Kinetic Theory and Diffusion Flashcards
What are the properties of solids?
- Strong forces of attraction between particles holding the particles are close together in a fixed positions to form a very regular lattice arrangement
- Cannot move, only vibrate in a fixed position, the hotter the solid becomes the more they vibrate (causing solids to expand slightly when heated)
- Arranged in a regular pattern
- Cannot be compressed
- Definite shape and volume
- Dense
What are the properties of liquids?
- Weak force of attraction between particles
- Particles are close together
- Can move around/past each other
- Arranged in a random way
- More energy than in a solid
- Cannot be compressed easily
- Definite volume but do not keep a definite shape and will flow to fill the bottom of a container
- The particles are constantly moving with a random motion, the hotter the liquid gets the faster they move. This causes liquids to expand slightly when heated
What are the properties of gases?
- The force of attraction between the particles is very weak they are free to move and are far apart
- Arranged in a random way and can move quickly in different directions, the particles in gases travel in straight lines
- More energy than a liquid or solid
- Do not keep definite shape or volume and will always fill any container
- Particles move constantly with random direction, the hotter the gas gets, the faster they move. Gases either expand when heated, or their pressure increases
What is a solid to a liquid?
- Melting
- When a solid is heated, its particles gain more energy
- This makes the particles vibrate more which weakens the forces that hold the solid together
- This makes the solid expand
- At a certain temperature the particles have enough energy to break free from their positions
What is a liquid to a gas
- Evaporating
- When a liquid is heated the particles get even more energy and this energy makes the particles move faster, which weakens and breaks the bonds holding the liquid together
- At a certain temperature the particles have enough energy to break their bonds
What is a gas to a liquid
Condensing
What is a liquid to a solid
Freezing
What is a solid to a gas or a gas to a solid?
Sublimation
What is an element?
A substance made up of only 1 type of atom
E.G copper
What is a compound?
A substance made up of two or more different elements chemically bonded together in fixed proportions
E.G H20 NH3 NaCl
What is a mixture?
A substance made up of 2 or more components not chemically bonded together E.G Air, Sea water, Crude oil, Bronze
What is diffusion?
- Diffusion is the random movement of particles from an area of high concentration to an area of low concentration
- Gases diffuse quicker than liquids
- The lighter the molecule (H2) the faster it will diffuse than a heavier molecule (Br2)
- Hotter temperature faster rate of diffusion
Describe the experiment between bromine and air
- Fill half a gas jar full of brown bromine gas and the other half full of air and separate the gases with a glass plate
- When the glass plate is removed the brown bromine gas slowly diffuses through the air
- The random motion of the particles means that the bromine will eventually diffuse right through the air, and the bromine particles and air particles bounce around at random to give an even mixture
What experiment shows that particles in different gases travel at different speeds?
- Bits of cotton wool are soaked in concentrated ammonia solution (as a source of ammonia gas) and concentrated hydrochloric acid (as a source of hydrogen chloride gas)
- These are placed at the ends of a long glass tube with rubber bungs to stop the poisonous gases escaping
- Depending on the length and diameter of the glass tube, eventually a white solid ring of ammoniuM chloride will form closer to the HCL cotton wool
What do the results of the ammonia and HCL experiment show?
- Therefore the ammonia gas particles have travelled further faster the the ammonia particles are LIGHTER than the hydrogen chloride particles.
- Thus light particles are faster than heavier particles