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GCSE: Classifying Materials

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How to tell if something is ionic

  1. 1 Ionic compounds have strong electrostatic attractions between their positive and negative ions. These take a lot of energy to break, so will have a very high melting and boiling point.
  2. 2 Ionic compounds can conduct electricity when dissolved in solution as their ions are free to move and carry charge. When they are solids, however, their ions are held in a fixed lattice so they cannot move and conduct electricity.
  3. 3 Ionic compounds are soluble in polar solutions like water. They are insoluble in organic solvents like cyclohexane.
  4. 4 Ionic compounds all form crystal salts. If these are hydrated they will often be brightly coloured. If they are not hydrated they will usually be transparent or white.
  5. 5 Ionic compounds are made from metal cations bonding to non-metal anions in a giant lattice.

How to tell if something is a giant covalent

  1. 1 Giant covalent compounds are held together by incredibly strong covalent bonds. These take a lot of energy to break, so will have an incredibly high melting and boiling point.
  2. 2 Giant covalent compounds do not have anything to carry charge (such as ions or delocalised electrons) so will not conduct electricity. The exception to this rule is graphite, as this has delocalised electrons so can conduct.
  3. 3 Giant covalent compounds are insoluble in both polar and non-polar solvents. This is because their strong covalent bonds are too strong to be broken by the solvent.
  4. 4 The three main forms (allotropes) of carbon that are giant covalent compounds are diamond (a beautifully shiny rock), graphite (which looks like the tiles on our roofs) and fullerines. Fullerines have a “football” shape.
  5. 5 Apart from allotropes of carbon, the most commonly occurring giant covalent compound that crops up in exams is SiO2.

How to tell if something is a simple covalent

  1. 1 Simple covalent compounds are held together by weak van der Waals forces. These take little energy to break, so have a very low melting and boiling point.
  2. 2 Simple covalent compounds do not have anything that can carry charge (like ions or delocalised electrons), so they cannot conduct.
  3. 3 Simple covalent compounds are soluble in non-polar solvents, and insoluble in polar solvents like water.
  4. 4 Due to their low melting and boiling point, most simple covalent compounds are liquids or gases at room temperature. The halogens will give coloured gases- Cl is pale green, Br is orange, I is an almost black solid which sublimes to a purple gas.
  5. 5 Simple covalent compounds are made from a non-metal bonding to a non-metal.

  • Marked by Teachers essays 10
  • Peer Reviewed essays 15
  1. How Does Temperature Affect the Rate of Reaction Between Hydrochloric Acid and Sodium Thiosulphate

    Higher temperature is another, because it gives particles more energy and they move more, so collide more frequently. Prediction Based on my background information, I predict that with every 10�C increase in temperature, they time taken to obscure the cross will decrease by 4 seconds. Preliminary Work To find the most accurate way of recording results we conducted preliminary tests. We varied the amount of sodium thiosulphate compared to hydrochloric acid, but kept the total volume of the mixture at 60cm3. We went up in steps of 5cm3 along the hydrochloric acid column, and down in steps of 5cm3 along the sodium thiosulphate column.

    • Word count: 2003
  2. Plastics Friend or Foe

    An example will be plastic bottles or toys. It can also be made to be flexible like rubber and can be made into a silk-like fibre like nylon. Plastic is also a great material for insulating heat and electricity and is very safe and non-toxic in normal situations. There are so many types of materials that are plastic and so many functions that would be too long to list. Suffice to say that a plastic material can be manufactured to use in almost any situation. SIMPLICITY Plastic is an incredibly versatile material, but the process of manufacturing plastic is quite simple.

    • Word count: 2036
  3. Relationship between mass of MgO and its formula

    Hypothesis To continue with this experiment I will need theories to predict what will happen in this experiment and to prove them I will need to produce these theories, which should in the end correlate with my results. The law of constant composition states that every pure sample of a given compound has exactly the same composition. Composition basically means that it has a certain amount of atoms. So this means every substance has a certain composition and is always the same regardless of where it was made or where it's from.

    • Word count: 2589
  4. A practical study of the periodic table.

    Mass of each of the atoms shown above is approximately twice as big as their atomic number. This is thanks to number of protons (atomic number) and nucleons (mass number) in the nucleus. The ionisation energy increases with the group number increasing and period decreasing, however an exception of magnesium has to be marked. Hence, the ionisation energy of aluminium is smaller than that of silicon or phosphorus; the ionisation energy of magnesium is greater than that of calcium. Type of elements also differs in group.

    • Word count: 2012
  5. material science unit 2 task 2

    Also used to build cars and their body parts e.g. rims, doors, engines, body. Airplanes: landing gear assembly, fuselage, engine components. Key rings and key chains, jewellery, pins, screws. Pans and pots. Spoons and forks. The railway for trains, furnaces, hammers, screwdrivers, drill parts, chain saw blades. Magnets. Pure metal elements: zinc, copper, iron, aluminium, gold, silver etc... Alloys: Brass (made from Cu and Zn), steel (Fe and C), solder (made from Pb and Sn). Ceramics: glass pottery and china Composition Their atoms are held closely together. Ceramics are compounds of oxygen. (Oxides) but some are also nitrides (nitrogen compound); carbides (carbon compounds), borides (compounds of boron) and the rest are Silicides (silicon compounds).

    • Word count: 2052
  6. Specific Heat Lab

    cmetal= (.40005*4180*1.50)/(.05345*79.60) cmetal= (2511.135)/(4.25462) cmetal= 589.55 To find the percentage error for our specific heat we use the following formula: |Accepted Value - Our Value | / (Accepted Value * 100) |380 - 589.6| / 380 * 100 209.5/38000 55.14% The error for Brass on our first trial is 55.14% To find the uncertainties in our measurement we reorder the following formula Error Q / q = (Error a/a + Error b/b...) to Error Q = (Error a/a + Error b/b...)*q.

    • Word count: 2109
  7. Determination of the relative atomic mass of lithium

    & burette * 100cm3 distilled water * Phenolphthalein indicator * Measuring scale- (must make sure that the measurements taken is to 2 decimal places) AWARENESS IN CARRYING OUT THE EXPERIMENT It is important that my delivery tube stays under water to avoid gas bubbles forming in it, and it is possible that the delivery tube might not fit into the bung very well because of its length, so make sure that the delivery tube stays the same trough and remains the same throughout the experiment.

    • Word count: 2323
  8. An experiment to show how the amount of zinc oxide produced is affected by the amount of calamine used.

    The graph I expect to obtain is similar to the one I have drawn below. It show clearly that as the mass of calamine used increases so does the mass of zinc oxide. For the actual experiment I intend to take five readings or measurement for five different amounts of calamine. Once I have completed my experiment I will repeat it using the exact same procedure allowing me to have two sets of results which I can then use to calculate an avearage and dicplay my results visualy. Obstaining Evidence Plan: To see if my prediction is correct I will need the following apparatus to perform the experiment: � Test tubes � Test tube rack

    • Word count: 2135
  9. The Structure of the Atom.

    Simple Diagram of an Atom : The Sodium atom. The first electron shell (closest to the nucleus) can contain at most 2 electrons. The second electron shell can contain at most 8 electrons. The third electron shell can contain, at most, 18 electrons. As a general rule electrons occupy the lowest available electron shell. As the number of negative charges (electrons) balances against the number of positive charges (protons) the sodium atom has no overall charge. Q1. Define the following terms : Atomic number, Mass No, Relative atomic mass, isotope.

    • Word count: 2240
  10. Investigation on the combustion of Alcohols.

    This energy diagram is for an exothermic reaction. It shows the energy content of the reactants and the products. The energy change for a reaction delta H can be calculated using bond energies ?H = (sum of bonds being broken) - (sum of the bond being made) Bond energy is defined as the energy required to break one mole of bonds in a substance in the gaseous state. Bond Bond energy in KJ/Mol C-C 348 C-H 412 C-O 360 O-H 463 O=O 496 C=O 743 H-H 436 Apparatus Thermometer Measuring cylinder (100cm2)

    • Word count: 2104
  11. Identification of an unknown compound.

    The reagents used in the chemical tests require additional precautions. For example, when using bromine water to test for the presence of a phenol, the fume cupboard should be used due to the strong smell of bromine. Chemical tests An outline of how to carry out each chemical test is described below: Test 1: Phenol Pipette 2 ml of bromine water into a test-tube. Add to this a few drops of the sample and gently shake. For a positive result the bromine water decolourises and a white precipitate forms, indicating a phenol is present and therefore it is not necessary to carry out further chemical tests.

    • Word count: 2744
  12. Variability of Relative Stability of Oxidation States.

    The principal product of the reaction of the alkali metals with oxygen varies systematically down the group. It is commonly found that ionic compounds formed from cations and anions of similar radius radii. Such is the case here. Lithium forms mainly the oxide, Li2O. Sodium, which has a larger cation, forms predominantly the pale yellow sodium peroxide, Na2O2. Potassium, with an even bigger cation, forms mainly the superoxide, KO2, which cations the superoxide ion, O2-. Therefore, +1 is the most stable oxidation state for the group(I) chemistry. Although 0 is one of the oxidation states, yet those elements are very active and tend to react with O2 and some oxidation reagents.

    • Word count: 2437
  13. Investigating the energy change when zinc reacts with copper(II) sulphate.

    Endothermic reactions are to produce more stable compounds. Evidence for an endothermic reaction taking place, is a cold test tube. Variables. The factor that I will be changing during this reaction is the amount of zinc I will be using. The maximum amount of zinc I am allowed to use is 0.5g due to environmental issues. I will be using powdered zinc instead of blocks of zinc is because of two reasons: * It will be easier to weigh an accurate amount of zinc better because of the small amount that we are allowed to use.

    • Word count: 2016
  14. An Investigation Into How the Mass of Zinc Effects the Heat Change In the Displacement Reaction Between Zinc and Copper Sulphate.

    To do this I will have to measure the initial and final temperature of the reaction. Hypothesis I expect that the investigation will show that an increase in the mass of zinc will cause an increase in the heat change, and therefore the temperature change. This is because a doubling in the amount of zinc would mean that there would be twice as many particles within the mass, therefore there will be twice as many collisions with the copper sulphate particles.

    • Word count: 2029
  15. Decomposition of copper carbonate - proving one of two equations.

    For an element, the mass of 1 mole is the same as the atomic mass in grams. For a compound the mass of one mole is the same as the relative formula mass or molecular mass in grams. The molecular or formula mass of a compound is found by adding the relative atomic masses of its constituent elements, as found in the periodic table. Substance Mr/Ar - and hence, mass of 1 mole (g) Copper Carbonate (CuCO3) 123.5 Copper Oxide (Cu2O) 143 Copper Oxide (CuO) 79.5 Carbon Dioxide (CO2) 44 Oxygen (O2) 32 So using the equation of a reaction, it is possible to predict the masses of products that will be made by a given mass of reactants.

    • Word count: 2390
  16. Ions - a qualitative analysis on our chemicals by flame testing.

    Aim We are going to carry out a qualitative analysis on our chemicals by flame testing. This process will be carried out by burning an ionic substance into a combustion flame. The results will be recorded by the visual aid of the flame changing colour the test will be carried out on seven unidentified materials. By carrying out the flame test I hope to acquire the skill of flame testing and how to recognised cat ions and anions I also aim to carry this experiment out with a high level of accuracy.

    • Word count: 2954
  17. Investigating how much energy is produced when burning alcohols.

    The first could be ionic, where a metal is produced. Ionic bonding involves electrons transferring from one atom to the other consequently leaving an electrostatic force between them. The other form of bonding is covalent where atoms share electrons to complete their outer orbit. An example being Methane where four hydrogen atoms each share an electron with a carbon atom. Hypothesis My hypothesis for this experiment is that as the amount of atoms in the alcohols increase, so will the amount of energy per mole. Prediction I predict that the more bonds there are holding the carbon, oxygen and hydrogen atoms together; more energy will be required to break them apart.

    • Word count: 2132
  18. Gravimetric Determination of Phosphorus in Plant Food

    Phosphorus will be determined by precipitation of the insoluble salt magnesium ammonium phosphate hexahydrate according to the reaction: 5H2O(l) + HPO42(aq) + NH4+(aq) + Mg2+(aq) + OH-(aq) → MgNH4PO4 · 6H2O(s) The %P and %P2O5 in the initial sample can be calculated from the mass of MgNH4PO4 · 6H2O(s) obtained using the following method: mass of MgNH4PO4 · 6H2O(s) → moles of MgNH4PO4 · 6H2O(s) → moles of P → mass of P → %P and mass of MgNH4PO4 · 6H2O(s) → moles of MgNH4PO4 · 6H2O(s) → moles of P → moles of P2O5 → mass of P2O5 → %P2O5 In a gravimetric analysis one utilizes a property of certain species that they precipitate (i.e., form an insoluble solid product)

    • Word count: 2477

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