Define solid (as a state of matter).

In a solid , particles are closely packed and vibrate about fixed positions. Solids have a definite shape and a definite volume .

Define liquid (as a state of matter).

In a liquid , particles are closely packed but can flow over one another. Liquids have no definite shape, but do have a definite volume .

Define gas (as a state of matter).

In a gas , particles are far apart and move randomly . Gases have no definite shape and no fixed volume .

Why are gases highly compressible , unlike solids and liquids?

There are large gaps between gas particles, so it is much easier to push the particles closer together than in a solid or liquid.

How does the energy of particles compare across the three states of matter?

Particles in a solid have the lowest energy, particles in a liquid have greater energy, and particles in a gas have the highest energy.

Particles in a solid vibrate about ______ positions, while particles in a liquid can ______ over one another.

Particles in a solid vibrate about fixed positions, while particles in a liquid can flow over one another.

True or False? A liquid has a definite shape.

False. A liquid has no definite shape — it flows and takes the shape of its container — but it does have a definite volume .

Melting is the change of state from a solid to a liquid. At the melting point, energy supplied is transferred to the particles' potential store , breaking the rigid bonds so they can flow over each other.

Evaporation is the change of state from a liquid to a gas that can happen at any temperature, not just the boiling point. Only the most energetic particles at the surface of the liquid have enough energy to escape the intermolecular bonds.

What are two differences between evaporation and boiling ?

Evaporation can occur at any temperature, whereas boiling only occurs at the boiling point. Bubbles of gas form within the liquid during boiling, but not during evaporation.

Define internal energy .

The internal energy of a system is the sum of the kinetic energy of its particles (due to their motion) and the potential energy of its particles (due to their position relative to each other).

Why does the temperature of a substance stay constant while it is changing state, even though it is still being heated?

The energy supplied goes into the potential store of the particles, breaking the intermolecular bonds, while the kinetic energy of the particles — and therefore the temperature — stays constant.

The ______ of a substance is related to the average ______ of its molecules.

The temperature of a substance is related to the average kinetic energy of its molecules.

True or False? During evaporation, bubbles of gas form throughout the liquid.

False. Bubbles of gas form throughout the liquid during boiling . During evaporation, only particles at the surface escape — no bubbles form.

What is the aim of the core practical investigating changes of state?

To investigate how the temperature of ice varies as it changes state from a solid to a liquid, by heating it and recording the temperature at regular time intervals.

What equipment is used to heat and support the beaker of ice in this experiment?

A Bunsen burner heats the beaker, which is supported on a tripod and gauze .

What does the flat region on the graph of temperature against time represent?

The point at 0 °C where the ice is melting — the beaker continues to be heated, but the thermal energy is used to break the bonds between particles rather than raising the temperature.

To avoid parallax errors, the thermometer should be read at ______ and held ______ in the beaker.

To avoid parallax errors, the thermometer should be read at eye level and held vertically in the beaker.

Why should the experiment only begin once the ice's temperature is below 0 °C?

To ensure the ice has not already started to melt, so the initial temperature readings are as accurate as possible.

True or False? The temperature of the ice increases steadily throughout the whole heating process.

False. The temperature increases at first, then stays constant while the ice melts at 0 °C, before rising again once melting is complete.

Why is the beaker, tripod and Bunsen burner set-up placed on a heatproof mat?

As a safety precaution, to avoid damage to the surface underneath from the heat of the Bunsen burner and beaker.

Define specific heat capacity .

The specific heat capacity , c , of a substance is the amount of energy required to raise the temperature of 1 kg of the substance by 1 °C, measured in joules per kilogram per degree Celsius (J/kg °C).

What does it mean if a substance has a low specific heat capacity, compared to one with a high specific heat capacity?

A substance with a low specific heat capacity heats up and cools down quickly (less energy is needed to change its temperature). A substance with a high specific heat capacity heats up and cools down slowly (more energy is needed).

What three factors affect how much a substance's temperature rises when heated?

The mass of the substance, the type of material (its specific heat capacity), and the amount of thermal energy supplied to it.

True or False? A substance with a high specific heat capacity heats up and cools down quickly.

False. A high specific heat capacity means a substance heats up and cools down slowly , because more energy is needed to change its temperature.

What is the aim of the core practical investigating specific heat capacity?

To determine the specific heat capacity of a solid (aluminium) and of water, by measuring the energy required to raise the temperature of a known mass by 1 °C.

What are the independent and dependent variables in this experiment?

Independent variable: time , t . Dependent variable: temperature , T .

The ______ of the graph of energy supplied against (mass × temperature change) gives the specific heat capacity of the substance.

The gradient of the graph of energy supplied against (mass × temperature change) gives the specific heat capacity of the substance.

True or False? The digital balance should be zeroed with the empty beaker on it before water is added.

True. Pressing 'zero' with the empty beaker on the balance ensures only the mass of the water is recorded once it is added.

Why is an average of the water's mass (before and after heating) used when calculating specific heat capacity?

To account for water lost to the surroundings through evaporation during heating.

Why should the gradient of the graph only be taken from the straight-line region, rather than from the very start?

Before that point, the energy supplied is being used to heat the immersion heater itself, not the water or solid block.

IGCSEPhysicsEdexcelPhysics (Modular)Unit 1Flashcards4. Solids, Liquids & Gases: Part 1Changes of State

Changes of State (Edexcel IGCSE Physics (Modular): Unit 1): Flashcards

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Define solid (as a state of matter).

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Cards in this collection (35)

Define solid (as a state of matter).
In a solid, particles are closely packed and vibrate about fixed positions. Solids have a definite shape and a definite volume.
Define liquid (as a state of matter).
In a liquid, particles are closely packed but can flow over one another. Liquids have no definite shape, but do have a definite volume.
Define gas (as a state of matter).
In a gas, particles are far apart and move randomly. Gases have no definite shape and no fixed volume.
Why are gases highly compressible, unlike solids and liquids?
There are large gaps between gas particles, so it is much easier to push the particles closer together than in a solid or liquid.
How does the energy of particles compare across the three states of matter?
Particles in a solid have the lowest energy, particles in a liquid have greater energy, and particles in a gas have the highest energy.
Particles in a solid vibrate about ______ positions, while particles in a liquid can ______ over one another.
Particles in a solid vibrate about fixed positions, while particles in a liquid can flow over one another.
True or False?
A liquid has a definite shape.
False.
A liquid has no definite shape — it flows and takes the shape of its container — but it does have a definite volume.
Define melting.
Melting is the change of state from a solid to a liquid. At the melting point, energy supplied is transferred to the particles' potential store, breaking the rigid bonds so they can flow over each other.
Define evaporation.
Evaporation is the change of state from a liquid to a gas that can happen at any temperature, not just the boiling point. Only the most energetic particles at the surface of the liquid have enough energy to escape the intermolecular bonds.
What are two differences between evaporation and boiling?
Evaporation can occur at any temperature, whereas boiling only occurs at the boiling point. Bubbles of gas form within the liquid during boiling, but not during evaporation.
Define internal energy.
The internal energy of a system is the sum of the kinetic energy of its particles (due to their motion) and the potential energy of its particles (due to their position relative to each other).
Why does the temperature of a substance stay constant while it is changing state, even though it is still being heated?
The energy supplied goes into the potential store of the particles, breaking the intermolecular bonds, while the kinetic energy of the particles — and therefore the temperature — stays constant.
The ______ of a substance is related to the average ______ of its molecules.
The temperature of a substance is related to the average kinetic energy of its molecules.
True or False?
During evaporation, bubbles of gas form throughout the liquid.
False.
Bubbles of gas form throughout the liquid during boiling. During evaporation, only particles at the surface escape — no bubbles form.
What is the aim of the core practical investigating changes of state?
To investigate how the temperature of ice varies as it changes state from a solid to a liquid, by heating it and recording the temperature at regular time intervals.
What equipment is used to heat and support the beaker of ice in this experiment?
A Bunsen burner heats the beaker, which is supported on a tripod and gauze.
What does the flat region on the graph of temperature against time represent?
The point at 0 °C where the ice is melting — the beaker continues to be heated, but the thermal energy is used to break the bonds between particles rather than raising the temperature.
To avoid parallax errors, the thermometer should be read at ______ and held ______ in the beaker.
To avoid parallax errors, the thermometer should be read at eye level and held vertically in the beaker.
Why should the experiment only begin once the ice's temperature is below 0 °C?
To ensure the ice has not already started to melt, so the initial temperature readings are as accurate as possible.
True or False?
The temperature of the ice increases steadily throughout the whole heating process.
False.
The temperature increases at first, then stays constant while the ice melts at 0 °C, before rising again once melting is complete.
Why is the beaker, tripod and Bunsen burner set-up placed on a heatproof mat?
As a safety precaution, to avoid damage to the surface underneath from the heat of the Bunsen burner and beaker.
Define specific heat capacity.
The specific heat capacity, c, of a substance is the amount of energy required to raise the temperature of 1 kg of the substance by 1 °C, measured in joules per kilogram per degree Celsius (J/kg °C).
What does it mean if a substance has a low specific heat capacity, compared to one with a high specific heat capacity?
A substance with a low specific heat capacity heats up and cools down quickly (less energy is needed to change its temperature). A substance with a high specific heat capacity heats up and cools down slowly (more energy is needed).
What three factors affect how much a substance's temperature rises when heated?
The mass of the substance, the type of material (its specific heat capacity), and the amount of thermal energy supplied to it.
The equation $Δ Q = m c Δ T$ states that the change in thermal energy equals mass multiplied by ______ multiplied by change in temperature.
The equation $Δ Q = m c Δ T$ states that the change in thermal energy equals mass multiplied by specific heat capacity multiplied by change in temperature.
State the equation used to calculate the change in thermal energy of a substance, defining each term and its unit.
$Δ Q = m c Δ T$
Where ΔQ = change in thermal energy (J), m = mass (kg), c = specific heat capacity (J/kg °C), and ΔT = change in temperature (°C).
True or False?
A substance with a high specific heat capacity heats up and cools down quickly.
False.
A high specific heat capacity means a substance heats up and cools down slowly, because more energy is needed to change its temperature.
What is the aim of the core practical investigating specific heat capacity?
To determine the specific heat capacity of a solid (aluminium) and of water, by measuring the energy required to raise the temperature of a known mass by 1 °C.
What are the independent and dependent variables in this experiment?
Independent variable: time, t. Dependent variable: temperature, T.
What type of electrical supply must the immersion heater be connected to, for safety?
A direct current (DC) supply.
How is the energy supplied by the immersion heater calculated at each time interval?
$Electrical energy = voltage \times current \times time$
using the voltmeter and ammeter readings recorded every 60 seconds.
The ______ of the graph of energy supplied against (mass × temperature change) gives the specific heat capacity of the substance.
The gradient of the graph of energy supplied against (mass × temperature change) gives the specific heat capacity of the substance.
True or False?
The digital balance should be zeroed with the empty beaker on it before water is added.
True.
Pressing 'zero' with the empty beaker on the balance ensures only the mass of the water is recorded once it is added.
Why is an average of the water's mass (before and after heating) used when calculating specific heat capacity?
To account for water lost to the surroundings through evaporation during heating.
Why should the gradient of the graph only be taken from the straight-line region, rather than from the very start?
Before that point, the energy supplied is being used to heat the immersion heater itself, not the water or solid block.

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