3: Particle Model of Matter

Question 1

What is DENSITY?

Answer 1

Mass per unit volume

Question 2

What does DENSITY depend on?

Answer 2

Spacing of atoms in matter

Question 3

What is the conservation of mass?

Answer 3

Mass is never gained or lost

Question 4

What is always conserved when a substance undergoes a change of state?

Answer 4

Mass

Question 5

Are physical changes reversible?

Answer 5

Yes

Question 6

What is internal energy?

Answer 6

All of the ENERGY(KINETIC + POTENTIAL) of all PARTICLES in a SYSTEM

Question 7

When water boils in an open pan, why does the mass of the pan appear to DECREASE?

Answer 7

• Some water EVAPORATES into VAPOUR
• VAPOUR LEAVES PAN
• Mass DECREASES
• System mass remains CONSTANT

Question 8

Explain what happens when a bathroom mirror mists up

Answer 8

• Hot water EVAPORATES to VAPOUR
• vapour lands on MIRROR
• Vapor CONDENSES and becomes LIQUID on mirror

Question 9

What is Specific Heat Capacity?

Answer 9

Amount of ENERGY required to RAISE the TEMP of 1KG of a substance by 1C

Question 10

what is Specific Latent Heat?

Answer 10

amount of NRG required to CHANGE the TEMP of 1kg of a substance by 1C

Question 11

Explain Pressure in Gases

Answer 11

• Pressure produces NET FORCE at right angles to wall of gas container
• Increasing volume of gas container at CONSTANT TEMP can lead to PRESSURE DECREASE
• because of REDUCED COLLISIONS

Question 12

How to increase pressure of a gas?

Answer 12

Adding more particles:
- More particles in same volume means more likely collissions
- Energy is transferred to particles when more gas is added