Changing the surface area of the reactants

State what happens to the rate of reaction when a solid reactant is broken into smaller pieces, keeping all other conditions the same.

A student compares the reaction between calcium carbonate and hydrochloric acid using two forms of calcium carbonate: large lumps and powdered. All other conditions are kept the same.

Two pieces of magnesium ribbon, A and B, have the same mass. Ribbon B is cut into 4 equal shorter pieces. Both are added to separate beakers with the same volume and concentration of hydrochloric acid at the same temperature.

Ribbon A takes 200 seconds to finish reacting. Estimate how the time taken for Ribbon B to finish reacting compares to A, and explain your reasoning.

Explain why a reaction between a solid and a liquid is faster when the solid is ground into a fine powder rather than used as one large lump.

The graph below shows how the mass of carbon dioxide produced changes over time during the reaction between excess hydrochloric acid and two forms of calcium carbonate, both of the same mass.

Complete the sentence: Reactions between a solid and a liquid are faster when the solid has a ________ surface area.

Iron filings (very small pieces) and an iron nail (large piece) are both placed separately into dilute sulfuric acid. The mass of each iron sample is the same.

A reaction between a solid and a liquid produced 32 cm³ of gas in 4 minutes. When the same mass of solid is powdered and reacted in the same conditions, the reaction is complete in 2 minutes. Calculate the average rate of gas production in both cases. Give your answers in cm³/min and compare the results.

A student reacts powdered calcium carbonate with dilute hydrochloric acid. Explain why the reaction happens faster than if the same mass of calcium carbonate is in large lumps, not powder.

Solid magnesium ribbon reacts with dilute sulfuric acid to produce hydrogen gas. A student wants to investigate how changing the surface area of magnesium affects the rate of reaction.