Principles Of Chemistry Flashcards
Characteristics of a liquid
- close together but randomly arranged
- move around each other
- more energy than a solid
Characteristics of a gas
- very weak forces
- particles move in all directions and have more energy than a liquid
- arranged randomly
Solid liquid
Liquidgas
Solid—->gas
Melting , freezing
Condensing , BOILING
sublimation
Describe melting
When you heat a solid the energy makes the particles vibrate faster. Eventually they vibrate fast enough so that the forces of attraction are no longer strong enough to hold each other together
Describe freezing
If a liquid is cooled down its move slower until eventually they will be held in a regular arrangement
Describe boiling
When a liquid is heated strongly the particles have enough energy to break all forces of attraction
Describe condensing
If you cool a gas down the particles eventually move slowly and decrease in energy enough for the attractions between them to hold them in liquid form
What is evaporation
When a liquid turns to a gas at a temperature other than boiling point .particles move at different speed as they have different amount of energy
Describe sublimation
When a solid turn directly into a gas eg iodine
Define diffusion
The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient
Characteristics of a solid
- particles close together and held by strong bonds
- vibrating in fixed position
- arranged in a regular pattern
Two experiments for diffusion
1)jar of bromine - brown diffuses up
2)ammonia at one end , hcl on other
Ammonium chloride ring forms closer to hcl meaning it diffuses slower
The speed of diffusion takes place depends on….
The amount of energy the particles have …. Basically temperature
The mass of the particles diffusing ….heavier particles move slower
What are atoms made of
Protons , neutrons and electrons
What is a molecule
a group of two or more non-metal atoms joined together by covalent bonds
What are elements
Something that contains only one type of atom
What are compounds
A combination of two or more elements in a fixed ratio and joined by bonds
What are mixtures
Elements and compounds can also be mixed together as well as just the molecules . There is no fixed ratio or bonds so they are easy to separate
When would you use filtering
To separate insoluble particles from a liquid eg sand from water
When would you use evaporation (separation techniques)
To remove substances dissolved in a solution eg salt from salt water
when would you use distillation (separation techniques)
When you want the liquid in a solution and not the dissolved solid …. Or the liquid from a mixture of liquids
When would you use chromatography ?
Separation techniques
Separating a mixture of soluble substances
How to interpret chromatographs
The substance thats the most soluble with travel the furthest
What is fractional distillation
Two or more miscible (things that mix with another) liquids with different boiling points .the one with the lower boiling point evaporates faster and travels higher up then condenses in the condenser
