Going Through Worksheets

In today's Science lesson, we went through worksheets which we had completed in the last few days. The worksheets were on equations of acids and alkalis and chapter 14 workbook, Changing Matter.

3 Thoughts:
1) The meaning of decomposition is known as breakdown and not combine. Examples of substances which undergo decomposition in the presence of heat are calcium carbonate, copper carbonate and sugar.
2) I learnt that producing light in a light bulb is a physical change as the filament in the light bulb is heated up, and electrical energy is converted to heat and light energy. In addition, the change is reversible and no new substances are formed.
3) In the reaction of acids and metal carbonates or reactive metals, chemical salts are always formed. We name the salts based on the types of acids and metals used at the start of the experiment. For example, when sodium and hydrochloric acid is being mixed together, the salt formed is called sodium (follows the name of the reactive metal used) chloride (known as the last name which is based on the type of acid used).

2 Questions:
1) Does decomposition occurs at a specific temperature?
2) The changing of energy from one form to another is not a chemical change right?

1 Useful application:
1) By knowing the names of the salts produce through chemical reactions, we are able to know which substances are given out in the different types of reactions.

(Few examples of the equations on the reactions of acids and reactive metals)

Sources: Google Images