Particles and Rate of Reaction (TOPIC 13)

Question 1

What are the characteristics of a solid?

Answer 1

Strong forces of attraction between particles hold them close together in fixed positions where they vibrate around a fixed point.

Question 2

What are the characteristics of a liquid?

Answer 2

Weak force of attraction between particles.

Random arrangement flow around and over each other.

Definite volume not shape

Expand slightly when heated

Question 3

What are the characteristics of gases?

Answer 3

Very weak forces of attraction free to move far apart

Constantly move in random directions in straight lines

No definite shape or volume

When heated they expand or pressure increases

Question 4

Solid to liquid?

Answer 4

Melting

Question 5

Solid to gas?

Answer 5

Sublimation

Question 6

Gas to liquid?

Answer 6

Condensing

Question 7

Liquid to solid?

Answer 7

Freezing

Question 8

Liquid to gas?

Answer 8

Evaporation

Question 9

Describe what happens to the particles in the solid when they get heated.

Answer 9

Gain energy, heat to kinetic
Vibrate quicker
This weakens the forces that hold them together
Then at a certain temp called melting point the particles have enough energy to break free from their positions

Question 10

What is diffusion?

Answer 10

Movement of particles from an area of high concentration to low concentration.

Question 11

How do reactions happen?

Answer 11

When particles collide with enough energy they react. When particles collide with greater to or equal to the activation energy it is a successful collision

Question 12

What factors affect rate of reaction?

Answer 12

Concentration
Catalyst
Temperature
Surface area/particle size

Question 12

How does the concentration affect rate of reaction?

Answer 12

More particles in a fixed volume means more frequent collision so there will be more chance of successful collisions

Question 13

How does the temperature affect rate of reaction?

Answer 13

Higher temperature means more kinetic energy in the particles so there is more frequent collisions with higher energy. More successful collisions.

Question 14

How does the Surface Area affect rate of reaction?

Answer 14

Increase in surface area means a larger SA to Volume ration allows more collisions at the surface.

Question 15

How does a catalyst affect the rate of reactions?

Answer 15

Increases the rate of reaction by offering an alternative energy pathway with a lower activation energy.

Therefore more particles have the energy required for a successful collision.

Question 16

What is catalyst?

Answer 16

A substance that increases the rate of reaction by offering an alternative pathway with lower activation energy.

Is not used up at the end of the reaction.

Question 17

Investigate the effect of changing the surface area of calcium carbonate chips on the rate of reaction.

Answer 17

Using an air tight concical flask with a bung on top attached to a gas syringe.

Add 20cm3 of dilute HCl to the conical flask. Weigh out 2g of CaCO3 add to the conical flask. Measure the volume of CO2 gas produced from the reaction in the gas syringe.

Repeat using the same mass of Chips and volume and concentration of acid but different size of chip.

Question 18

Investigate the effect on the catalytic decomposition of hydrogen peroxide solution

Answer 18

Add hydrogen peroxide into a conical flask

Use a delivery tube to connect this flask to a measuring cylinder upside down in water trough

Add the chosen catalyst into the conical flask and close the bung

Measure the volume of gas produced in a fixed time using the measuring cylinder - the volume of water displaced

Repeat experiment with different solids and compare results