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

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

Question 2: Explain how increasing the surface area of a reactant affects the rate of a chemical reaction.

Answer: Increasing the surface area exposes more particles to react, which generally speeds up the reaction rate.

Question 3: Which form of a solid reactant typically has the greatest surface area: a large block or crushed powder? Why?

Answer: Crushed powder has a greater surface area because crushing breaks the solid into many small particles, increasing exposed surface.

Question 4: Describe a practical experiment to demonstrate the effect of surface area on reaction rate, including safety precautions.

Answer: One experiment involves reacting aluminum foil with hydrochloric acid. Use small pieces and crushed powder separately in identical containers, observing reaction speed. Safety precautions include wearing gloves and goggles to handle acids and sharp foil.

Question 5: A student observes that powdered sulfur reacts faster with oxygen than a large lump of sulfur. Explain why.

Answer: Because the powdered sulfur has a larger surface area exposed to oxygen, increasing the reaction rate.

Question 6: Calculate the surface area to volume ratio for a cube of sulfur measuring 2 cm on each side. Use the formula: Surface Area / Volume.

Answer: Surface Area = 6 × (2 cm)^2 = 24 cm^2 Volume = (2 cm)^3 = 8 cm^3 Surface Area to Volume Ratio = 24 cm^2 / 8 cm^3 = 3 cm^-1

Question 7: In industrial processes, why is increasing the surface area of catalysts important?

Answer: Increasing surface area of catalysts provides more active sites for reactions, making processes more efficient and faster.

Question 8: Identify which of the following reactions would likely be faster: (a) rusting of a large iron sheet or (b) rusting of iron filings. Justify your answer.

Answer: B) Rusting of iron filings because the filings have greater surface area exposed to air and moisture.

Question 9: Fill in the blank: Increasing the surface area of a solid reactant generally _______ the rate of reaction.

Answer: increases

Question 10: Explain how surface area considerations are applied in the development of new cleaning products or industrial catalysts.

Answer: In cleaning products and catalysts, increasing surface area—such as using powders, porous materials, or nano-sized particles—enhances contact with dirt, stains, or reactants, resulting in faster and more efficient cleaning or chemical reactions. This optimization improves effectiveness and reduces reaction times in various industrial processes.