1.1

Question 1

What are the three states of matter according to the OCR Gateway A specification for GCSE Chemistry?

Answer 1

Answer: Solids, liquids, and gases.

Question 2

Question: At what points do state changes occur?

Answer 2

Answer: State changes occur at the melting point (solid to liquid, liquid to solid) and at the boiling point (liquid to gas and gas to liquid).

Question 3

Question: What is the difference between melting/freezing and boiling/condensing in terms of state changes?

Answer 3

Answer: Melting and freezing occur at the melting point, while boiling and condensing take place at the boiling point.

Question 4

Question: When does evaporation occur, and at what temperature does it happen most rapidly?

Answer 4

Answer: Evaporation occurs at any temperature, but it happens most rapidly at the boiling point

Question 5

Question: How are the three states of matter represented in a simple model according to the OCR Gateway A specification?

Answer 5

Answer: In the model, particles are represented by small solid spheres with different arrangements and movements for solids, liquids, and gases.

Question 6

Solid

Answer 6

Arrangement of particles: Regular arrangement
Movement of particles: Vibrate about a fixed position
Closeness of particles: Very close

Question 7

Liquid

Answer 7

Arrangement of particles: Randomly arranged
Movement of particles: Move around each other
Closeness of particles: Close

Question 8

Gas:

Answer 8

Arrangement of particles: Randomly arranged
Movement of particles: Move quickly in all directions
Closeness of particles: Far apart

Question 9

Question: What is a physical change in a substance according to the OCR Gateway A specification for GCSE Chemistry?

Answer 9

Answer: A physical change is a change that does not involve a change in the identity of the substance

Question 10

Question: How is a chemical change or chemical reaction defined?

Answer 10

Answer: A chemical change is a change in which one or more substances are converted into different substances

Question 11

Question: What are the substances that react in a chemical change called?

Answer 11

Answer: The substances that react in a chemical change are called the reactants.

Question 12

Question: What are the substances formed by a chemical change called?

Answer 12

Answer: The substances that are formed by the chemical change are called the products.

Question 13

Question: How do physical changes differ from chemical changes?

Answer 13

Answer: Physical changes involve changes in the forces between the particles of the substances, but the particles themselves remain the same, as do the chemical properties of the substance

Question 14

Physical Changes

Answer 14

Definition: Changes in the forces between particles without altering the substance’s identity or chemical properties.
Reversibility: Relatively easy to reverse.

Question 15

Interconversions:

Answer 15

Melting: Solid to a liquid
Boiling: Liquid to a gas (from below surface as well as at surface)
Freezing: Liquid to a solid
Evaporation: Liquid to a gas (at surface only)
Condensation: Gas to a liquid
Sublimation: Solid to a gas

Question 16

Chemical Changes:

Answer 16

Definition: Involves the conversion of one or more substances into different substances.
Reactants: Substances that undergo the chemical change.
Products: Substances formed by the chemical change

Question 17

Front of flashcard:
Question: What does the particle theory explain regarding changes in state of matter according to the OCR Gateway A specification for GCSE Chemistry?

Answer 17

Answer: The particle theory explains how matter changes state depending on the energy and forces present between the particles in the substance.

Question 18

Question: How does the amount of energy needed for state changes (e.g., solid to liquid, liquid to gas) depend on the strength of forces between particles?

Answer 18

Answer: The stronger the forces between the particles, the higher the energy needed for melting and boiling to occur

Question 19

Question: What happens to particles when a substance is heated, according to the particle theory?

Answer 19

Answer: When substances are heated, the particles absorb thermal energy which is converted into kinetic energy, causing them to vibrate more and eventually overcome intermolecular forces to change state

Question 20

Question: What are some limitations of the particle theory?

Answer 20

Answer: The limitations include considering all particles as small, solid, and inelastic, without considering differences between particles such as atoms, ions, or molecules, and neglecting to account for intermolecular forces between different particles in different substances.