Q1-4: Charcoal is made of carbon. When charcoal burns, it combines with oxygen to make carbon dioxide.

1. Which row in this table correctly describes carbon and carbon dioxide?

2. Which of the following is the correct word equation for this reaction?

• A. carbon + oxygen → carbon dioxide
• B. carbon dioxide → carbon + oxygen
• C. carbon + carbon dioxide → oxygen
• D. carbon dioxide + oxygen → carbon

3. Carbon dioxide contains one carbon atom and two oxygen atoms as shown in the image.

Which of these is the correct formula for carbon dioxide?

• A. CO²
• B. CO2
• C. C2O
• D. CO₂

4. What is the name given to this type of reaction?

• A. Neutralisation reaction.
• B. Displacement reacton.
• C. Combustion.
• D. Thermal decomposition.

5-7: These questions are about table salt.

Table salt is made of two elements combined: Sodium and chlorine.

5. What is the correct chemical name for table salt?

• A. Sodium chlorine
• B. Sodium chloride
• C. Sodium chlorate
• D. Sodium chloroform.

? A B C D

6. Salts can be made when an acid and alkali react as shown here:

What is the name of substance X?

• A. water
• B. carbon dioxide
• C. sodium chlorine
• D. hydrogen gas

7. What is the name given to the reaction shown in question 6?

• A. Neutralisation reaction.
• B. Displacement reacton.
• C. Combustion.
• D. Thermal decomposition.

8-9. This iron chain has rusted in the open air.

8.Which of these sentences is true about the process of an iron chain rusting?

• A. The chain gets lighter as the iron reacts with oxygen in the air.
• B. The chain gets heavier as the iron reacts with oxygen in the air.
• C. The chain gets lighter as the iron reacts with nitrogen in the air.
• D. The chain gets heavier as the iron reacts with nitrogen in the air.

9. What is the name given to this kind of reaction?

• A. Neutralisation reaction.
• B. Displacement reacton.
• C. Oxidation.
• D. Combustion.