Chemical reactions

3. law stating that every pure substance always contains the same elements combined in the same proportions by mass
4. a process in which one or more substances are changed into others
5. 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
7. 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.
11. a substance having the tendency to cause corrosion. Capable of destroying or eating away by chemical action
12. 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.
14. a substance that takes part in and undergoes change during a reaction products-of-a-
15. a arrangement of the elements according to increasing atomic number that shows relationships between element properties
16. impossible to dissolve
18. is a type of chemical reaction where a compound and an oxidant is reacted to produce heat and a new product
19. a chemical reaction accompanied by the evolution of heat
20. able to be dissolved, especially in water

1. a reaction that forms one mole of a compound from its elements in their most stable forms
2. the reaction of an acid with a base to form salt and water
6. a fundamental principle of physics. According to the law, matter can neither be destroyed nor created
8. a scale ranging from 0 to 14 Ph units, reflecting the concentration of hydrogen ions in a solution
9. a chemical substance formed as a result of a chemical reaction
10. 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
13. a chemical reaction that releases heat. Opposite of exothermic reaction
17. a compound usually having a sour taste and capable of neutralising alkins, and reddening of blue litmus paper.