IGCSE Chemistry Terms

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Across
  1. 2. The average mass of the isotopes of an element compared to 1/12th of the mass of an atom of ¹²C.
  2. 4. A reaction where only one product is formed.
  3. 5. The water molecules present in hydrated crystals.
  4. 7. A solution containing the maximum concentration of a solute dissolved in the solvent at a specified temperature.
  5. 10. Different atoms of the same element that have the same number of protons but different numbers of neutrons.
  6. 11. A substance containing no water.
  7. 14. Coal, natural gas and petroleum.
  8. 15. A strong electrostatic attraction between nuclei of two bonding atoms and shared pair of electrons.
  9. 17. An acid that is completely dissociated in aqueous solution.
  10. 20. A liquid or solution that has passed through a filter.
  11. 22. The negative electrode where reduction takes place.
  12. 25. The net movement of particles from a region of their higher concentration to a region of their lower concentration (down a concentration gradient), as a result of their random movement.
  13. 31. A substance that reduces another substance and is itself oxidised.
  14. 33. Reactions involving simultaneous oxidation and reduction.
  15. 34. Gain of oxygen or loss of electrons/an increase in oxidation number.
  16. 37. A large molecule built up from many smaller molecules called monomers.
  17. 39. Loss of oxygen or gain of electrons/a decrease in oxidation number.
  18. 40. The number and type of different atoms in one molecule.
  19. 41. Metals that have high densities, high melting points, form coloured compounds, and often act as catalysts.
  20. 44. Has molecules in which one or more carbon-carbon bonds are not single bonds (e.g., C=C double bonds).
  21. 45. The total number of protons and neutrons in the nucleus of an atom.
  22. 48. The reaction between carbon dioxide and water to produce glucose and oxygen in the presence of chlorophyll and using energy from light.
  23. 49. A family of similar compounds with similar chemical properties due to the presence of the same functional group.
  24. 50. A substance that is chemically combined with water.
Down
  1. 1. An acid that is partially dissociated in aqueous solution.
  2. 3. The decomposition of an ionic compound, when molten or in aqueous solution, by the passage of an electric current.
  3. 6. A substance that dissolves a solute.
  4. 8. The minimum energy that colliding particles must have to react.
  5. 9. A substance that oxidises another substance and is itself reduced.
  6. 12. Compounds with the same molecular formula, but different structural formulae.
  7. 13. A substance that remains after evaporation, distillation, filtration or any similar process.
  8. 16. Has molecules in which all carbon-carbon bonds are single bonds.
  9. 18. A mixture of a metal with other elements.
  10. 19. The sum of the relative atomic masses. (Relative formula mass will be used for ionic compounds).
  11. 21. Compounds that contain hydrogen and carbon only.
  12. 23. The number of protons in the nucleus of an atom.
  13. 24. The transfer of thermal energy during a reaction. ΔH is negative for exothermic reactions and positive for endothermic reactions.
  14. 26. The electrostatic attraction between the positive metal ions in a giant metallic lattice and a 'sea' of delocalised electrons.
  15. 27. The positive electrode where oxidation takes place.
  16. 28. A substance that conducts electricity when it is in a molten (liquid) state or dissolved in water (aqueous solution) that undergoes electrolysis.
  17. 29. A strong electrostatic attraction between oppositely charged ions.
  18. 30. A reaction where one atom or group of atoms is replaced by another atom or group of atoms.
  19. 32. A substance that is dissolved in a solvent.
  20. 35. Oxides that react with acids and with bases to produce a salt and water.
  21. 36. The simplest whole number ratio of the different atoms or ions in a compound.
  22. 38. An atom or group of atoms that determine the chemical properties of a homologous series.
  23. 42. A mixture of one or more solutes dissolved in a solvent.
  24. 43. Proton acceptors.
  25. 46. Proton donors.
  26. 47. The unit of amount of substance; one mole contains 6.02 × 10²³ particles (e.g., atoms, ions, molecules); this number is the Avogadro constant.