Learning Intention: Students will understand the relevance of specific chemical reactions to everyday life and be able to describe the usefulness of those reactions to society.
Success criteria: Students will produce a poster, slideshow or video that investigates and describes a specific chemical reaction and it’s usefulness in our lives.
Your task is to research one of the following materials and how they can react to produce useful results – a release of heat, a new product or a portable source of energy for example. Find out how these materials are extracted or produced, the useful reaction that occurs and how this reaction benefits society. Are their any disadvantages of this reaction? (eg. greenhouse gases produced, finite resources being used or toxic by-products?
Fossil Fuels (oil, coal or gas – choose one) – combustion
Electrolysis to allow silver plating, copper plating etc
Learning Intention: Students will understand the meaning of exothermic and endothermic reactions.
Success Criteria: Students will be able to identify exothermic and endothermic reactions and give examples of each. They will be able to explain why these processes to considered to be exothermic or endothermic.
Endothermic reactions absorb energy, causing a decrease in temperature (eg. photosynthesis, melting and evaporation all require energy to be added to the system). Exothermic reactions release energy, causing an increase in temperature (Combustion, freezing, and condensation release energy from the system).
Mr Kent’s Chemistry page has some excellent examples of exothermic and endothermic processes and chemical reactions. We will be conducting four experiments in class and measuring the temperature change to determine which are endothermic and which are exothermic reactions. Leave comment below about what you found from your experiments. Can you think of any examples of exothermic and endothermic processes from home?
Thanks to Duncan Patti for producing the slideshow above, which is a good summary of what you should know about chemical reactions from Year 7 and 8 science and an introduction to Year 9 Chemistry. You need to know the difference between a physical change and a chemical reaction (what evidence is there for a chemical reaction?). You also need to know the four ways in which you can increase the rate of a reaction. It is also very helpful if you can remember the chemical formula for the first twenty elements, as well as some other common ones (iron, copper, silver and lead).
So far this term we have done lots of experiments to demonstrate the properties of different materials, such as:
“Making Rayon – a regenerated fibre”;
“Making a Colloid – sulfur and methylated spirits in water”
“Making a Gel” and
“Cold cream – an emulsion”.
Well done Sarah and Emma for making their own homemade cosmetics – an exfoliating gel with poppy seeds and a shampoo from an emulsion of honey and egg yolk. The image above is from Quizlet, where you can create your own flashcards, scatter games and other activities to assist you to remember the improtant terms and definitions for this unit of work.
Materials scientists are constantly working on innovations to improve the manufacture and use of fabrics, structural materials and packaging. This article, from Web Urbanist, describe “8 Substances that will shape the future“.
While I am on Year 7 camp at Roses Gap (19th to 21st March) those Year 9 students not on the Advance camp should be studying for their science test. This test will be on Friday 23rd March and include all the work we have done this term. You should read your text book chapter and write some study notes as well as review your workbook with the practical experiments we have completed.