P6- Molecules and matter

Question 1

What is density

Answer 1

The mass per volume of a substance

Question 2

What is needed to measure the density of an object or liquid?

Answer 2

The mass and volume then use the equation

Question 3

3 ways to find the volume of an object

Answer 3

Regular object- Use measurements to calculate volume
Irregular object- Tie string to it, place in half full measuring cylinder, calculate water level rise
Irregular object- Fill eureka can w water up to spout, place object in, collect water from spout in beaker. Measure displaced water with measuring cylinder

Question 4

When do objects float on water?

Answer 4

If they have a lower density than water

Question 5

Conservation of mass meaning

Answer 5

When a substance changes state the mass stays the same

Question 6

Particles in solid
Arrangement?
Energy?

Answer 6

Next to each other in fixed positions
Least energetic

Question 7

Particles in liquid
Arrangement?
Energy?

Answer 7

Move around at random, touch each other
More energetic

Question 8

Particles in gas
Arrangement?
Energy?
Density?

Answer 8

Move randomly and far apart
Most energetic
Much less dense than solids and liquids

Question 9

The temperature of water when heated over time

Answer 9

-Increases until 0°, ice starts to melt
-Stays at 0° until all ice has melted
-Increases from 0° to 100°, water starts to boil
-Stays at 100° until all water turns to steam

Question 10

Specific latent heat

Answer 10

The energy transferred to a substance when it changes state

Question 11

Where does boiling and evaporation occur in a liquid and when?

Answer 11

Boiling- throughout a liquid at its boiling point
Evaporation- surface of liquid when below boiling point

Question 12

How to tell the melting and boiling point of a substance from a temp-time graph?

Answer 12

The flat section

Question 13

Internal energy definition and sum

Answer 13

Kinetic energy + potential energy
The energy of particles caused by their motion and position

Question 14

Kinetic energy increases by…
Potential energy increases by…

Answer 14

Rise in temperature

Change of state

Question 15

Pressure

Answer 15

The force of the particles colliding with the sides of a container

Question 16

What happens to gas pressure if temp increases?

Answer 16

-Gas particles move quickly in random directions
-Pressure is collision of particles with sides of container
-Particles gain KE, move quicker, collide w sides of container more frequently w more force
-Pressure increases

Question 17

Latent heat of fusion

Answer 17

The energy needed to change the 1kg of a substance from solid to liquid (melting)

Question 18

Latent heat of vaporisation

Answer 18

The energy need to change 1kg of a substance from liquid to gas (vaporisation)

Question 19

Boyle’s law

Answer 19

At a constant temp:
-if volume doubles, pressure halves
-if volume halves, pressure doubles

Question 20

What happens to gas pressure if volume decreases?

Answer 20

-Particles forced closer together
-More collisions with sides of container
-Increases pressure

Question 21

What happens to gas if it is compressed rapidly and why?

Answer 21

Temp of gas can increase, work is done, energy not transferred to surroundings quick enough