule of magnesium element is composed of ...... atom(s), while themolecule of chlorine is composed of ...... atom(s).

2. Helium is considered from …………. and its molecule is composed of...... atom.

3. Substances in which their molecules are composed of two or more different elements in a definite ratio are known as......

4. ………..is a diatomic liquid element, while is a mono atomic liquid element.

5. Table salt is a compound that consists of ...... atom and …………… atom.

6. Ammonia molecule is composed of ...... atoms and one ……………… atom.

7. All solid molecules are ……………… molecules, while nitrogen gas molecules are ……………………

8. Iron molecule consists of ...... , while bromine molecule consists of......

9. Hydrogen molecule is composed of ...... atom(s), while argon molecule is composed of ...... atom.

10. Atoms are similar in the molecule of ...... , while they are different in the molecule of ……………..

11. The molecule of mercury consists of ...... atom, while the molecule of copper consists of ...... atom.

12. The liquid element which consists of one atom is …………, while that which consists of two atoms is......

II.Write the scientific term for each of the following:

  1. The building unit of matter.
  2. The smallest part of matter which can exist in a free state and keep theproperties of matter.
  3. A process in which solid molecules gain energy and convert into liquid one'
  4. A process in which liquid molecules gain energy and convert into gaseous one.
  5. Molecules that have very small intermolecular spaces and strong attraction forces'
  6. Molecules that have fast movement and take the shape of their containers.
  7. The spaces that found among the molecules of matter'
  8. The building unit of molecule'
  9. The simplest pure form of matter which can't be analyzed into simpler form.

10. The combination of two or more different elements.

III. Give reason for each of the following :

l. Disappearance of a little amount of table salt when it is put in a beaker containing water for a period of time.

2. It is easy to divide an amount of water into smaller parts.

3. The volume of a mixture of water and alcohol is less than the sum to their volumes before mixing.

4. The odour of perfume spreads all over the room when the bottle is opened.

5. It is difficult to break down a piece of iron with your hand.

6. The solid matter has a definite shape, while the liquid matter takes the shape of its container.

7. Water takes the shape of its container.

8. Iron and aluminum have fixed shapes.

9. When water gains energy, it converts into gas.

10. The properties of solid molecules differ from that of liquid molecules.

IV. Define each of the following:-

  1. The molecule.
  2. Melting process.
  3. Vaporization process.
  4. Element.
  5. Compound.

V. Explain what happens when you:-

  1. Open a perfume bottle in a closed room for a while.
  2. Heat a piece of solid matter for a long time.
  3. Add 50 cm3 of ethyl alcohol to 100 cm3 of water.
  4. Try to divide a piece of iron with your hand.
  5. Heat some water in a beaker to its boiling point.
  6. Put some table salt in a beaker containing water.

VI. Compare between solid, liquid and gases states related to:-

  1. The motion of the molecules.
  2. Intermolecular spaces.
  3. Shape.
  4. Intermolecular forces.