Define rate of a chemical reaction - Leaving Cert Chemistry - Question 7 - 2003

To demonstrate the effect of particle size on the rate of reaction, one can use marble chips of different sizes. The experiment involves:

1. Preparation: Measure equal masses of marble chips of varying sizes (large, medium, small).
2. Reactants: Use equal concentrations of hydrochloric acid (HCl) and add to each set of marble chips in separate beakers.
3. Observation: Monitor the time taken for gas bubbles (CO₂) to evolve.
4. Conclusion: Smaller particles will produce gas more quickly due to a larger surface area, thus increasing the rate of reaction.

To demonstrate the effect of concentration on the rate of reaction, follow these steps:

1. Experimental Setup: Use equal volumes of HCl at different concentrations (e.g., dilute and concentrated).
2. Procedure: Add equal amounts of marble chips to each beaker containing HCl.
3. Data Collection: Measure the time taken for the reaction to complete in each setup by observing the volume of gas produced.
4. Analysis: A higher concentration of acid will result in a faster rate of reaction due to more frequent collisions between reactant particles.

A catalyst is a substance that alters (speeds up) the rate of a chemical reaction without being consumed in the process. It remains chemically unchanged at the end of the reaction.

One reaction catalyzed in the catalytic converter is the conversion of carbon monoxide (CO) to carbon dioxide (CO₂). This is generally facilitated by a platinum catalyst.

One environmental benefit of this process is the reduction of toxic emissions, such as carbon monoxide, thus helping to mitigate air pollution and improve air quality.

One element commonly used as a catalyst in catalytic converters is platinum.

The type of catalysis involved in a catalytic converter is heterogeneous catalysis, where the catalyst is in a different phase (solid) than the reactants (gases).