1 / 12

Revision of Topic 1- Chemical Reactions

Revision of Topic 1- Chemical Reactions. 1.Identify a chemical reaction by a change in the appearance of a substance:- - a colour change - bubbles forming – a gas being given off - a solid (precipitate) being formed. 2. Identify a chemical reaction by a detectable energy change could be:-

michaelholmes
Télécharger la présentation

Revision of Topic 1- Chemical Reactions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Revision of Topic 1- Chemical Reactions • 1.Identify a chemical reaction by a change in the appearance of a substance:- • - a colour change • - bubbles forming – a gas being given off • - a solid (precipitate) being formed

  2. 2. Identify a chemical reaction by a detectable energy change could be:- • HEAT being given off – EXOTHERMIC • Heat being taken in – ENDOTHERMIC • Sound being produced • Light being produced

  3. 3. State that all chemical reactions involve the formation of one or more new substances. • Chemical reactions are hard to reverse back to starting materials e.g. table salt is made from chlorine a gas and sodium a metal.

  4. 4. Give examples of chemical reactions which occur in our day to day lives. • E.g. 1) eggs frying • 2) wood burning • 3) a firework taking off • 4) cake baking

  5. 5. State that everything is in the world is made from about 100 elements. • Elements are listed in periodic table • They are the simplest substances possible. (Cannot be broken down to anything simpler)

  6. 6. State that each element has a name and a symbol. • Symbols can be just one letter e.g. H for hydrogen. • Symbols can be two letters e.g. Br for Bromine (One uppercase and one lowercase letter).

  7. 7. State that compounds are formed when elements react together. • When 2 or more elements chemically join together we get a compound. • E.g. sodium + chlorine  sodium chloride • Magnesium + iodine  magnesium iodide

  8. 8. State that mixtures occur when two or more substances come together without reacting. • No chemical reaction involved as substances are easy to reverse – can get starting material back again e.g. salt and sand.

  9. 9. State that a solution is formed when a solute dissolves in a solvent. • Solvent – the liquid in which the solute is dissolved e.g. water • Solute – the substances being dissolved e.g. sugar

  10. There are different types of solutions:- • Dilute solutions where there is little solute in the solution compared to the amount of solvent. • Concentrated solutions where there is a lot of solute dissolved in the solvent compared the amount of solvent. • Saturated – where no more solute can be dissolved.

  11. 10. The compounds with the name ending in –ide contain the two elements indicated • e.g. • (I) sodium + sulphur  sodium sulphide • (II) copper + oxygen  copper oxide

  12. Compounds ending –ite or –ate indicates the additional element oxygen. • Compound ending in -ite have fewer oxygens than compounds ending in -ate. • E.g. • Calcium + sulphur + oxygen --> calcium sulphite • Calcium + sulphur + oxygen --> calcium sulphate • In the above example the formula for lead sulphite is CaSO3 • the formula for lead sulphate is CaSO4

More Related