Question 1: Define 'surface area' in the context of chemical reactions.

Answer: Surface area refers to the total area of the exposed surface of a solid object that is available for reaction.

Question 2: Explain why increasing the surface area of a reactant generally increases the reaction rate.

Answer: Increasing the surface area provides more exposed particles for collisions, leading to a higher frequency of successful collisions and thus increasing the reaction rate.

Question 3: Describe how the surface area of a piece of aluminium foil compares to that of a solid aluminium block of the same mass.

Answer: The aluminium foil has a larger surface area because it is spread out into many thin layers, whereas the solid block has a smaller total surface area.

Question 1: A cube of sulphur has an edge length of 2 cm. Calculate its surface area in square centimetres.

Answer: Surface area = 6 × (edge length)^2 = 6 × (2)^2 = 6 × 4 = 24 cm²

Question 2: If the surface area of a powdered reactant is increased from 50 cm² to 150 cm², by what factor does the surface area increase?

Answer: Increase factor = 150 / 50 = 3

Question 3: A reaction is observed to double in rate when the surface area of the reactant is increased three times. Explain why this might not always be a linear relationship in real reactions.

Answer: In real reactions, factors such as particle size distribution, diffusion limitations, and other variables can cause deviations from a purely linear relationship between surface area and reaction rate.

Question 1: Describe a simple experimental setup to investigate how surface area affects the rate of a reaction between marble chips and hydrochloric acid.

Answer: Use different sizes of marble chips (e.g., large chunks, crushed powder) placed in identical containers with the same concentration and volume of hydrochloric acid. Measure the time taken for the reaction to complete or for a set amount of gas to be released. Keep variables such as temperature and concentration constant. Record and compare the reaction times to analyse the effect of surface area.

Question 2: Identify two safety precautions that should be taken when handling powdered chemicals in experiments involving surface area.

Answer: Wear safety goggles and a dust mask to prevent inhalation of powders; handle chemicals in a well-ventilated area to avoid inhalation of harmful fumes.

Question 1: A manufacturer powders a solid catalyst to increase its surface area. Explain how this change can improve industrial reaction efficiency.

Answer: Powdering increases the catalyst's surface area, providing more active sites for reactions, which enhances the rate of reaction and improves efficiency in industrial processes like catalytic converters.

Question 2: In the context of food preparation, how does increasing the surface area of ingredients (e.g., grinding spices) affect the flavour release?

Answer: Increasing surface area exposes more of the ingredient to the surrounding environment, allowing for faster and more intense flavour release.

Question 3: Discuss how the concept of surface area is relevant in the design of battery electrodes.

Answer: Battery electrodes are designed with maximised surface area (e.g., porous structures, nanomaterials) to increase contact with the electrolyte. This enhances ion exchange and improves the battery's charge and discharge rates, leading to better performance.