Structure 1.1 Flashcards
(47 cards)
What are elements?
Primary constituents of matter, they cannot be chemically broken down into simpler substances
Chemical Element
A neutral substance that cannot be chemically broken down into simpler substances. It consists of only atoms that contain the same number of protons.
Compound
A pure substance occurring when two or more chemical elements are chemically bonded together. It has different properties from its component elements.
Solids
Occupy a fixed space and volume. Particles held closely together in a lattice.
Liquids
Fixed volumer that takes the shape of its container. Particles are close together but move with random motion.
Gases
Completely fill their container particles are widely spaced and move with rapid random motion.
Heat
A measure of the total amount of energy in a given amount of substance. Depends on the amount of substance present. Measured in Joules (J)
Temperature
The measure of the average kinetic energy or ‘hotness’ of a substance. Independent of the amount of substance present. Measured in Kelvin.
What happens at 0K?
All motion has stopped. Absolute zero
Litre to Meter conversions
mL=cm^3
L=dm^3
When do liquids boil?
When their vapour pressure equals atmospheric pressure. Lowering/raising will lower/raise the boiling point.
Melting
Changing from a solid to a liquid
Freezing
Changing from a liquid to a solid
Vaporisation
Changing from a liquid to a gas
Evaporation
Changing from a liquid to a gas below the boiling point
Boiling
Changing from a liquid to a gas when the vapour pressure equals the external pressure
Condensation
Changing from a gas to a liquid
Sublimation
Changing from a solid to a gas without going through a liquid state
Deposition
Changing from a gas to a solid without going through the liquid state
What is the arrangement of particles in the solid state?
In the solid state, particles are closely held together in a fixed position within a lattice structure. They can vibrate about a fixed point.
What happens to solid particles as heat is supplied?
As heat is supplied, the vibration of particles intensifies. Eventually, they gain enough energy to break the lattice structure, and the particles become free to move, entering the liquid state.
What is the liquid state in terms of particle behavior?
In the liquid state, particles are free to move, but there are still attractive forces between them. The particles have more energy than in the solid state but are not completely free.
How do particles behave as more heat is added to a liquid?
As more heat is added, particles move faster and gain kinetic energy. Eventually, they have enough energy to overcome attractive forces and escape as vapor.
What is the boiling point, and how does it relate to external pressure?
The boiling point is when the vapor pressure equals the external pressure. The boiling point depends on the external pressure. For example, at 100 kPa, water boils at 373 K (100°C).
