The Particle Modle

Question 1

Limitations of particle model

Answer 1

• does not show true size of particles
• does not show electro static forces between particles
• doesn’t show true distance between particles

Question 2

How are solids arranged

Answer 2

• vibrate around a fixed point
• regular arrangement in a straight line
• very close together

Question 3

How are liquids arranged

Answer 3

• particles close together
• random arrangement but all ways touching
• they are able to move around eachother

Question 4

How are gases arranged

Answer 4

• particles are randomly arranged
• particles are far apart and don’t touch
• the particles move around quickly in all directions

Question 5

What does the particle model show?

Answer 5

• The particle model shows how the particles that make up a substance are arranged, and how they move and interact with each other. The particles are represented as solid spheres, all of the same size

Question 6

How are particles held together

Answer 6

Particles are held together by electrostatic forces

Question 7

How do you calculate the ratio of distance to diameter

Answer 7

Ratio of distance to diameter = distance between atoms / diameter of atoms

Question 8

Why can’t you compress a liquid

Answer 8

You can’t compress a liquid because the particles are all already touching and are close together, but they can still move around each other

Question 9

What does the particle model show

Answer 9

The particle model shows atoms in substances as small spheres, and represents how they are arranged and how they move and interact with each other

Question 10

Describe the change in ARRANGMENT of particles as substances evaporate

Answer 10

Particles are closer together in a liquid and move further apart in a gas

Question 11

Describe the change in the MOVEMENT of particles as substances evaporate.

Answer 11

Particles in a gas move more quickly in all directions than in a liquid

Question 12

When a liquid is heated it will turn into a gas

Use the particle model to explain why this is a physical change

Answer 12

-> the arrangement of the particle changes, but the number and type of particles stays the same
-> the change is reversible
-> no new products are made

Question 13

Rachel tries to react oxygen and nitrogen and increases the temperature

Explain, using the reacting particle model, what happens to the rate of reaction

Answer 13

• the rate of reaction increases
  -particles gain more kinetic energy and move quicker
• more frequent and successful collisions

Question 14

Explain in terms of bind making and breaking why a reaction can be considered endothermic (3 marks)

Answer 14

• breaking bonds is endothermic and making bonds is exothermkc
• more energy is absorbed from the surroundings when making bonds than when bonds are broken