3. Physical Chemistry - Chemistry

How do you investigate the effect of surface area on rate?

Use marble chips of different sizes reacting with HCl and measure CO₂ volume over time.

How do you investigate the effect of concentration on rate?

React marble chips with different concentrations of HCl and measure gas produced.

How do you investigate the effect of temperature on rate?

Heat/cool a reactant solution and measure time for visible change (e.g., disappearing cross).

How do you investigate the effect of a catalyst on rate?

Decompose H₂O₂ with and without catalyst (e.g., MnO₂) and compare oxygen production.

What is the effect of increased surface area on rate?

Increases rate.

What is the effect of increased concentration on rate?

Increases rate.

What is the effect of increased pressure (gases) on rate?

Increases rate.

What is the effect of increased temperature on rate?

Increases rate.

What is the effect of a catalyst on rate?

Increases rate.

Why does increasing surface area increase rate?

More particles exposed → more frequent collisions.

Why does concentration increase rate?

More particles per volume → more collisions.

Why does pressure increase rate?

Gas particles are closer → more collisions.

Why does temperature increase rate?

Particles have more energy → more frequent + energetic collisions.

What is a catalyst?

A substance that speeds up a reaction but is unchanged at the end.

How do catalysts work?

Provide an alternative pathway with lower activation energy.

How to investigate effect of surface area using marble chips?

React small vs large chips with HCl; measure CO₂ volume/time.

How to investigate concentration using marble chips?

Use different HCl concentrations and measure rate of gas production.

How to investigate catalysts using hydrogen peroxide?

Add different solids (e.g., MnO₂) and measure rate of oxygen release.