Define melting point .

The melting point is the specific temperature at which a solid changes into a liquid (and a liquid into a solid).

How does particle arrangement differ between solids , liquids and gases ?

Particle arrangement differs across the three states. In a solid , particles are in a regular arrangement. In a liquid and a gas , particles are randomly arranged, but in a liquid they are close together and in a gas they are far apart.

True or False? Freezing occurs at a different temperature from melting for a pure substance.

False. For a pure substance, freezing and melting occur at the same temperature , known as the melting point. For example, water melts and freezes at 0 °C.

Melting is a .......... change. The .......... themselves remain the same, and only the forces between them change.

Melting is a physical change. The particles themselves remain the same, and only the forces between them change.

Sublimation is when a solid changes directly into a gas, without passing through the liquid state. Only a few substances undergo sublimation, such as iodine and solid carbon dioxide.

Why do substances with stronger forces between particles have higher melting points and boiling points ?

Stronger forces between particles require more energy to overcome. This means a higher temperature is needed to change state, so the melting point and boiling point of the substance are higher.

True or False? Evaporation only occurs at the boiling point of a liquid.

False. Evaporation occurs over a range of temperatures and can happen below the boiling point . It takes place only at the surface of a liquid, where high-energy particles can escape.

Properties of the three states of matter — complete the table. Solid Liquid Gas Arrangement of particles Randomly arranged Movement of particles Vibrate about a fixed position Move quickly in all directions Closeness of particles Very close Far apart

Solid Liquid Gas Arrangement of particles Regular arrangement Randomly arranged Randomly arranged Movement of particles Vibrate about a fixed position Move around each other Move quickly in all directions Closeness of particles Very close Close Far apart

How does boiling differ from evaporation ?

Boiling occurs at a specific temperature (the boiling point) and produces bubbles of gas inside the liquid. Evaporation occurs over a range of temperatures and happens only at the surface of the liquid, where high-energy particles escape.

Define condensation .

Condensation is when a gas changes into a liquid on cooling. The gas particles lose energy and group together to form a liquid.

Diffusion is the spreading of particles through a substance due to their random movement . Diffusion results in particles mixing together evenly over time.

Why does diffusion occur more slowly in liquids than in gases ?

Diffusion is slower in liquids because the particles are more closely packed together and move more slowly than in gases. In gases , particles have large gaps between them and move freely, allowing faster mixing.

True or False? Diffusion in gases is slower than diffusion in liquids.

False. Diffusion in gases is faster than in liquids. In gases, particles are more spread out and move more quickly, so they mix together more rapidly.

Diffusion and dilution experiments provide evidence that all matter is made up of tiny, .......... particles.

Diffusion and dilution experiments provide evidence that all matter is made up of tiny, moving particles.

What does the dilution experiment with potassium manganate(VII) suggest about the size of particles?

The colour of potassium manganate(VII) solution only disappears after many dilutions, showing that there are a very large number of particles in a small amount of the substance. This means the particles must be very small .

True or False? Diffusion in gases occurs because particles move randomly and there are large gaps between them.

True. Gas particles move randomly and have large gaps between them, allowing them to spread out and mix together easily. This random movement is what drives diffusion .

Dilution is the process of adding more solvent to a solution, which reduces the intensity of its properties, such as colour. Even after many dilutions, particles are still present, showing how many tiny particles exist in a small sample.

In the bromine diffusion experiment, .......... gas spreads from one gas jar to another because particles move .......... and there are large .......... between them.

In the bromine diffusion experiment, red-brown gas spreads from one gas jar to another because particles move randomly and there are large gaps between them.

A solute is the substance that dissolves in a liquid to form a solution. For example, salt is the solute in sea water.

How does a solution form?

A solution forms when a solute dissolves in a solvent . The solute particles spread throughout the solvent to create a uniform mixture.

Define saturated solution .

A saturated solution is a solution that contains the maximum amount of solute that can dissolve in the solvent at a given temperature. Adding more solute will not cause it to dissolve.

True or False? A saturated solution can dissolve more solute if it is stirred vigorously.

False. A saturated solution already contains the maximum amount of solute that can dissolve at that temperature. Stirring does not allow more solute to dissolve.

Complete the table of solutions terminology. Term Meaning Solvent Solute Solution Saturated solution Soluble Insoluble

Term Meaning Solvent The liquid in which a solute dissolves Solute The substance which dissolves in a liquid to form a solution Solution The mixture formed when a solute is dissolved in a solvent Saturated solution A solution with the maximum concentration of solute dissolved in the solvent Soluble Describes a substance that will dissolve Insoluble Describes a substance that will not dissolve

What does insoluble mean?

Insoluble describes a substance that will not dissolve in a given solvent. For example, sand is insoluble in water.

A solution is the mixture formed when a solute dissolves in a solvent . Sea water is an example, where salt is the solute and water is the solvent.

True or False? Sand is an example of a substance that is soluble in water.

False. Sand is insoluble in water and does not dissolve.

Solubility is a measure of how much of a substance will dissolve in a given volume of a liquid. It is expressed in g per 100 g of solvent .

How does increasing temperature affect the solubility of solids and gases differently?

For most solids , solubility increases as temperature rises. For gases , solubility decreases as temperature increases, so gases become less soluble when heated.

True or False? As temperature increases, gases become more soluble in water.

False. As temperature increases, gases become less soluble in water. It is solids that usually become more soluble as temperature rises.

Solubility is expressed in units of .......... per .......... of solvent.

Solubility is expressed in units of g per 100 g of solvent.

What is a solubility curve ?

A solubility curve is a graph showing how the solubility of a substance changes with temperature. Solubility (in g per 100 g of water) is on the y -axis and temperature is on the x -axis.

How does increasing pressure affect the solubility of a gas ?

Increasing pressure causes gases to become more soluble in a liquid. This is because higher pressure forces more gas particles into the liquid.

True or False? Most solids become more soluble as temperature increases.

True. As temperature increases, the solubility of most solids increases. This is the opposite of gases, which become less soluble when heated.

As temperature increases, the solubility of most solids .......... , but the solubility of gases .......... .

As temperature increases, the solubility of most solids increases , but the solubility of gases decreases .

What does a solubility curve show?

A solubility curve shows how the solubility of a substance changes with temperature. It can be used to find the solubility at any temperature, or to determine how much solute crystallises when a solution is cooled.

What is the aim of the solubility practical?

The aim of the solubility practical is to measure the solubility of a solid (such as ammonium chloride) in water at different temperatures. This allows a solubility curve to be plotted.

What does solubility in g per 100 g mean?

Solubility in g per 100 g means the mass of solute (in grams) that dissolves in 100 g of solvent. It is calculated by dividing the mass of solute by the volume of water and multiplying by 100.

True or False? In the solubility practical, crystals first appear when the solution becomes saturated on cooling.

True. When the solution is cooled, it reaches the point at which no more solute can remain dissolved, so crystals of the solid begin to form. The temperature at which this happens is recorded.

How is solubility in g per 100 g calculated from the practical results?

Solubility in g per 100 g is calculated by dividing the mass of solute by the volume of water used, then multiplying by 100. For example, 2.6 g of solute in 4 cm 3 of water gives a solubility of 65 g per 100 g.

In the solubility practical, the temperature at which crystals first appear is the temperature at which the solution becomes .......... .

In the solubility practical, the temperature at which crystals first appear is the temperature at which the solution becomes saturated .

What is plotted on the axes of a solubility curve graph?

Solubility (in g per 100 g of water) is plotted on the y -axis and temperature is plotted on the x -axis. The resulting curve shows how solubility changes with temperature.

IGCSEChemistryEdexcelChemistry (Modular)Unit 1Flashcards1. Principles of Chemistry: Part 1States of matter

States of matter (Edexcel IGCSE Chemistry (Modular): Unit 1): Flashcards

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FrontThe Three States of Matter
Define melting point.

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Cards in this collection (41)

Define melting point.
The melting point is the specific temperature at which a solid changes into a liquid (and a liquid into a solid).
How does particle arrangement differ between solids, liquids and gases?
Particle arrangement differs across the three states. In a solid, particles are in a regular arrangement. In a liquid and a gas, particles are randomly arranged, but in a liquid they are close together and in a gas they are far apart.
True or False?
Freezing occurs at a different temperature from melting for a pure substance.
False.
For a pure substance, freezing and melting occur at the same temperature, known as the melting point. For example, water melts and freezes at 0 °C.
Melting is a .......... change. The .......... themselves remain the same, and only the forces between them change.
Melting is a physical change. The particles themselves remain the same, and only the forces between them change.
Define sublimation.
Sublimation is when a solid changes directly into a gas, without passing through the liquid state. Only a few substances undergo sublimation, such as iodine and solid carbon dioxide.
Why do substances with stronger forces between particles have higher melting points and boiling points?
Stronger forces between particles require more energy to overcome. This means a higher temperature is needed to change state, so the melting point and boiling point of the substance are higher.
True or False?
Evaporation only occurs at the boiling point of a liquid.
False.
Evaporation occurs over a range of temperatures and can happen below the boiling point. It takes place only at the surface of a liquid, where high-energy particles can escape.

Properties of the three states of matter — complete the table.

	Solid	Liquid	Gas
Arrangement of particles		Randomly arranged
Movement of particles	Vibrate about a fixed position		Move quickly in all directions
Closeness of particles	Very close		Far apart

	Solid	Liquid	Gas
Arrangement of particles	Regular arrangement	Randomly arranged	Randomly arranged
Movement of particles	Vibrate about a fixed position	Move around each other	Move quickly in all directions
Closeness of particles	Very close	Close	Far apart

How does boiling differ from evaporation?
Boiling occurs at a specific temperature (the boiling point) and produces bubbles of gas inside the liquid. Evaporation occurs over a range of temperatures and happens only at the surface of the liquid, where high-energy particles escape.
Define condensation.
Condensation is when a gas changes into a liquid on cooling. The gas particles lose energy and group together to form a liquid.
Define diffusion.
Diffusion is the spreading of particles through a substance due to their random movement. Diffusion results in particles mixing together evenly over time.
Why does diffusion occur more slowly in liquids than in gases?
Diffusion is slower in liquids because the particles are more closely packed together and move more slowly than in gases. In gases, particles have large gaps between them and move freely, allowing faster mixing.
True or False?
Diffusion in gases is slower than diffusion in liquids.
False.
Diffusion in gases is faster than in liquids. In gases, particles are more spread out and move more quickly, so they mix together more rapidly.
Diffusion and dilution experiments provide evidence that all matter is made up of tiny, .......... particles.
Diffusion and dilution experiments provide evidence that all matter is made up of tiny, moving particles.
What does the dilution experiment with potassium manganate(VII) suggest about the size of particles?
The colour of potassium manganate(VII) solution only disappears after many dilutions, showing that there are a very large number of particles in a small amount of the substance. This means the particles must be very small.
True or False?
Diffusion in gases occurs because particles move randomly and there are large gaps between them.
True.
Gas particles move randomly and have large gaps between them, allowing them to spread out and mix together easily. This random movement is what drives diffusion.
Define dilution.
Dilution is the process of adding more solvent to a solution, which reduces the intensity of its properties, such as colour. Even after many dilutions, particles are still present, showing how many tiny particles exist in a small sample.
In the bromine diffusion experiment, .......... gas spreads from one gas jar to another because particles move .......... and there are large .......... between them.
In the bromine diffusion experiment, red-brown gas spreads from one gas jar to another because particles move randomly and there are large gaps between them.
Define solute.
A solute is the substance that dissolves in a liquid to form a solution. For example, salt is the solute in sea water.
How does a solution form?
A solution forms when a solute dissolves in a solvent. The solute particles spread throughout the solvent to create a uniform mixture.
Define saturated solution.
A saturated solution is a solution that contains the maximum amount of solute that can dissolve in the solvent at a given temperature. Adding more solute will not cause it to dissolve.
True or False?
A saturated solution can dissolve more solute if it is stirred vigorously.
False.
A saturated solution already contains the maximum amount of solute that can dissolve at that temperature. Stirring does not allow more solute to dissolve.

Complete the table of solutions terminology.

Term	Meaning
Solvent
Solute
Solution
Saturated solution
Soluble
Insoluble

Term	Meaning
Solvent	The liquid in which a solute dissolves
Solute	The substance which dissolves in a liquid to form a solution
Solution	The mixture formed when a solute is dissolved in a solvent
Saturated solution	A solution with the maximum concentration of solute dissolved in the solvent
Soluble	Describes a substance that will dissolve
Insoluble	Describes a substance that will not dissolve

What does insoluble mean?
Insoluble describes a substance that will not dissolve in a given solvent. For example, sand is insoluble in water.
What is a solution?
A solution is the mixture formed when a solute dissolves in a solvent. Sea water is an example, where salt is the solute and water is the solvent.
True or False?
Sand is an example of a substance that is soluble in water.
False.
Sand is insoluble in water and does not dissolve.
Define solubility.
Solubility is a measure of how much of a substance will dissolve in a given volume of a liquid. It is expressed in g per 100 g of solvent.
How does increasing temperature affect the solubility of solids and gases differently?
For most solids, solubility increases as temperature rises. For gases, solubility decreases as temperature increases, so gases become less soluble when heated.
True or False?
As temperature increases, gases become more soluble in water.
False.
As temperature increases, gases become less soluble in water. It is solids that usually become more soluble as temperature rises.
Solubility is expressed in units of .......... per .......... of solvent.
Solubility is expressed in units of g per 100 g of solvent.
What is a solubility curve?
A solubility curve is a graph showing how the solubility of a substance changes with temperature. Solubility (in g per 100 g of water) is on the y-axis and temperature is on the x-axis.
How does increasing pressure affect the solubility of a gas?
Increasing pressure causes gases to become more soluble in a liquid. This is because higher pressure forces more gas particles into the liquid.
True or False?
Most solids become more soluble as temperature increases.
True.
As temperature increases, the solubility of most solids increases. This is the opposite of gases, which become less soluble when heated.
As temperature increases, the solubility of most solids .........., but the solubility of gases ...........
As temperature increases, the solubility of most solids increases, but the solubility of gases decreases.
What does a solubility curve show?
A solubility curve shows how the solubility of a substance changes with temperature. It can be used to find the solubility at any temperature, or to determine how much solute crystallises when a solution is cooled.
What is the aim of the solubility practical?
The aim of the solubility practical is to measure the solubility of a solid (such as ammonium chloride) in water at different temperatures. This allows a solubility curve to be plotted.
What does solubility in g per 100 g mean?
Solubility in g per 100 g means the mass of solute (in grams) that dissolves in 100 g of solvent. It is calculated by dividing the mass of solute by the volume of water and multiplying by 100.
True or False?
In the solubility practical, crystals first appear when the solution becomes saturated on cooling.
True.
When the solution is cooled, it reaches the point at which no more solute can remain dissolved, so crystals of the solid begin to form. The temperature at which this happens is recorded.
How is solubility in g per 100 g calculated from the practical results?
Solubility in g per 100 g is calculated by dividing the mass of solute by the volume of water used, then multiplying by 100. For example, 2.6 g of solute in 4 cm³ of water gives a solubility of 65 g per 100 g.
In the solubility practical, the temperature at which crystals first appear is the temperature at which the solution becomes ...........
In the solubility practical, the temperature at which crystals first appear is the temperature at which the solution becomes saturated.
What is plotted on the axes of a solubility curve graph?
Solubility (in g per 100 g of water) is plotted on the y-axis and temperature is plotted on the x-axis. The resulting curve shows how solubility changes with temperature.

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