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Oxidation, Reduction & Combustion. http:// www.zeeco.com/rentals/rentals.php. Today’s Lesson. Some more info on Combustion, Displacement, Oxidation and Reduction Small Activity (will take until next week) Second period - essay. Different Types of Reactions.
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Oxidation, Reduction & Combustion http://www.zeeco.com/rentals/rentals.php
Today’s Lesson • Some more info on Combustion, Displacement, Oxidation and Reduction • Small Activity (will take until next week) • Second period - essay
Different Types of Reactions • Exothermic Reactions – These types of reactions release energy. Energy might be released in the form of heat, light or sound. They often give off heat and may feel hot. • Endothermic Reactions – These type of reactions require energy. Energy may be absorbed in the form of heat, light or sound. They normally absorb heat and may feel cold.
Combustion Reactions • Combustion reactions need oxygen to occur. They often have water as one of the products. • Remember reactants are on the left of an equation, the products are on the right of an equation. • They are normally exothermic and release energy in the form of heat, light and sound. • 2 C8H18 + 25 O2 18 CO2 + 18 H2O
Stating States • When we write equations, we normally state which type of state (solid, liquid, gas) it is. They are stated below: • (l) = liquid • (g) = gas • (s) = solid • (aq) = aqueous (in solution or dissolved)
Oxidation Reactions • Oxidation occurs when a substance reacts with oxygen. An oxygen atom is gained in the molecule or compound in question • 2Mg (s) + O2 (g) 2 MgO (s) • Note how the Magnesium now has one more oxygen atom on the right hand side. • The Magnesium has now been oxidized
http://scienceprojectideasforkids.com/2010/oxidation-sparklers/http://scienceprojectideasforkids.com/2010/oxidation-sparklers/
Reduction • A reduction reaction occurs when a compound or molecule loses oxygen. • CO2 (g) + C (s) 2CO (g) • In this reaction, note how the Carbon Dioxide loses one oxygen to become Carbon Monoxide. • CO can be used to kill someone quite easily as your lungs thinks it’s oxygen and you choke to death
Displacement • When two metals can react, the metal that is most reactive will react first. • This quite often happens with Zinc bolts on ships. Zinc is more reactive than Iron, so the Zinc with oxidize first before the Iron. • Iron Oxide + Carbon Iron + Carbon Dioxide • They are also often used in find halides (Group 7) in solutions as they will be displaced in Silver Nitrate. • We will learn a bit more on this next lesson
http://www.frankswebspace.org.uk/ScienceAndMaths/chemistry/reactivitySeries.htmhttp://www.frankswebspace.org.uk/ScienceAndMaths/chemistry/reactivitySeries.htm
Questions • Name two exothermic and one endothermic reaction that occurs around us • What is needed for a combustion reaction to occur and what is it’s normal byproduct? • How are reduction and oxidation reactions different? Can reduction and oxidation occur in the same reaction?
Small Experiment • You need: 2 test tubes, 2 nails, some Magnesium and HCl • Put one nail in the test tube. • Wrap magnesium coil around the second nail and place it in the test tube. • Now, write down what you think will happen when we put Hydrochloric Acid into each test tube.
Continued • Fill the test tubes with HCl until it is just above the level of the nail • Have a quick look at both test tubes and look at it later in the lesson • Before the end of the lesson, briefly write down what is occurring in both test tubes. We will look at them later in the lesson. • We will also complete our essay.
