5.2- 5.2.5 - Changes of state

Question 1

What are the 3 states of matter?

Answer 1

Solid liquid and gas

Question 2

How are particles arranged in a solid?

Answer 2

Particles are closely packed, the particles vibrate about a fixed position.
Solids have a defined shape and a defined volume.

Question 3

How are particles arranged in a liquid?

Answer 3

In a liquid the particles are closely packed together and they can flow over one another.
They have no defined shape but are able to flow and take the shape of the container
They have a defined volume.

Question 4

How are particles arranged in a gas?

Answer 4

In a gas the particles are far apart they have random movement
they have no fixed volume- if placed in a evacuated container they will expand to fill the container
they have no defined shape- will take the shape of their container

Gases are highly compressible because there are large gaps between the particles and it is easier to push the particles closer together than in solids or liquids.

Question 5

What causes a substance to change state?

Answer 5

The number of molecule in that substance doesn’t change neither does its mass only thing that changes is its energy
Changes of states are reversable

Question 6

What are the 6 changes of state that occour between matter?

Answer 6

Melting- When a solid turns into a liquid
Boiling- When a liquid turns into a gas
Condensing- When a gas turns into a liquid
Freezing-When a liquid turns into a solid
Subliming- When a solid turns into a gas

Question 7

What effect does Heat and tempreture have on change of states?

Answer 7

Heating a system will change the energy store by increasing the Kinetic energy of its particles
The tempreture of the materials is related to the average K.N of the molecules
An increase in K.N can cause the tempreture of the system to increase or produce change of states
the higher the temp the high the average K.N of the molecules so they move quicker

Question 8

Explain the core practical about investigating change of states?

Answer 8

The aim of this experiment is to investigate how the temperature of ice varies when it changes state from a solid to a liquid
Place the ice cubes in the beaker (it should be about half full)
Place the thermometer in the beaker
Place the beaker on the tripod and gauze and slowly start to heat it using the bunsen burner
As the beaker is heated, take regular temperature measurements (e.g. at one minute intervals)
Continue this whilst the substance changes state (from solid to liquid)

Question 9

Explain the analysis of the results for core practical 10?

Answer 9

Plot a graph of the temperature (y-axis) against time (x-axis)
The graph will show regions where:
The temperature of the ice cubes increases
There is no temperature change (even though the ice cubes continue to be heated)
This should occur at 0 °C, where the ice is melting from solid to liquid

Question 10

Explain which errors can occour in core practical 10?

Answer 10

Systematic Errors:

Measurements of temperature from the thermometer keeping it at eye level, to avoid parallax errors
Ensure the thermometer is held vertically in the beaker
Random Errors:

Ensure there are enough ice cubes to surround the thermometer in the beaker, and only begin the experiment when the temperature is below 0 °C
This is to ensure readings of temperature are as accurate as possible

Question 11

What does the tempreture of a system increasing depend on?

Answer 11

The mass of the substance heated
The type of material
The amount of energy put in to the system
The energy put in is in the form of thermal energy

Question 12

What is specific heat capacity defined as?

Answer 12

The amount of energy required to raise the temperature of 1 kg of the substance by 1 °C

Question 13

Whats the difference between low specific heat capacity substances and high substances?

Answer 13

If a substance has a low specific heat capacity, it heats up and cools down quickly (ie. it takes less energy to change its temperature)
If a substance has a high specific heat capacity, it heats up and cools down slowly (ie. it takes more energy to change its temperature)

Question 14

What is the calculation for Specific Heat Capacity?

Answer 14

Change in thermal energy = Mass x specific heat capacity x change in tempreture

Question 15

what are the aims of core practical 11 investigating Heat Capacity?

Answer 15

Aim of this experiment is to determine the specific heat capacity of a solid and of water by measuring the energy required to increase the tempreture of a known mount by one degree.

Question 16

Explain the experiment: Finding the Specific Heat Capacity of a metal

Answer 16

1) Find he mass of the metal cylinder and record it in the table

2) Place the thermometer in the block and measure the initial tempreture of the block and record it

3) Place the heater in the block and connect it to a circut

4) Set up the power supply to around 10V and switch on the heater, starting the stop clock at the same time

5) Record the voltage and current in a table

6) After 5 minutes switch the heater off the tempreture will continue to rise record the highest tempreture the block reaches in the table