Chemistry Project

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Across
  1. 4. a substance formed by the chemical combustion of two or more elements in fixed proportion.
  2. 5. the natural cycle by which rocks are pushed upwards, then eroded, transported, deposited, and possibly changed into another type of rock by conditions of temperature and pressure – these rocks may then be uplifted to enter a new cycle.
  3. 7. a regular three-dimensional arrangement of atoms, molecules or ions in a crystalline solid.
  4. 9. a subatomic particle with negligible mass and a charge of – 1.
  5. 10. a process occurring at the surface of a liquid, involving the change of state from a liquid into a vapor at a temperature below the boiling point.
  6. 14. term that describes a liquid, which evaporates easily; it is a liquid with a low boiling point having only weak intermolecular forces between the molecules in the liquid.
  7. 17. the temperature at which a liquid boils, when the pressure of the gas created above the liquid equals atmospheric pressure.
  8. 18. a chemical reaction in which a substance reacts with oxygen – the reaction is exothermic.
  9. 23. a chemical reaction in which a compound is made from its elements.
  10. 24. a form of local atmospheric pollution found in large cities in which several gases react with each other to produce harmful products.
  11. 25. a substance that can be used as a source of energy, usually by burning.
  12. 26. term that describes a solute that dissolves in a particular solvent.
  13. 27. the solid substance that has dissolved in a liquid to form a solution.
  14. 28. a molecule containing two atoms.
  15. 29. the liquid that dissolves the solid substance to form a solution.
  16. 30. the change of a vapor or a gas into liquid; during this process heat is given out to the surroundings.
  17. 31. a condition under which gas bubbles are able to form within a liquid – gas molecules escape from the body of a liquid, not just from its surface.
  18. 32. a substance, which cannot be further, divided into simpler substances by chemical methods; all the atoms of this substance contain the same number of protons.
  19. 33. the central, densest part of the Earth composed mainly of iron and nickel; the outer core is molten and surrounds the solid, inner core, which exists at very high temperature and pressure.
  20. 38. atoms of the same elements, which have different numbers of neutrons in their nuclei: they differ in their mass (nucleon) numbers.
  21. 40. is the smallest particle of an element that can take part in a chemical reaction.
  22. 41. the process of forming crystals from a saturated solution.
  23. 42. rain which has been made more acidic than normal by the presence of dissolved pollutants such as sulfur dioxide and nitrogen oxides.
  24. 45. a gas or a liquid, they are able to flow.
  25. 46. a subatomic particle with a relative mass of 1 and a charge of +1 found in the nucleus of all atoms.
Down
  1. 1. anything which occupies space and has mass.
  2. 2. the harmful effects on the air, water and soil of human activity and waste.
  3. 3. the chemical reaction (a combustion reaction) by which biological cells release the energy stored in glucose for the use by the cell or the body; the reaction is exothermic and produces carbon dioxide and water as the chemical by-products.
  4. 5. materials we get from the environment to meet our needs.
  5. 6. formed when a substance dissolves into another substance.
  6. 8. mixtures of elements (usually metals) designed to have the properties useful for a particular purpose.
  7. 11. the direct change of state from solid to gas or gas to solid: the liquid phase is bypassed.
  8. 12. the temperature at which a solid turns into a liquid – it has the same value as the freezing point.
  9. 13. the result of paper chromatography run, showing where the spots of the samples have moved to.
  10. 15. a mixture containing small particles of an insoluble solid, or droplets of an insoluble liquid, spread (suspended) throughout a liquid.
  11. 16. the process in by which solid different fluids mix as a result of the random motions of their particles.
  12. 19. element, which shows some of the properties of metals and some of Non – metals; for example, boron and silicon.
  13. 20. the system by which water circulates around the Earth, involving various changes of state in the process; the driving force behind the water cycle is energy from the Sun.
  14. 21. a type of chemical reaction where a compound breaks down into simpler substances.
  15. 22. a device for converting polluting exhaust gases from cars into less dangerous emissions.
  16. 24. the chemical process by which plants synthesize glucose from atmospheric carbon dioxide and water: the energy required for the process is captured from sunlight by chlorophyll molecules in the green leaves of the plant.
  17. 25. fuels such as coal, oil and natural gas, formed underground over geological periods of time from the remains of plants and animals.
  18. 34. a technique employed for the separation of mixtures of dissolved substances, which was originally used to separate colored dyes.
  19. 35. elements in Group 7 of the Periodic Table – generally the most reactive group of non – metals.
  20. 36. the system by which nitrogen and its compounds, both in the air and in the soil, are interchanged.
  21. 37. the combining power of an atom or group of atoms.
  22. 39. the process of boiling a liquid and then condensing the vapor produced back into the liquid: used to purify liquids and to separate liquids from solutions.
  23. 41. the solid, outermost, layer of the Earth; it is not continuous, but subdivided into plates of continental or oceanic layers.
  24. 43. charged particles made from an atom, or groups of atoms, by the loss or gain of electrons.
  25. 44. a black, solid fuel formed underground over geological periods of time by conditions of high pressure and temperature acting on decayed vegetation.