S4 Chemistry The Mole REVISION Formulae tell you how many of each atom are in a molecule. Different atoms have different masses. Level 4 NEW LEARNING Formulae and balanced equations Formula Mass and the mole Concentration and solutions National 5

Starter Questions Which of the following contains molecules? Calcium chloride or carbon hydride? Carbon hydride. What type of bonding is present in sulfur dioxide, a gas at room temperature? Covalent 3. Why don’t ionic solids conduct? The ions are not free to move and carry charge. S3 Revision

Lesson 1: Simple Formulae Today we will learn to Use compound names and formulae to identify the elements they contain and vice versa. We will do this by Revising the rules we learned in S2/3 and playing some naming games. We will have succeeded if We can name a compound from it’s elements or formula.

Naming Compounds If a compound contains just two elements the compound name consists of the names of both elements but the last part of the second name becomes –ide. e.g. magnesium and oxygen make magnesium oxide. carbon and chlorine make carbon chloride. If a compound contains more than two elements and one of them is oxygen the compound name consists of the names of both the other elements but the last part of the second name becomes –ate or –ite depending on the number of oxygen atoms. e.g. copper, sulfur and oxygen make copper sulfate. sodium, phosphorus and oxygen make sodium phosphate.

Naming Compounds Activity 4.1 Naming Compounds Game Your teacher may let you play this simple card game to practice naming simple two and three element compounds. NOTE Fill in the blanks in the following table:

Covalent Formulae Symbols can be used to represent atoms of the different elements. A chemical formula is used to represent the type and number of each element in a compound. E.g. water (hydrogen oxide) has the chemical formula H2O this means that in every water molecule there are 2 hydrogen atoms bonded to 1 oxygen atom.

Covalent Formulae After discussion with your teacher and others make sure you know how to work out the number of atoms of each element in a compound from its chemical formula. NOTE Complete the following table:

Valency and Group Number You will remember from the previous topic on bonding that atoms join together in order to form a complete outer shell. In covalent bonding they do this by sharing their unpaired outer (valence) electrons. DISCUSS After discussion with your teacher and others make sure you know how to work out the valency of elements. NOTE Complete the following table:

Exit Task Mr Wrong Explain why this student statement is wrong… “Oxygen atoms have six outer elctrons so will have a valency of 6” Pupils could answer this, and if time, do some examples using the show me boards.

Starter Questions Draw molecules of the follwing compounds to show their shape: 1. Ammonia (NH3) 2. Carbon chloride (CCl4) 3. Water (H2O) 4. Phosphorus Trihydride (PH3) S3 Revision

Lesson 2: Writing Formulae Today we will learn to Use valencies and words to write simple chemical formulae. We will do this by Following the pattern of some worked examples learning about prefixes and using cards to work out bonding pairs. We will have succeeded if We can write some simple chemical formulae for new compounds.

Writing Formulae If we look at an example of two non-metal elements, oxygen and hydrogen, joining together to form water: You can see that oxygen has two unpaired outer electrons, a valency of 2 and hydrogen just one unpaired electron, a valency of 1. The oxygen therefore needs two hydrogen atoms to fill its outer electron clouds. A ratio of 1:2 oxygen to hydrogen atoms, in other words the valency number of one element tells you the number of atoms of the other element you need. This is called crossing over the valencies.

Writing Formulae

Writing Formulae

Writing Formulae

Writing Formulae Exceptions Unfortunately in chemistry there are lots of substances that don’t have chemical formulae that can be worked out using the above method, sometimes two elements can combine in two or more different ways. However these exceptions are given names that allow us to simply work out the formula from the name. Prefixes such as mon, di, tri, tetra, etc. are used to give the number of atoms of each element in the compound. Carbon can combine with oxygen in two ways forming compounds with the chemical formula CO and CO2. In order to tell them apart they are given the following names: CO = carbon monoxide CO2 = carbon dioxide Here the prefixes tell you the number of oxygen atoms in the chemical formula. Another set of similar compounds are sulfur dioxide SO2 and sulfur trioxide SO3.

Writing Formulae

Consolidation Task Activity 4.2 Covalent Bonding Pairs Game Your teacher may let you play this simple card game to practice working out chemical formulae of covalent compounds.

Starter Task Complete Quick Test 1 in your booklet and we will review as a class. You have 15 minutes! S3 Revision

Quick Test 1 - Answers S3 Revision

Quick Test 1 - Answers Work out the chemical formulae of the following compounds . a. PCl3 b. NI3 c. SBr2 d.  HF e. SiC f. GeH4 g. H2O h. SiF4 UF6 j. PCl5 C 4. B S3 Revision

Lesson 3: Ionic Formulae Today Nat 5 pupils will learn to Write ionic formulae for chemicals to show the charges/ions present. Nat 4 pupils will practice more simple formulae. We will do this by Drawing simple formulae and adding charges or using Roman numerals from compound names. We will have succeeded if We can write formulae from a wide range of given information and select the correct type.

Ionic Formulae

Ionic Formulae

Ionic Formulae

Objective Traffic Lights How do you feel about the lesson objectives? Red = don’t think I have grasped this Amber = feeling OK about this, have just about got there Green = Confident I have achieved this If there are no coloured cards available (e.g. in planners), Mark corners in the room for each colour and ask pupils to move to indicate confidence.

Starter Task Activity 4.3 Ionic Bonding Pairs Game Your teacher may let you play this simple card game to practice working out chemical formulae of ionic compounds. S3 Revision

Lesson 4: More Ionic Formulae In this lesson we will learn to… Write ionic formulae from compound names with group ions or Roman Numerals in them. We will do this by… Working through some worked examples and trying some on our own. Lesson 4 (cont) We will have been successful if… We can write ionic formulae from avariety of different types of compound name.

More Ionic Formulae Exceptions Unfortunately in chemistry there are lots of substances that don’t have chemical formulae that can be worked out using the simple method, this is because transition metals can have more than one valency and have a group all of their own with no group number. In order to let you know what the valency of the transition metal is chemists use roman numerals in the chemical name. NOTES Complete the following table:

More Ionic Formulae

More Ionic Formulae

More Ionic Formulae Ionic compounds containing more than two atoms Some ionic compounds contain more than two elements, their chemical names tend to end in –ate or –ite as we have already seen, but there are a few others. On p 8 of your data booklet you will see a table containing all the ones you will need to know. Ions containing more than two elements are known as group ions. NOTES Use page 8 of your data booklet to complete the following table:

More Ionic Formulae

More Ionic Formulae

More Ionic Formulae

Pyramid Exit Task Question you have about the lesson Things you have been reminded of today Things you have learned today

Starter Task Complete Quick Test 2 in your booklet and we will review as a class. You have 5 minutes! Circle the correct answers. S3 Revision

Answers Quick Test 2 1. D, 2. B, 3. B, 4. B, 5. B, 6. D Ask 3, Then Me! Mark your answers and check with neighbours to see why you got any wrong. S3 Revision

Lesson 5: Chemical Equations Today we will learn to Write chemical equations to represent reactions. We will do this by Writing word equations from sentences and converting them to symbols and formulae We will have succeeded if We can correctly represent reactions using equations.

Chemical Equations Word Equations During a chemical reaction reactants are turned into new substances called products. This can be shown by a word equation where the chemicals reacting are shown on the left hand side and the products formed on the right. For example, in the reaction between magnesium ribbon and oxygen gas, a white powder magnesium oxide is produced. The word equation for this is: magnesium + oxygen à magnesium oxide Notice that only the chemical names are used in the equation and not descriptions. DISCUSS After discussion with your teacher and others make sure you know how to work out a word equation from a description of a chemical reaction.

Chemical Equations Work out the word equations from the following descriptions of chemical reactions: Sodium metal reacts violently with water producing hydrogen gas and a solution of sodium hydroxide. 2. Carbon dioxide gas and black copper oxide powder are formed when green copper carbonate powder is heated in a test tube. 3. When iron is produced in a blast furnace from iron ore, the iron(III) oxide in the ore reacts with carbon monoxide gas. Carbon dioxide is also formed in the reaction.

Chemical Equations

Chemical Equations

Balanced Chemical Equations Activity 4.4 Balanced Chemical Reactions Try making a molecule each of hydrogen H2 and oxygen O2. Use them to make a molecule of water H2O. The chemical equation for this reaction should be: H2 + O2 à H2O But you should find that you have an atom of oxygen left over. In reality this cannot happen as we cannot create or destroy matter, so in order to use up this extra oxygen atom we need to react it with another hydrogen molecule.

Balanced Chemical Equations

Balanced Chemical Equations Activity 4.5 Balanced Chemical Equation Activity Your teacher may let you play this activity which should help you to understand how to balance chemical equations.

Tell me three things... you have done well you would like to find out more about you know now that you didn’t know 50 minutes ago

Starter Questions What type of bonding leads to the formation of molecules? Covalent. What is the charge on a phosphorus ion? 3 positive : P3+ 3. Describe (or draw) an ionic lattice. S3 Revision

Lesson 6: Balancing Equations Today we will learn to Use a ‘long’ way to help us balance equations. We will do this by Watching some examples of the accounting method and copying the technique. We will have succeeded if We can balance equations using this or our own method. .

Balancing Equations

Balancing Equations

Balancing Equations

ConsolidationTask Complete Quick Test 3 in your booklet and we will review as a class. You have 15 minutes! S3 Revision

Answers Quick Test 3 1 a. lithium + water  lithium hydroxide + hydrogen b. copper carbonate  carbon dioxide + copper oxide c. hydrogen peroxide  water + oxygen   2 a. Cu + S  CuS b. Mg + ZnSO4  MgSO4 + Zn c. 2SO2 + O2  2SO3 Ask 3, Then Me! Mark your answers and check with neighbours to see why you got any wrong. S3 Revision

Definition Choose three new words you have learnt in this topic and write dictionary definitions.

Starter Questions Explain why it is necessary to balance a chemical equation after it has been written using formulae. Atoms cannot be created or destroyed in a chemical reaction, so must appear on both sides of the equation. 2. How many molecules of hydrogen react with one molecule of oxygen when water is made? 2 S3 Revision

Lesson 8: The Mole Today we will learn to Compare the number of atoms present using the mole. We will do this by Learning what a ‘mole’ represents and using it in calculations. We will have succeeded if We can describe to another pupils what the mole means.

The Mole We have just seen with balanced chemical equations that it is important that we have the right number of molecules reacting, but molecules are unimaginably small and it is impossible to see them to count, so how do chemists measure quantities of chemicals? If we just compare masses we could have two things weighing the same. For example, 1kg of cricket balls and 1kg of ping pong balls. However would we have the same number of balls? The answer is obviously no, there would need to be many more ping pong balls as they are so light. Chemicals are the same they all weigh different amounts, some molecules are very light others much heavier in comparison. We need a way that we can compare the number of molecules rather than the mass.

The Mole

The Mole A dozen is just a fixed number, 12, and so if we know the mass of one dozen we can use simple calculations to find the mass of other amounts of the object. In chemistry we use a fixed amount called a mole, like a dozen it is a fixed number it just happens to be very large 602,000,000,000,000,000,000,000! This is because atoms and molecules are so small we need a colossal number of them to be able to weigh them. The good news is that we don’t need to know how many atoms or molecules are in a mole we just need to know how much one mole of a particular substance weighs. Just like you did with the small objects you weighed earlier.

The Mole

The Mole

Mass by Proportion 1 mole of H2O = 18g Like all chemical proportions, mass can be calculated by cross multiplication : 1 mole of H2O = 18g so 2 moles of H2O = (2 x 18) ÷ 1 = 36g 1 mole of H2O = 18g so 0.12 moles of H2O = (0.12 x 18) ÷ 1 = 2.16g 1 mole of Mg(NO3)2 = 148g so 0.1 moles of Mg(NO3)2 = (0.1 x 148) ÷ 1 = 1.48g 1 mole of Mg(NO3)2 = 148g so 6.5 moles of Mg(NO3)2 = (6.5 x 148) ÷ 1 = 962g

The Mole

The Mole

The Mole

Explain what you have learnt today and how you have learnt it What? How? Explain what you have learnt today and how you have learnt it ?

Starter Questions

Starter Questions

Starter Questions

Lesson 9: Solutions Today we will learn to Calculate the concentration of a solution We will do this by Learning what concentration is measured in and doing some calculations We will have succeeded if We can make up a solution of a given concentration by working out the mass needed to make one.

Solutions Solutions When you make up an aqueous solution you are dissolving a solid (solute) in water (solvent). The more solid you dissolve the more concentrated the solution. Alternatively we could dissolve the same mass of solid but reduce the volume of water used which would also make the solution more concentrated. So concentration depends on the mass of solid dissolved and the volume of water used. We have already seen that we cannot compare masses in chemistry but can compare number of moles. In chemistry we also use the litre as a standard measurement of volume of liquid. This leads to the following formula: Concentration = number of moles of solid Volume of water in litres

Solutions

Concentration by Proportion Like all chemical proportions, concentration can be calculated by cross multiplication : 2 mole of NaCl in 0.5 litre – what is the concentration? You need to know the number of moles in 1 litre. (mol l-1) 0.5 litres contains 2 moles So 1 litre must contain (2x1) ÷ 0.5 = 4 mol l-1 You have a 5 mol l-1 solution – what volume would contain 0.75 moles? 5 moles are contained in 1 litre So 0.75 moles would be in (2x0.75) ÷ 5 = 0.3litres (300cm3)

Solutions Activity 4.7 Making Solutions Make up the following solutions as accurately as possible. Your teacher may show you how to use more accurate glassware: .Dissolve 5.85g of sodium chloride in 100cm3 of water. .Dissolve 7.2g of sodium chloride in 250cm3 of water. Work out their concentrations. Hint – how many moles of sodium chloride are present in each sample? Work this out first!

ConsolidationTask Complete Quick Test 4 in your booklet and we will review as a class. You have 15 minutes! S3 Revision

Answers Quick Test 4 1a. 0.5 b. 0.1 c. 4 2a. 5g b. 4g c. 444g Ask 3, Then Me! Mark your answers and check with neighbours to see why you got any wrong. S3 Revision

Definition Choose three new words you have learnt in this topic and write dictionary definitions.

Starter - Definition Match Match the word to the definition Mole A mixture produced by dissolving a solute in a solvent like water. Gram Formula Mass A given number of atoms or molecules of any substance. Solution A mole given in grams.

Lesson 10: Calculations from Equations Today we will learn to Use balanced equations to predict quantities produced or used up in chemistry. We will do this by Learning a step by step technique and applying it. We will have succeeded if We can predict how much product is made from an equation and a starting quantity

Calculations

Calculations Step by Step: Find or write the balanced chemical equation. Write the mole ratio for the important items in the question. Convert the moles into grams (you need to work out GFM at the side for this) Cross multiply to find the mass produced from 1 g 5. Cross multiply again to find the mass produced from the given mass.

Calculations

Calculations

Calculations

Exit Task Flow-Chart Draw a flow-chart showing the lesson

Taboo Describe the following key words without using that word (it is taboo!). Mole Concentration Solution

Lesson 11: Making a Profit

Making a Profit Today we will learn to Use what you have learned about the chemical industry and reactions to work out the profitability of a process. We will do this by Investigating a possible way to make quick money! We will have succeeded if

Making a Profit a. Below is the chemical equation for the reaction, can you balance it. CH3CO2H(g) + C(s) ® CO2(g) + C8H16(l) What mass of petrol (C8H16(l)) will be produced if 240kg of ethanoic acid reacts with 48kg of carbon? 112Kg

Making a Profit c. If Vinegar costs £1.00 per kg, coal costs £2.00 per kg and running the plant costs £1 per kg of petrol produced; what is the minimum price the company must sell their petrol at per kg to make a profit. £4

Making a Profit d. If 1 litre of petrol weighs roughly 700g can the business make a profit with today’s petrol prices? e. Would you invest in the company?