eoy rev. topics

• what is the arrangement, movement and energy of the particles in a solid?

  the arrangement is regular, there is little movement (vibration) and there is little kinetic energy
• what is the arrangement, movement and energy of the particles in a liquid?

  the arrangement is random, taking the shape of the bottom of their container, they move around freely - sliding on top of each other - and there is more kinetic energy than a solid.
• what is the arrangement, movement and energy of the particles in a gas?

  the arrangement is random and scattered, there is fast, random movement and there is a lot more kinetic energy than a liquid and a solid.
• what are the interconversions between the states of matter?

  melting, freezing, boiling, condensing, sublimation (solid to gas), de-sublimation (gas to solid)
• what is meant by the term diffusion?

  diffusion is movement of particles from a region of higher concentration to a region of lower concentration due to their random movement.
• why is diffusion typically a slow process - even when particles move at very high speeds?

  diffusion is a typically slow process due to collisions with particles of air or water.
• why do different substances diffuse at different speeds?

  different substances diffuse at different speeds due to the mass of the particles.
• describe and explain what happens when liquid bromine is added to a glass jar.

  the bromine particles start to diffuse and rise from high concentration to low concentration until the particles are evenly spread throughout the jar.
• describe and explain what happens during the 'white ring' experiment.

  the ammonia particles and the hydrogen chloride particles react, creating a white ring. this ring appears nearer to the ammonia gas - because the particles are heavier, and therefore diffuse slower.
• what is meant by the term dissolving?

  dissolving is when the particles of a soluble substance get broken down by the particles in a solvent - and then combine.
• explain the words solute, solvent, solution, soluble and insoluble.

  solute - a solid that dissolves in a solvent

  solvent - a liquid that breaks down a solute

  solution - the product of a solute broken down and combined with a solvent

  soluble - a substance that dissolves in a solvent

  insoluble - a substance that will not dissolve in a solvent (even after mixing)
• how does filtration separate mixtures of substances?

  filtration separates an insoluble solid from a liquid eg. sand and water: the sand would stay behind in the filter paper whilst the water goes into the beaker.
• how does evaporation (crystallization) separate mixtures of substances?


  the solution is heated and the solvent evaporates, leaving behind the solute that was previously dissolved. eg. salt and water.
• how does distillation separate mixtures of substances?

  distillation separates the solute and the solvent, keeping the liquid (solvent). distillation involves boiling the solution and then condensing the vapour back into a liquid by cooling it down.
• state the laboratory equipment needed for filtration and evaporation:

  filtration: beaker, filter paper, funnel,

  evaporation: bunsen burner, tripod, (wired) gauze, 'evaporating basin' - check term
• state the changes of state that occur during distillation and the location where they occur on the apparatus.

  boiling/evaporation: the mixture boils/evaporates in the distillation flask

  condensation: the vapour condenses on the cool surface of the 'condenser' - check term

  
• how can chromatography be used to determine the number and type of substances present in a mixture?

  because substances have different Rf values, you can use chromatography to identify the different substances present in a mixture by comparing their Rf value to their published values (either given or in a data book).
• how do you figure out the Rf value of a substance on a chromatogram?

  Rf values can be calculated with the equation distance moved by substance / distance moved by solvent. make sure to measure from the baseline where the substance was originally applied to where the center of the substance spot is now.
• what is an element?

  a substance in which the atoms are all the same (one type of atom, same atomic number)
• what is the atomic number in regards to an atom?

  the atomic number, in regards to an atom, is the number of protons found inside of it (and number of electrons, not added together).
• what is the relative atomic mass in regards to an atom?

  the number of protons + neutrons in total.
• how are the atoms organised on the periodic table?

  atoms are organised in order of increasing atomic number
• where are the groups and periods located on the periodic table

  groups are the columbs, with the group labels going across - whereas the periods are in rows, with the period labels going vertically.

  
• where is the dividing line on the periodic table?

  the line starts beneath boron and essentially descends in a stair-like manner - going across boron and then descending. it ends before astatine

  
• where are the metals and non-metals on the periodic table located?

  the metals are located on the left of the dividing line, and the non-metals on the right.
• what do elements in the same group have in common?

  they all have similar chemical properties.
• what are sub-atomic particles?

  protons, neutrons and electrons
• what is the location, relative charge and relative mass of a proton?

  location: nucleus

  relative charge: +1

  relative mass: 1
• what is the location, relative charge and relative mass of a neutron?

  location: nucleus

  relative charge: 0

  relative mass: 1
• what is the location, relative charge and relative mass of a electron?


  location: shells

  relative charge: -1

  relative mass: 1/2000 (negligible)
• what is meant by the term 'atomic number' in terms of sub-atomic particles?

  the atomic number is the number of protons in that element (and electrons, but not in total)
• what is meant by the term 'mass number' in terms of sub-atomic particles?

  the mass number is the number of protons added to the number of neutrons.
• what is meant by the term 'isotopes'?

  two atoms of the same element that have the same number of protons, but a different number of neutrons, therefore having a different atomic mass (not relative atomic mass) and the same atomic number.
• what is meant by the term relative atom mass (to do with isotopes)

  the relative atomic mass is the weighted average mass of all the isotopes of an element on a scale.
• how do you calculate the relative atomic mass of an element from the percentage abundances of each isotope?

  (1st mass number x abundance) + (2nd mass number x abundance)/100. eg. if there are 92 7/3 Lithium particles and 8 6/3 Lithium particles, the calculation would be (92x7)+(8x6)/100 = 6.92 which is the average of one Lithium particle.
• how do you deduce the electronic configurations of the elements with an atomic number of 1-20 (Hydrogen to Calcium)?

  the first 4 shells can contain 2,8,8 and 2 electrons in each shell (20 max. total) and you simply put arrange your atomic number in these shells. eg. if the atomic number is 18, the electronic configuration would be 2,8,8.
• what is a compound?


  a substance that contains two or more elements/types of atom that have chemically combined/bonded
• what happens to atoms in chemical reactions?

  the atoms rearrange to create new substances
• what happens to the total mass of reactants and products in a chemical reaction?

  the total mass is the same (conversion of mass) for example in the reaction of magnesium with oxygen to form magnesium oxide.
• what does a compound contain?

  a compound contains atoms of different elements that are bonded together in a fixed ratio and this can be represented in a chemical formula