1. The fundamental ideas of chemistry Flashcards
What is the state change from solid to liquid?
Melting
Liquid to gas?
Evaporation
Gas to liquid?
Condensation
Solid to gas?
Sublimation
Gas to solid?
Sublimation
Features of a solids
Tightly arranged in a lattice Dense High intermolecular forces of attraction Vibrating Low energy
Features of liquids
Free flowing particles (ions)
Change the shape to that of the container
Randomly arranged
Slightly weaker intermolecular forces of attraction
Features of Gasses
Particles arranged randomly Move randomly filling the space Very weak/no intermolecular forces of attraction Not very dense (spaced out) free to move High energy
liquid to solid?
Freezing/liquefaction
(s)
Solid
(l)
liquid
(g)
gas
(aq)
in solution of water
How do you calculate percentage yield?
(actual mass made/expected mass) x 100
Why won’t you get 100% yield?
Reaction might be reversible
Product lost when it’s separated from reaction mixture
Impurities in reactants
Reactants might react in unexpected ways
What is Brownian motion and diffusion?
The theorem that fluid particles will spread out until they reach an even distribution
What is the link between temperature and rate of reaction?
Higher the temperature the higher the rate of reaction
What will diffuse faster, a more or a less dense gas?
The less dense gas
Which experiment proves particle theory?
The experiment with Ammonia (NH3) and HCl where a white precipitate is formed in a glass tube
What is an Atom?
The smallest indivisible particle
What is an Element?
A substance made of one type of atom chemically joined together
Found on the Periodic Table & represented by symbols
What is the relative charge and atomic mass of a Proton?
Relative charge = +1 Relative mass = 1
How do you calculate the percentage mass of an element in a compound?
(Ar x Number of atoms of the element) / (Mr of whole compound) x 100
E.g. Fe2O3
(16 x 3) / (56 x 2 + 16 x 3) x 100
30% Oxygen
How do you calculate the Empirical Formula, from masses or percentages?
experimental mass or percentage / Ar
Turn the numbers into a simple ratio
Get the ratio it its simplest form
How do you calculate the mass of substances in reactions?
Write out the balanced equations
Work out the Mr (for bits you want)
Divide to get one, then multiply to get all
What is the definition of diffusion?
It is the gradual movement of particles, from highly concentrated areas to areas of low concentration
Give three experiments to show diffusion
Potassium Mangante VII (KMnO4)
Place in beaker of water, purple colour will diffuse
Shows random motion of particles in a liquid
Br2 gas and air, brown colour will diffuse evenly
NH3 (aq) and HCl in tube, white ring formed
