Year 9 Science: Chemical Reactions

Chemical Reactions Notes

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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).

It’s a Material World!

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.

Welcome Back – Year 9 Science 2012!

Welcome back to school for another fabulous year of science and learning! Please bookmark this site for future reference as this will be the starting point for all our science studies during the year. Our first unit of work will build on your knowledge of matter, atoms and molecules, elements and compounds and chemical reactions.

Learning Intention:

(1) Students will understand that all matter is made of atoms which are composed of protons, neutrons and electrons; natural radioactivity arises from the decay of nuclei in atoms.

(2) They will know that chemical reactions involve rearranging atoms to form new substances; during a chemical reaction, mass is not created or destroyed.

(3) Students will understand chemical reactions, including combustion and the reactions of acids, are important in both non-living and living systems and involve energy transfer.

Chromotography with Smarties and Autumn leaves

smarties#2

Chromotography  is a collective term for a set of laboratory techniques used to separate mixtures. It includes paper chromotography, thin-layer chromotography and gas chromotography. Paper chromotography is used for separating mixtures such as inks and dyes. In our practical experiment, we will use the natural food  dyes used to colour “Smarties”, although the artificial colouring used for “M and M’s” work well too. This is also a great time of year to investigate the pigments in autumn leaves – as chlorophyll breaks down to produce xanthophyll, carotene and anthocyanin. Another experimental method for leaf chromotography here.

Why do some trees have leaves that change colour in the autumn? How is chromotography used by forensic scientists and in industry? Please do some research and post your answers in the comments section below.

Investigating Elements

 

Atom and hands machine drawingphoto © 2010 Bascom Oswald Hogue | more info (via: Wylio)

 

 

 

 

 

 

 

The drawing above is from Wylio,  a great place to search for free-to-use images for your blogs and wikis. It shows a diagram of the model of an atom, with a central nucleus and the path of three electrons around the outside. Elements are pure substances consisting of just one type of atom. Compounds are made up of molecules that consist of more than one type of atom. All the known elements are arranged in the periodic table in order of their atomic number.

elements_appDuring today’s lesson we will be looking at a range of different elements and describing them. You will use the Google doc, “Investigating Elements” to record your results. Click on the link and download the document onto your computer. There are 14 different elements to observe and complete each column – name, symbol, atomic number, description and what you might find that element in. We will also have some time this week to use the iPads to investigate “The Elements” app, which has amazing interactive images of each of the pure elements and extensive information about each element. This app can be purchased through the iTunes store for $13.99.