GRADE 8 NATURAL SCIENCE TERM 2 TOPIC TESTS AND MEMOS

 Atoms Test 1

 Question 1: 

Give the definitions for the following:

1. .

1.1. Atoms (2)

1.2. element (2)

1.3. Molecules (4)

1.4. Diatomic molecule (2)

1.5. Subatomic particle (2)

1.6. connection (3)

1.7. Electrolysis (3)

1.8. Decomposition reaction (3)

1.9. Blends (3)

 

Question 2:

2. .

2.1. What are the vertical columns in the periodic table called? (1)

2.2. What are the horizontal rows in the periodic table called? (1)

2.3. What is the first group on the periodic table called? (1)

2.4. What is the last group on the periodic table called? (1)

Atoms Test 2:

Question 1:

 1.1. How do atoms of different elements differ from each other? (2)

1.2. Name the 3 subatomic particles. (3)

1.3. What is the central part of the atom known as and what subatomic particles is the part made up of? (3)

1.4. What do we call the particles found in the nucleus (a single term.) (1)

Question 2:

2. ..

2.1. Which subatomic particles are responsible for the mass of the atom? (2)

2.2. Which subatomic particle is responsible for the volume of an atom? (1)

Question 3:

Indicate whether the following substances are pure, compound, or mixture.

Substance Pure substance, a compound and/or a mixture (State whether the mixture is homogeneous or heterogeneous)

3.1 Water

3.2 Seawater

3.3 Coffee (with milk and sugar)

3.4 Mayonnaise

3.5 Stainless steel

3.6 Iron hammers in sand

3.7 Air                                                                                                                                                  (13)

 

Particle Model Test 1:

Question 1:

Give a general summary of the behavior of particles of matter.                                                 (6)

Question 2:

Apply the motion theory in question 1 to a solid substance.                                                       (6)

Question 3:

Which processes in the body will make use of diffusion. Name 2.                                             (2)

Question 4:

Describe the process of diffusion if you pour green soda syrup into a glass of water.                (6)

                                      MEMORANDUM

Atoms Test Memorandum 1:

 

Question 1:

1. .

1.1. Atoms are the smallest building blocks of matter. (2)

1.2. An element is a substance that only consists of one type of atom. (2)

1.3. A molecule is composed of 2 or more atoms of the same or different elements. (4)

1.4. A diatomic molecule consists of two atoms of the same element. (2)

1.5. Subatomic particles are the particles found in an atom. (2)

1.6. A compound is a substance that consists of atoms of two or more elements. (3)

1.7. Electrolysis is the process where a compound is broken down by electricity. (3)

1.8. A decomposition reaction is a chemical reaction where a substance is broken down into smaller compounds or atoms. (3)

1.9. Mixtures are an impure substance that consists of two or more pure substances. (3)

 

Question 2:

2. .

2.1. Groups. (1)

2.2. Periods. (1)

2.3. Alkali metals. (1)

2.4. noble gases (1)

 

Atomic Memorandum 2:

Question 1:

1. .

1.1. Size and mass. (2)

1.2. Protons, neutrons and electrons. (3)

1.3. Nucleus, Protons and Neutrons. (3)

1.4. Nucleons (1)

 

Question 2:

2. .

2.1. Protons and neutrons (or nucleons). (2)

2.2. Electrons (1)

 

Question 3:

 

Substance Pure substance, a compound and/or a mixture (State whether the mixture is homogeneous or heterogeneous)

3.1 Distilled Water- Pure substance, compound

3.2 Seawater -Mixture, heterogeneous

3.3 Coffee (with milk and sugar) Mix- homogeneously

3.4 Mayonnaise -Mixture, heterogeneous

3.5 Stainless Steel Connection

3.5 Iron mortar in sand -Mixture, homogeneous

3.7 Air- Mixture, heterogeneous                                                                            (13)

                                                                                                        

Particle Model Memorandum 1:

Question 1:

1.1        Matter consists of particles.

1.2        Particles are constantly moving.

1.3        There are spaces between the particles.

1.4        Attractive and repulsive forces occur.

1.5        Collisions against each other and against the walls of the container.

1.6        Temperature and kinetic energy of particles are directly proportional to each other.    (6)

 

Question 2: 

2.1   Matter consists of particles.

2.2   Particles vibrate.

2.3   There are very small spaces between the particles.

2.4   Attractive forces are very strong and repulsive forces are overcome.

2.5   Particles take the shape of the container.

2.6   Temperature and kinetic energy of particles are directly proportional to each other and in this case low.                                                                                                                                                     (6)

 Question 3 

3.1   Breathing.

3.2   Digestion in the stomach etc.                                                                                                            (2)

Question 4:

At first there will be clear streams of green soda visible in the water. The currents will become lighter and spread out. As the particles collide, the soft drink syrup will move from a high concentration to a low concentration until the soft drink is a homogeneous green.                                                              (6)