Topic 6 - Molecules and Matter

Question 1

What equation links density, mass and volume?

Answer 1

Density (kg/m3) = mass (kg) / volume (m3) or p = m/v.

Question 2

If a box has a mass of 56kg and a volume of 0.5 m3, what density does it have?

Answer 2

112 kg/m3

Question 3

What is boiling point?

Answer 3

The temperature at which a liquid boils into a gas or condenses back into a liquid.

Question 4

What is a freezing point?

Answer 4

The temperature at which a liquid freezes to become a solid.

Question 5

What is internal energy?

Answer 5

The energy of particles in a substances due to their individual motion and positions.

Question 6

What is latent heat?

Answer 6

The amount of energy need to change the state of 1kg of a substance without change their temperature.

Question 7

What is melting point?

Answer 7

The temperature at which a pure substance melts or solidifies.

Question 8

What is a physical change in a substance?

Answer 8

A change in which no new substances are produced but the appearance of an object may change.

Question 9

What is the pressure of a substance?

Answer 9

The force applied per unit of cross-sectional area, measured in Pa (Pascals).

Question 10

What is the specific latent heat of fusion?

Answer 10

The energy needed to melt 1 kg of a solid with no change in temperature.

Question 11

What is the specific latent heat of vaporisation?

Answer 11

The energy needed to boil away 1 kg of a liquid with no change in temperature.

Question 12

______ can be poured. What state of matter fits the sentence?

Answer 12

Liquids.

Question 13

_____ particles are closely packed together and vibrate about fixed positions. What state of matter fits the sentence?

Answer 13

Solid.

Question 14

_____ particles are very far apart and move around quickly, what state of matter fits best?

Answer 14

Gas.

Question 15

What is the law of conservation of mass in changes of state?

Answer 15

The mass of the products is the same as the mass of the reactants.

Question 16

What is internal energy the sum of?

Answer 16

Internal energy is the sum of all KE and PE (kinetic and potential energy).

Question 17

If particles are further apart they have more?

Answer 17

Potential energy.

Question 18

If particles are faster they have more?

Answer 18

Kinetic energy.

Question 19

What is a plateau?

Answer 19

A flat part of a graph.

Question 20

When heading steric acid from room temperature to above 50 degrees, why does the temperature stop increasing at 32 degrees for a minute and restart increasing again?

Answer 20

The energy is transferred to break the bonds in the steric acid and not to increase its temperature as it has reached its boiling point.

Question 21

What is the equation for specific latent heat?

Answer 21

Energy (J) = mass (kg) x specific latent heat (J/kg) or E = m x lf or lv. Lf is used with specific latent heat of fusion and lv is used in specific latent heat of vaporisation.

Question 22

What is absolute zero?

Answer 22

The coldest possible temperature in the universe.

Question 23

Why is absolute zero the lowest possible temperature in the universe?

Answer 23

It is the point where pressure reaches zero if you continue a graph relating pressure and temperature.

Question 24

What is the Kelvin scale?

Answer 24

The temperature scale that starts at absolute zero, where absolute zero is 0 degrees compared with -273.3 degrees Celsius.

Question 25

How do you convert from kelvin to Celsius?

Answer 25

By adding 273 to your Celsius value.

Question 26

What is Brownian motion?

Answer 26

The idea that particles move randomly, caused by other particles bouncing off of them.

Question 27

What is pascals?

Answer 27

The unit of pressure.

Question 28

What is Boyle’s law?

Answer 28

Pressure (Pa) x Volume (m3) = constant.

Question 29

What is the relationship between pressure and volume?

Answer 29

They are inversely proportional, so as pressure increases, volume decreases.

Question 30

What is the defintion for internal energy?

Answer 30

The sum of kinetic and potential energy of all particles in a system.

Question 31

What is sublimation?

Answer 31

Where a solid can directly turn into a gas.

Question 32

What kind of force is applied by a gas on walls of a container?

Answer 32

A force at right angles, which is called gas pressure.

Question 33

What is the result of carrying out work on a gas?

Answer 33

We transfer energy to gas particles, increasing the internal energy of the gas. This also increases temperature as kinetic energy of particles has increased.