P6. Molecules & Matter

Question 1

What are the characteristics of a solid?

Answer 1

Particles are very close together
Particles are arranged in a regular pattern
Particles vibrate but don’t move from place to place

Question 2

What are the characteristics of a liquid?

Answer 2

Particles are close together
Particles are not arranged in a regular patten
Particles can move around each other

Question 3

What are the characteristics of a gas?

Answer 3

Particles are very far apart
Particles are not arranged in any pattern
Particles are moving rapidly

Question 4

What is density?

Answer 4

The density of a material tells us the mass for a given volu e

Question 5

Write down the equation for density.

Answer 5

Density = mass / volume
p = m/v
kg/m^3

Question 6

What is polystyrene in terms of density?

Answer 6

Polysterene is a solid but it has a low density. Polysterene has a very open structure and is full of air spaces. Also it has a small mass for its volume.

Question 7

Required practical: How do you find the density of a regular object?

Answer 7

Use a mass balance and then use a riler to measure the length, width and depth, then times them all together to dind the volume (lxwxd). Then divide the mass by the volume to find the density of the regular object.

Question 8

Required practical: How do you find the density of an irregular object?

Answer 8

1) Find the mass of the object using a balance
2) Fill a Eureka can with water up to the spout making sure it does not overflow
3) Place the irregular object into the Eureka can filled with water - this will cause the water to be displaced and flow out of the eureka can through the spout into the measuring cylinder.
4) The volume of the irregular object = the volume of water displaced divided by the mass (/) mass

Question 9

What is the basic definition of internal energy?

Answer 9

Internal energy is the energy stored in a system by the particles.

Question 10

What does internal energy of a system include?

Answer 10

Internal energy includes the kinetic energy of the particles, due to their movement and the potential energy of the particles due to the forces between the particles and also the bonds between atoms in a molecule.

Question 11

What is specific latent heat?

Answer 11

The specific latent heat of a substance is the AMOUNT OF ENERGY REQUIRED TO CHANGE THE STATE of one kilograms of the substance with no change in temperature.

Question 12

In a heating graph, specific latent heat is shown by the flat lines where the temperature remains constant, why?

Answer 12

In a heating graph specfic latent heat is shown by a flat line where the temperature remains constant because the energy we are putting in is weakeing of breaking the forces of attraction between the particles. (Opposite for cooling graph).

Question 13

What is the specific latent heat of fusion?

Answer 13

The specfic latent heat of fusion is the energy reauired to change 1kg of a substance from a SOLID TO A LIQUID with no change in temperature.

Question 14

What is the specific latent heat of vaporisation?

Answer 14

The specific latent heat of vaporisation is the energy required to change 1kg of a substance from a LIQUID TO A VAPOUR with no change in temperature.

Question 15

Write down the equation for specific latent heat.

Answer 15

energy for a change of state = mass x specific latent heat
E = m x L
J = kg x J/kg

Question 16

Calculate the energy required to convert 0.5kg of ice to liquid water. The specific latent heat of fusion of water is 334000 J/kg. E= m x L CLEAR LAYOUT PLEASE.

Answer 16

0.5 x 334000
= 167000 J

Question 17

What is gas pressure?

Answer 17

Gas pressure is the pressure of a gas due to the particles colliding with the walls of the container that the gas is held in.

Question 18

what happens at high temperature in terms of gas pressure?

Answer 18

At high temperature particles have more kinetic energy. There are more collisions per second. These are higher energy collisions. High pressure.higher

Question 19

what happens at low temperature in terms of gas pressure?

Answer 19

At low tempersture particles have lower kinetic energy. There are fewer collisions per second. These are lower energy collisions. Low pressure