Across
- 4. a chemical compound containing only hydrogen and carbon.
- 5. articulates small particles of carbon made during incomplete combustion also known as soot.
- 11. how easily a material is rolled out into a sheet without breaking.
- 15. mistakes in results due to human judgement or poor control of variables.
- 16. a solution that contains as much dissolved solid as it possibly can.
- 17. a reaction displayed using the chemical symbols of the substances involved.
- 18. a common acid.
- 20. a reaction in which new substances are made.
- 23. chemical reaction where a substance is broken down into at least two new substances when heated.
- 26. the process by which a solid forms, where the atoms or molecules are highly organised into a structure known as a crystal.
- 29. material which light can travel through.
- 31. combustion with a very limited supply of oxygen, that produces carbon particulates and water.
- 35. a chemical that can break up large molecules.
- 36. red or blue paper used to test for acids and alkalis.
- 37. a substance containing two or more elements that are not chemically joined.
- 43. produces a ringing sound when hit.
- 44. caused by excess acid being produced in the stomach and escaping to areas where cells are not protected from it.
- 47. a chemical that changes colour depending on how acidic or alkaline a liquid is.
- 49. combustion with a limited supply of oxygen, that produces carbon monoxide and water.
- 50. a common acid. Used in car batteries.
- 51. alkali pH 11 – 14.
- 53. a chemical which speeds up the rate of a reaction without being used up in the reaction.
- 54. a base that dissolves in water.
- 58. easily broken.
- 59. when a liquid turns into a gas.
- 64. a part, share, or number considered in comparative relation to a whole.
- 66. a mixture of indicators giving a different colour depending on how weak or strong an acid or alkali is.
- 68. liquid liquid that is red in acids, purple in neutral and blue in alkalis.
- 69. the useful product in a chemical reaction.
- 70. a reaction between an acid and a base (or alkali) that makes a solution with a pH of 7. A salt and water are produced.
- 71. an exothermic reaction that gives out lots of energy or a reaction that produces a gas very quickly making lots of bubbles. If the gas is flammable, it could ignite or be explosive.
- 72. how easily a material is drawn out into thin wire without breaking.
- 74. something that is used to describe how a material behaves and what it is like. Strength is a property of some solids.
- 75. a way of describing a reaction using chemical formula showing the correct numbers of molecules involved to show conservation of mass.
- 76. a process or reaction that releases energy from the system to its surroundings, usually in the form of heat or light.
- 78. pH 8 – 10.
Down
- 1. when a shiny metal gets a dull coating due to the reaction with oxygen.
- 2. the acid in vinegar.
- 3. something that irritates the skin and eyes.
- 6. reaction of a substance with oxygen to produce a compound containing oxygen (oxygen has been ‘added’ to the original substance).
- 7. substances that attack metals, stonework and skin are called corrosive.
- 8. chemicals in a mixture that are undesirable.
- 9. symptoms such as pain in the chest.
- 10. contains OH e.g. sodium hydroxide NaOH.
- 12. a burning reaction, when a fuel combines with oxygen and releases energy.
- 13. mass is not created or lost in a chemical reaction.
- 14. substance that is neither an acid nor an alkali. It has a pH of 7.
- 19. a solid chemical that reacts with an acid to form a salt and water.
- 21. the smallest part of an element.
- 22. weak acid in some insect stings.
- 24. a chemical compound that contains one carbon atom and three oxygen atoms (CO3).
- 25. safe to eat.
- 27. pH 0 – 3.
- 28. the strong force of attraction holding atoms together in a molecule.
- 30. when a gas is being given out, bubbling and fizzing is observed.
- 32. too much of something.
- 33. treat acidic soil with lime to increase the pH and ensure better growth of certain crops.
- 34. a compound made when acids react with metals or bases. Many salts are chlorides, sulphates or nitrates. Common salt is sodium chloride.
- 38. a machine to measure pH in solutions, reduces random errors and can determine pH to decimal numbers.
- 39. a common acid that is found in your stomach.
- 40. substances that can be split into simpler substances.
- 41. chemicals that form new substances during a chemical reaction.
- 42. solution pH > 7, formed when an alkali dissolves in water.
- 45. iron oxide – a flaky red compound formed when iron reacts with oxygen.
- 46. a substance that turns litmus red. It has a pH of less than 7.
- 48. un unfavourable circumstance or condition that reduces the chances of success or effectiveness.
- 52. a toxic molecule that binds irreversibly with red blood cells and stops them carrying oxygen.
- 55. anything that stores energy that can be converted into heat energy, e.g. fossil fuels and nuclear fuels.
- 56. chemical reactions to aid in the manufacturing of an item or items, usually carried out on a very large scale.
- 57. a reaction displayed in words.
- 60. a new chemical formed in a chemical reaction.
- 61. a substance that cannot be split up into anything simpler by chemical reactions. All the atoms in an element are the same.
- 62. the set of metallic elements occupying the central block of the periodic table.
- 63. unable to be bent or forced out of shape.
- 65. does not have a smell.
- 67. a chemical reaction that takes in energy from the surroundings (often heat), leading to a fall in temperature.
- 73. the acid in citrus fruits.
- 77. pH 4 – 6.