States of matter

Question 1

How are particles in a solid?

Answer 1

Arrangement:

Regular repeating pattern
Close together, touching each other
Movement:

Vibrate about fixed positions but do not move apart
Forces between particles:

Stronger than in a liquid
Shape:

Fixed shape and volume.

Question 2

How are particles in a liquid?

Answer 2

Arrangement:

Irregular
Close together and touching each other
Movement:

Move around and slide past one another
Forces between particles:

Not as strong as solid
Shape:

No fixed shape (takes shape of container) but fixed volume.

Question 3

How are particles in a gas?

Answer 3

Arrangement:

Irregular
Far apart
Movement:

Move freely and collide with each other. Fast, rapid.

Forces between particles:

Non-existent
Shape:

No fixed shape or volume-

Question 4

What is melting?

Answer 4

The process of converting from solid to liquid due to increase in temperature.

Question 5

What is a melting point?

Answer 5

Melting point the temperature at which a solid starts to melt, eg. ice melts at 0 °C.

Question 6

What is boiling?

Answer 6

Boiling the process of converting from liquid to gas due to increase in temperature. Also known as vaporization.

Question 7

What is a boiling point?

Answer 7

Boiling point the temperature at which a liquid starts to boil, eg. water boils at 100 °C.

Question 8

What is condensation?

Answer 8

Condensation the process by which a gas turns to liquid.

Question 9

What is sublimation?

Answer 9

Sublimation the process by which a solid turns directly to gas without melting.

Question 10

What is solidification?

Answer 10

Solidification the process by which a gas turns directly to solid.

Question 11

What is evaporation?

Answer 11

Evaporation the process by which a liquid turns to a gas below its boiling point.

Question 12

What is volatile?

Answer 12

Volatile liquids that evaporate at room temperature.

Question 13

How to get from solid to liquid?

Answer 13

Heat solid until it melts. When a solid is heated the particles gain kinetic energy and start to vibrate faster about their fixed position. When the temperature is high enough, the vibration of particles becomes sufficient to overcome the forces of attraction between them. The particles begin to break away from their regular pattern. They can now slide past each other. The solid becomes a liquid.

Question 14

How to get from liquid to solid?

Answer 14

Cool liquid until it freezes. When a liquid is cooled, the particles lose their kinetic energy. When the temperature is low enough, the particles no longer have the energy to slide over each other. The forces of attraction can hold the particles together in a regular pattern. The substance becomes solid.

Question 15

How to get from liquid to gas?

Answer 15

Heat the liquid until it boils. When a liquid is heated, the particles gain kinetic energy and mover further apart. Eventually, the attractive forces in the liquid are broken. Bubbles of gaseous particles escape from the liquid. The substance becomes gas.

Question 16

How to get from gas to liquid?

Answer 16

Cool the gas until it condenses. When a gas is cooled, the particles lose kinetic energy and the attractive forces become great enough to keep the particles closer together as a liquid.

Question 17

How to get from solid to gas?

Answer 17

Heat the solid until it sublimes. The solid particles gain kinetic energy and vibrate faster. Eventually, the forces of attraction between the particles are completely broken and they escape from the solid as a gas.

Question 18

What experiment is for diffusion and dilution?

Answer 18

Diffusion and dilution experiments support a theory that all matter (solids, liquids and gases) is made up of tiny, moving particles.

Question 19

What was the diffusion experiment with Bromine gas?

Answer 19

Description:

Here, we see the diffusion of bromine gas from one flask to another.
After 5 minutes the bromine gas has diffused from the bottom flask to the top flask.
Explanation:

The air and bromine particles are moving randomly and there are large gaps between particles.
The particles can therefore easily mix together.

Question 20

What is the diffusion experiment with Potassium Manganate solution (VII)?

Answer 20

Description:

When potassium manganate (VII) crystals are dissolved in water, a purple solution is formed.
A small number of crystals produce a highly intense colour.
Explanation:

The water and potassium manganate (VII) particles are moving randomly and the particles can slide over each other.
The particles can therefore easily mix together.
Diffusion in liquids is slower than in gases because the particles in a liquid are closely packed together and move more slowly.

Question 21

What is the experiment with potassium manganate and dilution?

Answer 21

When potassium magnate (VII) crystals are dissolved in water, the solution can be diluted several times.
The colour fades but does not disappear until a lot of dilutions have been done.
Explanation:

This indicates that there are a lot of particles in a small amount of potassium magnate (VII) and therefore the particles must be very small.

Question 22

What is a solvent?

Answer 22

The liquid in which a solute dissolves

Question 23

What is a solute?

Answer 23

The substance which dissolves in a liquid to form a solution.

Question 24

What is a solution?

Answer 24

The mixture formed when a solute is dissolved in a solvent

Question 25

What is a saturated solution?

Answer 25

A solution with the maximum concentration of solute dissolved in the solvent.

Question 26

What is soluble?

Answer 26

Describes a substance that will dissolve.

Question 27

What is in insoluble?

Answer 27

Describes a substance that won’t dissolve.

Question 28

How do you express solubility?

Answer 28

Different substances have different solubilities.
Solubility can be expressed in g per 100 g of solvent.
Solubility of solids is affected by temperature. As temperature increases, solids become more soluble.
Solubility of gases is affected by temperature and pressure. As pressure increases, gases become more soluble. As temperature increases, gases become less soluble, in general.

Question 29

What are solubility curves?

Answer 29

Solubility graphs represent solubility in g per 100 g of water plotted against temperature.
To plot a solubility curve, the maximum mass of solvent that can be dissolved in 100 g of water before a saturated solution is formed, is determined at a series of different temperatures.

Question 30

How much potassium nitrate will dissolve in 20g of water at 34 °C?

Answer 30

At 34 °C the solubility is 49g per 100g of water

So scaling, 49 x 20 / 100 = 9.8 g of potassium nitrate will dissolve in 20 g of water.

Question 31

200 cm3 of saturated copper solution was prepared at a temperature of 90 °C. What mass of copper sulphate crystals form if the solution was cooled to 20 °C?

Answer 31

Solubility of copper sulphate at 90 oC is 67g/100g water, and 19g/100g water at 20 °C.

Therefore for mass of crystals formed = 67 – 19 = 48g (for 100 cm3 of solution).

However, 200 cm3 of solution was prepared,

So total mass of copper sulphate crystallised = 2 x 48 = 96g

Question 32

What is the effect of solubility on gas in warmer temperatures?

Answer 32

Unlike salts, shown in the previous graph, gases become less soluble as temperature increases. E.g. fizzy drinks become flat more quickly when left at a warmer temperature.

Question 33

How to conduct a solubility experiment?

Answer 33

Take down volume of water and heat to specific temperature, e.g. in a water bath set to desired temperature. Keep thermometer in water to make sure temperature is maintained throughout.
Add known masses of solvent bit by bit, until saturated solution formed – when solid stops dissolving and remains as solid in solution.
Record mass of solid that was soluble.
Repeat with different temperature.
Can plot solubility curve as seen above.