L esson 3 Exercise
1- Complete the following sentences:
a. Size of solute molecules in real solution is ...................than that in colloidal solution.
b. In................................... solution, solute molecules can be distinguished by the eye.
c. It is possible to dissolve more solute in the ................................... solution.
d. In the stomach, there is ................................... that help in the digestion of proteins
e. Solution can be classified in terms of homogeny into .........................&…………….
2- Write the scientific term that corresponds to each of the following:
a. A solution that accepts the dissolution of an additional amount of the solute in it with the increase in temperature.
b. A solution whose components can be separated by refining or filtration.
c. A solution in which solute molecules are distributed in solvent in irregular way.
d. A mixture that is homogenous in composition and properties and consists of two or more substances that are not chemically united.
e. A solution in which an additional amount of the solute can be added at a certain temperature.
3- Write one economical importance for each of the following:
a. Sulfuric acid.
b. Calcium hydroxide.
c. Calcium carbonates.
d. Magnesium hydroxide.
e. Sodium chloride.
f. Hydrochloric acid.
g. Enzymes in the human body.
4- Compare between each of the following:
a. Colloidal and suspension solutions.
b. Homogenous and non-homogenous solutions.
c. Saturated and unsaturated solutions.
d. Simple substitution and double substitution reactions.
e. Metal oxide and metal hydroxide beatings.
…………………………………………………………………………………...
c. Preservation of food in the freezer.
…………………………………………………………………………
Science, Technology and Society
1- The catalytic converter
Most modern cars are equipped with a catalytic converter that helps in the treatment of harmful gases. It is composed of ceramic cells similar to bee cells, but they are
covered with thin layer of a catalytic metal as platinum.
The idea of using this converter is based on the exposure of the largest part of the surface of the catalytic substance to the current of the emitted gases from the engine so as to economize the use of these.
2- Air bags الوسائد الهوائية
Car air bags are considered one of the most important safety means at emergencies. They are designed in a way that they get inflated at an extreme speed within only 40mm second on the occurrence of the car crash with another object. Then, they get vacuumed rapidly to ensure both the motorist’s clear vision and proper movement. This leads to the decomposition and explosion of sodium nitride forming sodium and nitrogen that fills the air bag on crashing.
2Na3N
6Na + 3N2
Sodium nitride sodium nitrogen
3- Usage of sodium bicarbonate in your life:
A) Shinning metal
● It is used in shining silver by using a piece of aluminium foil while washing.
● Any decorative metal pieces made of copper or chrome are rubbed with a cloth wet with water and immersed in sodium bicarbonate