topic 4 Flashcards
states of matter
-Matter is anything that has mass and occupies space. It occurs in 3 main states: solid, liquid & gas however there’s also Plasma where atoms have been ionized and form a mixture of free electrons & + ions
Gaseous state
-Particles are far apart & mve freely. Very week attractive force so they canmove independently
-No definite shape or volume.They expand to fill entire volume of container i.e takes shape of container
-Highly compressible because of the large spaces b/w particles. applied pressure = particles pushed together w/ much reistance
-Low densities compared to ther states because of large distances b/w particles
-exhibit random motion & collisions w: each other & bouncing off container walls. Collisions create pressue which is the force/area exerted by the gas on walls
-collisions are elastic meaning no loss of energy
-Kinetic theory for gas -constant & random motion/ av. k.e of gas is directly proportional to temp change
-e.g O2
ideal gases
Concept: Ideal gases are theoretical models used to simplify the behavior of gases under specific conditions.
Particle Model: Consists of numerous identical particles in constant, random motion.
Assumptions: Negligible volume of gas particles and no intermolecular forces.
Collisions: Particles collide elastically with each other and container walls.
Temperature: Proportional to the average kinetic energy of gas particles.
Real Gases: Deviate under high pressure or low temperature due to particle volume and intermolecular forces.
Gas Laws and the Ideal Gas Law:
Gas laws describe the relationships between the properties of
gases. 4 of them:
1.Boyle’s Law: States that at constant temperature, the volume of a gas is inversely proportional
to its pressure.
2.Charles’s Law: States that at constant pressure, the volume of a gas is directly proportional to
its temperature in Kelvin.
3.Gay-Lussac’s Law: States that at constant volume, the pressure of a gas is directly proportional
to its temperature in Kelvin.
4.Avogadro’s Law: States that equal volumes of gases at the same temperature and pressure
contain an equal number of particles.
mnemonic 4 triangle to remember first three rules : Cant These Guy Possibly Be Victorious
IDEAL GAS Law
The ideal gas law combines these laws and relates the pressure (P), volume (V), temperature (T), and
the number of moles (n) of a gas: PV = nRT where R(8.314 J/ mol.K) is the ideal gas constant
Liquid state
Particle Arrangement: Particles are close together but can move past each other.
Volume and Shape: Definite volume, takes the shape of its container.
Density: More dense than gases but less dense than solids.
Intermolecular Forces: Stronger than in gases but weaker than in solids, allowing for fluidity.
Surface Tension: Tendency to minimize surface area, leading to droplets and capillary action.
Viscosity: Resistance to flow, influenced by intermolecular forces and temperature.
Boiling and Melting Points: Have characteristic temperatures at which they boil (vaporize) and melt (solidify).
Examples: Water, ethanol, and oil are common examples.
Phase changes related to pressure and temperature, the phase diagram of water.
Phase changes occur when matter transitions between the solid, liquid, and gaseous
states. The phase changes that can occur are:
* Melting: The change from a solid to a liquid state.
* Freezing: The change from a liquid to a solid state.
* Vaporization: The change from a liquid to a gas state, which includes boiling and evaporation.
* Condensation: The change from a gas to a liquid state.
* Sublimation: The change from a solid directly to a gas state without passing through the
liquid state.
* Deposition: The change from a gas directly to a solid state without passing through the liquid
state
phase diagram of water illustrates the relationship between
temperature and pressure and the phases of water (solid, liquid, gas). shows. conditions under which water exists in each phase. At standard atmospheric pressure, water freezes at 0 degrees Celsius and boils at 100 degrees Celsius. The phase diagram also indicates the critical point,
which is the temperature and pressure beyond which the liquid and gas phases become
indistinguishable.
Solid state
Particle Arrangement:
Particles are closely packed in a regular, repeating pattern.
Vibrate around fixed positions due to thermal energy.
Volume and Shape:
Definite shape and volume.
Maintains shape and size in any container.
Density:
Generally more dense than liquids and gases due to close particle packing.
Intermolecular Forces:
Strong intermolecular forces (ionic, covalent, metallic, van der Waals) hold particles in fixed positions.
Melting Point:
Temperature at which a solid changes to a liquid.
Depends on intermolecular forces and pressure.
Crystal Structure:
Can have a regular, repeating pattern (crystalline solids) or lack a regular arrangement (amorphous solids like glass).
Examples:
Metals (e.g., iron), salts (e.g., sodium chloride), minerals (e.g., quartz), and ice (solid water) are common examples.
Types of crystalline solids
Crystalline solids can be classified into different types based on the
arrangement of particles the have true melting points and ordered structure , including:
- Ionic Solids: Composed of positively and negatively charged ions held together by
electrostatic forces. - Molecular Solids: Composed of individual molecules held together by intermolecular forces.
- Metallic Solids: Composed of a lattice of metal atoms held together by metallic bonding.
- Covalent Network Solids: Composed of a three-dimensional network of covalently bonded
atoms.
Solids can be classified as Amorphous in that case they are disordered structures with NO true
melting points
Sublimation and Lyophilization:
1.Sublimation: -process where a substance transitions directly from the solid phase to the gas phase without passing through the intermediate liquid phase.
-Occurs at temperatures and pressures where the substance’s vapor pressure exceeds its triple point pressure.
2. Lyophilization is a specific method of drying where frozen substances are dried under vacuum, allowing ice to sublime directly from solid to vapor/ Involves freezing the substance, reducing pressure to induce sublimation, and collecting the vapor in a condenser to form a dry product./ used for food preservation & pharmaceuticals (antibiotics)
