A student investigated the rate of the reaction that took place between a solution of HCl and the calcium carbonate (CaCO₃) in broken eggshell - Leaving Cert Chemistry - Question 7 - 2019

From the plotted graph, find the point that corresponds to 3.5 minutes on the x-axis. Trace vertically until it intersects with the curve. The y-value at this intersection will provide the mass of CO₂ produced in the first 3.5 minutes. Based on the graph, it can be estimated approximately to be around 90 mg.

The rate of the reaction decreases with time. As the reaction proceeds, the concentration of the reactants decreases, resulting in fewer collisions between reactant molecules.

As the eggshell (CaCO₃) is consumed and the concentration of HCl decreases, the rate of the reaction slows down, leading to a decrease in the rate of CO₂ production over time.

A suitable method for crushing broken eggshells would be to use a mortar and pestle for effective grinding.

Reducing the size of the eggshell pieces will likely increase the rate of the reaction. This is because a larger surface area allows for more collisions between reactant molecules, facilitating faster reaction rates. The increased exposure of the solid surface to the acid means more effective contact points for the reaction to occur.

Increasing the temperature by 10 °C will increase the rate of reaction. Typically, higher temperatures result in increased kinetic energy among the reactant molecules, leading to more frequent and energetic collisions, thereby accelerating the reaction rate.