SCI S1 CHAP 7 PARTICULATE NATURE OF MATTER

Question 1

What is Brownian motion?

Answer 1

Brownian motion refers to the random motion of microscopic particles suspended in fluids. This phenomenon provided evidence of the particulate nature of matter.

Question 2

What is the model of particulate nature of matter?

Answer 2

1. All matter is made up of small discrete particles.
2. All particles of one pure substance are identical.
3. Particles of all matter are in continuous and random motion.

Question 3

Describe the movement of particles of a solid.

Answer 3

The particles are held together by very strong forces of attraction and are unable to move about freely. They vibrate about in their fixed positions.

Question 4

Describe the movement of particles of a liquid.

Answer 4

The particles are held together by strong forces of attraction (slightly weaker than those of a solid and are able to slide past one another.

Question 5

Describe the movement of particles of a gas.

Answer 5

The particles are held together by weak forces of attraction and are able to move in random directions at high speeds.

Question 6

Describe the arrangement of particles in a solid.

Answer 6

The particles are packed very closely together and have a fixed, regular pattern.

Question 7

Describe the arrangement of particles in a liquid.

Answer 7

The particles are packed closely together and have no fixed, regular pattern.

Question 8

Describe the arrangement of particles in a gas.

Answer 8

The particles are far apart from one another with no fixed, regular pattern.

Question 9

Describe the physical properties of a solid.

Answer 9

1. Has a definite shape and volume.
2. Has a higher density than liquids and gases.
3. Cannot be compressed.

Question 10

Describe the physical properties of a liquid.

Answer 10

1. Has no definite shape.
2. Has a fixed volume.
3. Has a lower density than solids.
4. Cannot be compressed.

Question 11

Describe the physical properties of a gas.

Answer 11

1. Has no definite shape or volume.
2. Has the lowest density.
3. Can be compressed.

Question 12

In terms of particles, describe what happens as a matter gains heat.

Answer 12

When matter gains heat, it results in expansion. As the matter is heated, the particles gain energy and vibrate more vigorously. The particles move slightly further apart from one another and the distances between them increase. This causes the volume of the substance to increase. This process is known as expansion.

Question 13

In terms of particles, describe what happens when matter loses heat.

Answer 13

When matter loses heat, it results in contraction. When matter is cooled, the particles lose energy and vibrate about their fixed positions less vigorously. The particles move closer to one another and the distances between them decrease. This causes the volume of the matter to decrease. This process is known as contraction.

Question 14

Is mass affected by the expansion and contraction of matter?

Answer 14

During expansion and contraction, the mass does not change. The mass is fixed. The number and size of particles in a substance do not change. Thus, there is a conservation of mass.

Question 15

Identify this diagram and describe what happens during each point/line of the diagram:

https://images.app.goo.gl/fsKz7u2aAgrbMw2N9

Answer 15

Heating curve.

A-B: The substance is completely solid. When the solid is heated, the particles in the solid state gain energy and vibrate more vigorously.

B-C: The substance starts melting at point B, and a mixture of solid and liquid is present. The temperature is constant because thermal energy is taken in to overcome the strong forces of attraction between the particles in the solid state as it melts into the liquid state.

C: The substance has completely melted at point C.

C-D: The substance is completely liquid. When liquid is heated, the particles in the liquid state gain energy and slide past one another faster.

D-E: The particles start to break free from one another and move randomly at point D. The substance starts boiling at point D, and a mixture of liquid and gas is present. The temperature is constant because thermal energy is taken in to overcome the forces of attraction between the particles in the liquid state as it boils into the gaseous state.

E: The substance has completely turned into a gas at point E.

E-F: The substance is in the gaseous state and continues to be heated up.

Question 16

Identify this diagram and describe what happens during each point/line of the diagram:

https://images.app.goo.gl/qJNnFm3ZuBdw2Ltm6

Answer 16

Cooling curve.

A-B: When the gas is cooled, the particles lose energy and move closer to one another and less randomly, the forces of attraction become stronger.

B-C: The substance starts condensation at point B and a mixture of gas and liquid is present. The temperature remains constant as the particles move closer and the forces of attraction between one another become stronger.

C: The substance has completely condensed to liquid at point C.

C-D: When the liquid is cooled, the particles lose energy and move much slower and even closer to one another.

D-E: The substance starts freezing at point D, and a mixture of liquid and solid is present. The temperature remains constant as the particles move closer and the forces of attraction between one another become stronger.

E: The substance has completely turned into a solid at point E.

E-F: The substance is in the solid state and continues to be cooled down.

Question 17

What is diffusion and how does it occur?

Answer 17

Diffusion is the net movement of particles from a region of higher concentration (more particles per unit volume) to a region of lower concentration (less or no particles per unit volume).

Question 18

Why does diffusion occur faster when the temperature rises?

Answer 18

As the temperature rises, the particles slide past one another faster and more vigorously, speeding up the rate of diffusion.

Question 19

What are the keywords/phrases of a model answer for diffusion?

Answer 19

The particles of the (substance) move randomly from a region of higher concentration at (location) to a lower concentration at (location).

Question 20

Name examples of when diffusion occurs.

Answer 20

Tea bag and water

The aroma of cooked food reaching other places or entering our noses.

Question 21

How many particles at min. should be drawn to represent the particles in a solid?

Answer 21

16, draw in 4x4 structure.

Question 22

How many particles at min. should be drawn to represent the particles in a gas?

Answer 22

4-6

Question 23

How many particles at min. should be drawn to represent the particles in a liquid?

Answer 23

10-12, with each particle having at least one point of contact with another particle.

Question 24

Use the particulate nature of matter to describe what happens to the particles as the substance changes from the state of liquid to the state of gas.

Answer 24

The particles start to break free from one another and move randomly freely in all directions. The temperature remains constant because thermal energy is taken to overcome the forces of attraction between the particles in the liquid state as it boils into the gaseous state.