Summary
Summary Chemistry
This is a 90 page long document - consisting of my notes, notes from tutors and also notes Ive made with friends throughout the course. Its in detail and super simple to understand.
[Show more]
Seller
Follow
Content preview
ChemistryPrinciples of Chemistry
States of matter
• Solids
o Have a fixed shape and volume (particles are fixed into place)
o Cannot be compressed (barely space between particles)
o Don’t flow easily (Particles cant get past eachother)
• Liquids
o Particles in a liquid vibrate and are able to move about as they have
more energy than the particles in a solid
o Take the shape of their container but have a fixed volume
o Not easily compressed (not much free space between particles)
o Flow easily (particles can move past eachother)
• Gases
o Have the most energy and vibrate and move freely at high speeds
o Take the shape and volume of the container – gases expand to fill the
space available
o Easily compressed (lots of space in between particles)
o Flow easily
Changing state
• Solid to liquid (melting)
o Heat a solid – particles gain (kinetic) energy and start to vibrate faster
and faster until the forces of attraction holding them together start to
break & solid melts to become a liquid.
o Melting point = temperature needed to turn a solid to liquid
• Liquid to solid (freezing)
o Liquid cools, the particles lose energy and so they slow down until they
are slow enough for the forces of attraction between them to hold them
together causing the liquid to freeze and become a solid.
o Freezing point = temperature needed to turn a liquid to a solid
• Liquid to gas (boiling or evaporation)
o Boiling concerns the whole liquid, evaporation concerns the particles at
the surface of a liquid.
o Boiling = heat a liquid strongly the particles gain (kinetic) energy and
move around faster until all the forces of attraction holding them
together break and the particles become free to move and the liquid
boils.
▪ Boiling point = temp needed to turn a liquid to a gas
o Evaporation = at any given temperature, particles will be moving at
different speeds. On the surface of a liquid, some of the very fast
particles will have enough (kinetic) energy to be able to break away
and ‘escape’ from the liquid to become a gas.
, • Gas to liquid (condensation)
o Gas cools, the particles move slower and slower until eventually they
are slow enough for forces of attraction to hold them together causing
the gas to condense and become a liquid
• Solid to gas (sublimination)
o Some substances can change directly from a solid to a gas without
becoming a liquid in between.
Atoms
• DEFINITION : Atom = the basic unit of matter – the simplest unit that a
substance can be broken down into. Very small.
• To investigate how small particles are we use dilution experiments.
How do particles move
• Brownian motion
o Discovered by botanist Robert Brown in 1827
o Random movement of particles in a liquid or a gas is because the
particles are bumping into each other as they move.
• Particles like to have room to move – so they’ll move from an area where they
are highly concentrated to an area of lower concentration (more room to
move)
• DEFINITION: Diffusion = the movement of particles from an area where they
have a high concentration to an area where they have a lower concentration,
results in spreading out of particles
o Both gases and liquids can diffuse, but gases diffuse much faster and
easier than liquids.
Demonstrating diffusion in gases
• Show diffusion using two gas jars
, o Bromine gas is an orangey/brown coloured gas. When we take the lid
away, the brown colour diffuses upwards and the colourless air
particles moves downwards until both jars contain the same amount of
bromine & are the same colour.
• Not all gases travel at the same speed.
o Gas particles have different masses
o Reaction between ammonia and hydrogen chloride gas can show this :
▪ Tube is sealed at both ends to stop poisonous gases escaping.
▪ A white ring forms inside the tube but the ring is closer to the
hydrochloric acid soaked cotton wool. This shows us that the
ammonia has travelled faster than the hydrogen chloride gas.
Demonstrating Diffusion in Liquids
• Liquids diffuse slower than gases.
• Can be shown using a strongly coloured solution and water. Eventually the
colour will spread through the water when added, this will show the diffusion
of the water particles and solution.
Atoms & Molecules
• DEFINITION: Molecule = atoms that are joined together by chemical bonds
• DEFINITION : Diatomic molecule = when 2 of the same atom are bonded
together to make a molecule e.g. H2
Elements, Compounds & mixtures
• DEFINITION: Element = substances that cant be broken down into anything
simpler because the are made up of only one type of atom
• DEFINITION: Compounds = when two or more different elements combine by
forming a chemical bond
• DEFINITION: Mixture = when elements or compounds combine without
forming a chemical bond
o Each component can be present in variable proportions
o Each component still keeps its own properties
o Can be separated by physical means
, Compound Mixture
Fixed/same amount of each element Varied amounts of each element
Have different properties from the Mixtures have the properties of each
elements substance in the mixture
Forming usually results in an energy Forming results in small or no energy
change changes
Elements not easily separated; only Easily separated; separated using
separated by chemical means physical means
Separating mixtures
• Can be separated by physical means such as changing the temperature or
dissolving part of the mixture.
Filtration
• DEFINITION: Filtration : separating an insoluble solid from a liquid or solution.
o Filter the mixture through filter paper, the solid stays on the paper and
the liquid passes through.
Simple Distillation
• DEFINITION: Simple distillation = used to separate two solids, where on is
soluble in water and one is not.
• DEFINITIONS :
o Solute = a substance that dissolves in a solvent forming a solution
(usually a solid)
o Solvent = a substance in which a solute dissolves forming a solution
(usually a liquid)
o Solution = a uniform mixture which is formed when a solute is dissolved
in a solvent
o Saturated = When no more solute will dissolve into the solution and
can be seen floating in the liquid.
Look at notes for others
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller robynatherton1. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £10.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
81989 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now