IGCSE Chemistry Kinetic Theory and Diffusion Flashcards

Vocabulary flashcards covering particle arrangement, state changes, gas pressure, and diffusion from Cambridge IGCSE Chemistry notes.

Kinetic Theory of Matter

A model describing matter as consisting of tiny particles that are in constant motion.

Solid State

A state of matter where particles are packed very closely together in a fixed, regular pattern and vibrate in position without changing location.

Liquid State

A state of matter with a fixed volume where particles are close together but arranged randomly and move/slide past each other.

Gas State

A state of matter with no fixed volume where particles are far apart and move randomly and quickly at around $500\,m/s$ in all directions.

Melting Point

The specific temperature at which a solid absorbs thermal energy and transforms into a liquid.

Freezing Point

The specific temperature at which a liquid loses thermal energy and changes into a solid, occurring at the exact same temperature as melting.

Boiling Point

The specific temperature at which a liquid changes into a gas, where heat causes bubbles of gas to form below the liquid surface.

Evaporation

A change of state from liquid to gas that occurs only at the surface of liquids over a range of temperatures below the boiling point.

Condensation

A change of state from gas to liquid upon cooling over a range of temperatures as gas particles lose energy and group together.

Heating Curve

A graph showing how temperature and states change over time as thermal energy is absorbed by a substance.

Cooling Curve

A graph showing how temperature and states change over time as a substance loses thermal energy, serving as the mirror image of a heating curve.

Gas Pressure

The pressure produced inside a closed container by gaseous particles hitting the inside walls of the container.

Diffusion

The movement of particles from an area of high concentration to an area of low concentration due to random motion, requiring no energy input.

Reaction of Ammonia and Hydrogen Chloride

The reaction $NH_3(g) + HCl(g) \rightarrow NH_4Cl(s)$, where $NH_3$ ($M_r = 17$) diffuses faster than $HCl$ ($M_r = 36.5$), forming a white ring closer to the $HCl$ end.