Explain why the balloon inflates (3 marks) and why powdered CaCO3 makes it inflate faster (3 marks).

The reaction between calcium carbonate ($\text{CaCO}_3$) and hydrochloric acid ($\text{HCl}$) produces carbon dioxide gas ($\text{CO}_2$).

The carbon dioxide gas produced increases the amount of gas inside the flask. This increase in gas volume or pressure pushes against the walls of the balloon.

The outward pressure exerted by the newly formed $\text{CO}_2$ gas causes the balloon to expand and inflate.

xx) If the same mass of $\text{CaCO}_3$ in a powdered form is used, the balloon inflates faster. Explain why using collision theory (3 marks).

Using $\text{CaCO}_3$ in powdered form significantly increases its surface area compared to pieces.

According to collision theory, a larger surface area means more $\text{CaCO}_3$ particles are exposed and available to collide with $\text{HCl}$ particles at any given time.

This leads to a higher frequency of effective collisions between the reactant particles. A greater number of effective collisions per unit time results in a faster rate of reaction, thus producing $\text{CO}_2$ gas more quickly and inflating the balloon faster.

xxi) Using the same chemical substances and collision theory, discuss two other ways to make the balloon inflate faster (4 marks).

1. Increase the concentration of $\text{HCl}$: According to collision theory, increasing the concentration of $\text{HCl}$ means there are more $\text{HCl}$ particles per unit volume. This increases the frequency of collisions between $\text{HCl}$ and $\text{CaCO}_3$ particles. A higher frequency of collisions leads to a greater number of effective collisions, thus speeding up the production of $\text{CO}_2$ gas and inflating the balloon faster.

2. Increase the temperature of the reaction: According to collision theory, increasing the temperature increases the kinetic energy of the reactant particles. This has two effects:

   • The particles move faster, leading to a higher frequency of collisions.
   • A larger proportion of collisions will have energy equal to or greater than the activation energy, resulting in more effective collisions. Both factors contribute to a faster reaction rate, leading to quicker $\text{CO}_2$ production and faster balloon inflation.