Types of Reaction KS3

Which of the following best describes thermal decomposition?

• A reaction that absorbs heat and breaks down compounds
• A reaction that produces light without heat
• A reaction that creates new substances without breaking down existing ones
• A reaction that combines elements to form a compound

Which statement accurately describes the specificity of catalysts?

• Catalysts change the nature of the reactants.
• Catalysts are not needed for any reactions.
• One catalyst can work for all reactions.
• Different reactions require different catalysts.

How can you summarize the reaction of calcium carbonate with hydrochloric acid?

• Calcium carbonate + hydrochloric acid → calcium chloride + water + carbon dioxide
• Calcium carbonate + oxygen → calcium oxide + carbon dioxide
• Calcium chloride + water → calcium carbonate + hydrochloric acid
• Calcium carbonate + water → calcium chloride + carbon dioxide

What does the Law of Conservation of Mass state?

• The mass of reactants equals the mass of products
• Mass changes during a chemical reaction
• Mass is irrelevant in chemical reactions
• Mass can be created or destroyed in reactions

What is the result of burning wood in terms of mass conservation?

• The mass of the ashes is greater than the mass of the wood
• The mass of the wood and oxygen equals the mass of the gases produced
• The mass of the wood is lost during combustion
• The mass of the gases produced is less than the mass of the wood

In the example of burning wood, what is conserved according to the Law of Conservation of Mass?

• The mass of the gases produced is greater than the mass of the wood.
• The total mass of wood and oxygen equals the mass of ashes and gases produced.
• The mass of the oxygen only.
• The mass of the wood only.

How can the mass of steam produced from boiling water be measured?

• By weighing the pan before and after boiling.
• By measuring the temperature of the steam.
• By observing the amount of water left in the pan.
• By calculating the volume of steam produced.

What is combustion?

• A process that cools substances
• A reaction that produces light only
• A reaction where a fuel reacts with oxygen
• A process that creates new elements

Which of the following is essential for combustion to occur?

• Oxygen
• Nitrogen
• Carbon dioxide
• Water

How do combustion reactions benefit everyday life?

• They do not have any practical applications.
• They are used to cool homes.
• They generate electricity and heat homes.
• They are only used in laboratories.