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Chemistry recipes

Chemistry recipes. Chemical Equations. EL: To understand the law of conservation of mass the different types of , how to write chemical equations and how to identify the 5 main types of reactions . Focus: Conservation of mass, writing equations and chemical reactions.

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Chemistry recipes

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  1. Chemistry recipes Chemical Equations EL: To understand the law of conservation of mass the different types of , how to write chemical equations and how to identify the 5 main types of reactions. Focus: Conservation of mass, writing equations and chemical reactions

  2. "The Law Of Conservation Of Mass" The mass of substances produced (products) by a chemical reaction is always equal to the mass of the reacting substances (reactants). Let’s test this law! In groups (3-4 people) carry out the investigation wearing your personal protective equipmentusing the method provided Record your results and share your findings by writing them on the board. Answer the questions on the sheet as well as “How do the result of other groups compare to yours? Explain”

  3. Chemical equation = chemical recipe • Hydrogen peroxide breaks down to form oxygen gas and water. The word equation for this reaction is shown below: Hydrogen peroxide ==> oxygen gas + water • the reactant - hydrogen peroxide - is on the left of the arrow • the products - oxygen gas and water - are on the right.

  4. Chemical equation = chemical recipe Methane burns to form carbon dioxide and water. The word equation for this reaction is shown below. Methane + oxygen ==> carbon dioxide + water. Note that when a substance burns, it is actually reacting with oxygen. So oxygen must appear on the left side of the equation as a reactant even though it is not stated in the description above.

  5. Write the word equations for the following chemical reactions. a) Magnesium burns in oxygen to form a white powder known as magnesium oxide. b) Hydrogen and oxygen gases react to form water. c) Sugar reacts with oxygen in our body to produce carbon dioxide and water. d) Zinc metal and hydrochloric acid react together to produce hydrogen gas and zinc chloride. * Complete “writing worded equations” worksheet

  6. Scientists describe a chemical reaction by writing a chemical equation using symbols to represent the atoms taking part. • The symbols that are used to represent the substances are called Chemical formula. • There are two types of Chemical formula Molecular Formulas or Ionic Formulas

  7. Writing the Chemical equation for the production of water

  8. Extension - Writing Ionic formulas • When writing the formula of an ionic compound a few steps must be followed.Step 1 - Write the formula of each ion and its charge.Step 2 - Balance the positive and the negative charges.Step 3 - Use subscripts to write the formula.Step 4 - Use brackets if the ion has more than one capital letter and more than one ion is required. • Example 1 What is the formula of aluminium sulfate.Step 1 - Al+3 and SO4-2Step 2 - Balance the positive and negative charges.In order to balance 3+ and 2- we have to find the lowest common multiple.In this case it is 6.In order to get 6+ we need 2 Aluminium ions.In order to get 6- we need 3 sulfate ions.Step 3 and 4 Write the formula using subscript.Al2(SO4)3Note how we used brackets around the sulfate ion. That's because sulfate is an ion with two capital letters and we need more than one sulfate ion.

  9. Extension – Writing chemical Ionic formulas • http://www.dynamicscience.com.au/tester/solutions/chemistry/ionicformexeactivity.html

  10. 5 Main chemical recipes • Watch the following clip from You tube types of chemical reactions to learn more about 4 of the 5 main types of chemical reactions • Synthesis • Decomposition • Single replacement • Double replacement reactions. • You will be performing these reactions in coming lessons

  11. And the last and most important Combustion reactions • Combustion reactions are those in which the substance reacts with oxygen and heat is released . • Common combustion reactions • Burning of gas in stoves • the fuel(octane) burnt to provide energy to a car • Respiration Watch this demo • methane bubbles combustion reaction

  12. Reflection • Update your concept map with what you learnt about chemical reactions today • In your workbook write down what do you enjoy in todays lesson or found interesting?

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