Across
- 3. law stating that every pure substance always contains the same elements combined in the same proportions by weight
- 5. a chemical reaction that releases heat. Opposite of exothermic reaction
- 6. a process in which one or more substances are changed into others
- 9. the reaction of an acid with a base to form salt and water
- 10. a chemical reaction accompanied by the evolution of heat
- 12. a compound usually having a sour taste and capable of neutralising alkins, and reddening of blue litmus paper.
- 14. a substance that, in aqueous solution, is slippery to the touch, tastes bitter, changes the colour of indicators, reacts with acids to form salts, and promotes certain chemical reactions.
- 15. able to be dissolved, especially in water
- 16. is either a weak acid or weak base that exhibits a colour change as the concentration of hydrogen or hydrogen ions changes in an aqueous solution
- 17. a scale ranging from 0 to 14 Ph units, reflecting the concentration of hydrogen ions in a solution
- 18. a substance that takes part in and undergoes change during a reaction products-of-a-
- 19. an atom or molecule that has acquired a charge by either gaining or losing electrons. An atom or molecule with missing electrons has a net positive charge and is called a cation one with extra electrons has a net negative charge and is called an anion
- 20. the smallest particle of an element that retains the chemical properties of the element. They are are electrically neutral, with a positively charged nucleus that binds one or more electrons in motion around it.
Down
- 1. a chemical substance formed as a result of a chemical reaction
- 2. a fundamental principle of physics. According to the law, matter can neither be destroyed nor created
- 4. a arrangement of the elements according to increasing atomic number that shows relationships between element properties
- 7. impossible to dissolve
- 8. a reaction that forms one mole of a compound from its elements in their most stable forms
- 11. a substance having the tendency to cause corrosion. Capable of destroying or eating away by chemical action
- 13. is a type of chemical reaction where a compound and an oxidant is reacted to produce heat and a new product
