Using+Chemistry


 * [[image:header.gif]]media type="custom" key="5730821" Using Chemistry**
 * Observing and recording scientific data accurately.
 * Gaining proficiency in use and application of scientific language.
 * Communicate findings and ideas to others
 * Relate knowledge to local, national and global events.


 * 1) Common Gases[[image:electricity.jpg align="right" link="Using Chemistry#Gases"]]
 * 2) Reactivity of Metals
 * 3) Corrosion of Iron
 * 4) Batteries
 * 5) Green Cars
 * 6) Assignment
 * 7) Prac Report: Electroplating

Quizes
 * Chemistry Quiz
 * Technology Quiz

Assessment
 * Classwork
 * Assignment
 * Prac Reports
 * Test

//Common Gases//
//comparison of properties of gases: Hydrogen, Helium and Carbon Dioxide//

//Reactivity of Metals//
//Develop knowledge, understanding and predictability of metal reactions. devise a// **//flow chart//** //to show how fireworks work and relate this to combustion reachtions//

//Corrosion of Iron//
//dentify and describe combustion and rusting reactions //[|Chemistry Quiz]

Electricity from chemicals
Prac: Making a battery: p 59 //Aim: Investigate the use of batteries and cells, and using this knowledge construct a battery// //This prac can also be done at home using lemons, a 2c coin and a galvanized nail.//
 * What is a lemon battery
 * Wikipedia Lemon battery



Clickview: Watch: Wet cells, Dry Cells, Fuel Cells.
Task: construct a positive/minus/interesting chart in groups to evaluate the potential uses of these technologies. [|How to use the 'Plus Minus Interesting' investigation tool]. Chart: pdf, word



Electricity production from chemicals
Batteries are made up of two separate compartments called half cells. The electrons are forced from one compartment to another. The electrons travel through the wire as they pass from one compartment to the other. As electrons leave one compartment and go to the other, charge builds up in each compartment and stops the electrons moving. A salt bridge is used to minimise the build up of charge and keep the electrons flowing..



media type="file" key="Battery.swf" align="center" width="811" height="608"

After viewing the animations answer the following questions. 1) What charge builds up in the half cell where the electrons go to? 2) What charge builds up in the half cell where the electrons come from? 3) What charged particles, from the salt bridge, flow into the half cell where the electron go to? 4) What charged particles, from the salt bridge, flow into the half cell where the electrons came from? 5) Knowing that similar charges repel each other while opposite charge attract, suggest why the flow of electrons stops as the charge builds up in each half cell.
 * Electrons are negatively charged

Investigate and note the difference between different kinds of fuel cells.
Text reference: p. 59-61
 * note the difference between an electrochemical cell and a battery
 * define: electrode, electrolyte
 * copy diagram on p 59
 * write the chemical reactions that are taking place and label these as oxidation / reduction reactions
 * copy and label a diagram of one of the four types of electrochemical cells on p 60 - 61
 * compare and contrast the characteristics of the four types of electrochemical cells on p 60 - 61
 * include the chemical reactions that occur in each type.
 * Over-to-you Q. 2-11 p. 61

__Further research__: email answers to your teacher What is the difference between a galvanic and an electrolytic cell? Who invented the first battery?

Prac - Constructing a galvanic cell
The following pair of half cells are combined to form an electrochemical cell. Fe2+(aq)/ Fe(s) and Cu2+(aq)/ Cu(s) Draw a diagram of the electrochemical cell Indicate the following - direction of electron flow in the external circuit.- direction of negative ions in the salt bridge.- the anode- the cathode - the half equations at each electrode

__Step 1__ Identify the oxidant and reductant from the electrochemical series, as shown on the right.Oxidant = FeReductant = Cu2+

__Step 2__ Write the two half reactions Cu2+(aq) + 2e- <=> Cu(s) - reduction Fe(2) <=> Fe2+(aq) + 2e- - oxidation

__Step 3__ Use the metals from each half equation as the electrodes in constructing the half cells. A salt solution containing the appropriate ions (Cu2+and Fe2+) should be used in each half cell. The direction of electron flow is from the half cell where oxidation takes place to the half cell where reduction takes place, whereas negative ions move in the opposite direction in the salt bridge.



The following pair of half cells are combined to form an electrochemical cell. Ag+(aq)/ Ag(s) and Cu2+(aq)/ Cu(s)

Draw a diagram of the electrochemical cell Indicate the following - direction of electron flow in the external circuit. anode to cathode / cathode to anode - direction of negative ions in the salt bridge. anode to cathode / cathode to anode - the anode - the cathode - the half equations at each electrode - what happens to the mass of the anode? increases / decreases / stays the same - what happens to the mass of the cathode? increases / decreases / stays the same

Solution

§ Evaluate the usefulness of different types of fuel cells as alternatives to fossil fuels how batteries work

Fuel cells have been around for many years and were widely used in the space program during the 1960's. A fuel cell used to provide electricity for the Apollo space program is shown on the right. Fuel cells varry from other types of cells in that the reactants are supplied continuously and the products continuously removed allowing for an indefinite supply of electricity. Electrodes have three distinct properties:

-the obvious one is that they must conduct elecricity; -they must be porous to allow contact between gases and electrolyte; -act as catalysts.



A fuel cell has three main parts:

- a membrane; - an anode catalyst ; - a cathode catalyst. Hydrogen is fed into the cell and flows over the anode catalyst where the molecule separates into two hydrogen ions(protons) releasing two electrons. The electrons and protons flow through the cell via separate pathways. The electrons flow through an external circuit while the protons flow through a special membrane that allows only positive ions to flow through it. On the other side, at the cathode catalyst, the oxygen molecule is separated into two oxygen atoms. As electrons arrive, the oxygen atoms increase in negative charge and react with the hydrogen ions forming water.



The nature of the electrodes is criticical for the proper function of the fuel cell as they act as catalysts and the current depends on their surface area. The reactions are : - at the anode - H2(g) => 2H+(aq) + 2e- - at the cathode O2(aq) + 4H+(aq) + 4e- => 2H2O(l) The overall reaction can be summerised as O2(aq) + 2H2(g)=> 2H2O(l)

How Green is Your Car?


> Create a labelled diagram that shows how a hybrid engine works. > In order for green cars to appeal to a wider market describe (and explain) 5 areas of research that would be necessary. >> >>
 * 1) Behind the news: hybrid cars report (watch the media file: use your headphones if you have them)
 * 2) BTN Question Sheet [[file:Hybrid Cars BTN Questions.pdf]]
 * 3) Compare the impact on the environment of a range of diesel and petrol cars (fuel efficiencies, CO2 emissions) to a new hybrid model such as the Toyota Camry. Green Vehicle Guide [[file:Green Vehicle Guide.pdf]]
 * 4) Draw up a table listing the positives and negatives of two different cars. Consider...
 * practicality,
 * need and
 * price, as well as
 * environmental performance.
 * 1) Using information from these resources, complete one of the following activities...
 * //Howstuffworks website – How hybrid cars work// //http://www.howstuffworks.com/hybrid-car.htm//
 * //A student’s guide to alternative energy sources for cars// //http://www.energyquest.ca.gov/transportation/index.html//
 * //Hybrid cars pros and cons// //http://www.physorg.com/news10031.html//
 * //Choice magazine – hybrid cars// //http://www.choice.com.au/viewArticle.aspx?id=104663&catId=100462&tid=100008&p=2&title=Hybrid+cars//
 * media type="youtube" key="evZ-C8fVrP4" height="344" width="425"
 * [[image:ToyotaHybridEnergyGraph.gif width="389" height="318"]]
 * [[image:ToyotaHybridEnergyGraph.gif width="389" height="318"]]

Other ideas about power sources:
 * [|Dr. Karl - Triple J - Why water powered engines are a myth]

[|Modern Technology]Q[|uiz]



What will be the car of the future?[[image:bmw-concept.jpg align="right" caption="BMW concept car"]]
You will create a brochure advertising the car of the future and include it in your presentation to class. (Create an electronic (PPT / MovieMaker / Photostory...) and hard copy version).

The brochure will need to be __detailed__ and... Criteria Sheet
 * be written in the persuasive language used in car broschures.
 * include information on issues with petrol/diesel powered cars,
 * recommend an alternative energy source for cars (justify choice).
 * a labelled diagram that shows how the engine / hybrid combination works (based on current research)... show detail of chemical source of power (eg. fuel cell / combustion)
 * a graph indicating performance advantages
 * a bibliography

> Some possible questions include:
 * 1) Begin with a partner discussion about what you know about alternative energy sources for cars.
 * 2) Report back to the class with what you know.
 * 3) Generate key questions to research in order to determine what alternative fuel source is best to power the car of the future.
 * What are the issues with continuing fossil fuel use?
 * What types of alternative energy sources are being developed for future cars?[[image:Peugeot-888.jpg align="right" caption="The Peugeot 888 is billed as the "personal vehicle for the future Metropolis."" link="@http://dvice.com/archives/2008/08/peugeot-888-fut.php"]]
 * What are the advantages and disadvantages of each?
 * 1) When you have a clear understanding of what the alternatives are and the advantages and disadvantages of each, then you make a decision about what the car of the future could be and can then create your brochure.

Time allowed: One week (2 class periods, plus homework) Resources: use any of the resources on this page, plus any others you can find... Nova: Car of the Future (Open Content) video resource Electric cars: Hub of the matter - article: The Economist

Electroplating
Describe the uses of electrolysis, anodising, and electroplating Compare and **contrast (Venn diagram)** the processes of Electrolysis and Electroplating
 * Practical Reports: Electrochemistry ||