Chemistry Past Paper Notes (PDF)

Task: Complete the worksheet from last lesson about reacting metals with acids Finished? Describe how to test for the presence of hydrogen in a reaction. Acids and Carbonates Wednesday 22 January 2025 Bronze: State that acids react Aim: Know that carbon dioxide is with carbonates....

Task: Complete the worksheet from last lesson about reacting metals with acids Finished? Describe how to test for the presence of hydrogen in a reaction. Acids and Carbonates Wednesday 22 January 2025 Bronze: State that acids react Aim: Know that carbon dioxide is with carbonates. produced when acids react with metal carbonates. I can describe the test for carbon dioxide. Silver: Describe how excess insoluble solid can be used to Keywords: provide a completed reaction. Carbonate Equation Gold: Explain that reactions Reactant that produce heat are Product exothermic. Salt Exothermic To know how carbonates react with acids. Add metal carbonate to acid and collect the gas that comes off. Test the gas. Write what you observe. Metal Carbonates Using what you know about naming compounds, what is in a metal carbonate? For example: Copper carbonate  Metal carbonates are also chemicals that will neutralise acids. with acid Carbonates are chemicals that contain carbon and oxygen. Metal carbonates are also chemicals that will neutralise acids 7F Reactions with acid - Reaction of carbonates with acid To know how carbonates react with acids. Calcium carbonate reacts with acid to produce a gas which turns the limewater cloudy. What is the name of this gas? The other products of this reaction are a salt and water. Complete the word equation for the reaction of a carbonate with acid: carbonate + aci ? +? + ? d To know how carbonates react with acids. Complete word equations for these reactions: a. copper carbonate and sulphuric acid b. magnesium carbonate and sulphuric acid c. calcium carbonate and hydrochloric acid d. magnesium carbonate and hydrochloric acid e. copper carbonate and nitric acid We are going to watch the reaction of calcium carbonate and hydrochloric acid. https://www.youtube.com/watch?v=pCDAXJyrABw What are the reactants of this reaction? What are the products? Write the word equation for this reaction? One of the products was a gas. How did they test for the presence of this gas? Do you know another way to test for the presence of carbon dioxide?  Task: Complete the word equations on the worksheet. Use the table below to help you name the salts. Name of acid Type of salt produced Hydrochloric acid …. chloride Nitric acid … nitrate Sulphuric acid … sulphate Ethanoic acid … ethanoate Finished? Write the word equations out as symbol equations. Neutralisation Wednesday 22 January 2025 Bronze: State that acids react Aim: Know what happens when with bases. acids react with alkalis. I can put these formulae into symbol Silver: Know that the opposite of equations. I can name some salts an acid is a base, that alkalis are and describe a use for them. soluble bases and that acidity is Keywords: measured on the pH scale. Neutralisation Gold: Construct a general pH scale equation for neutralisation Acid Alkali The pH scale was invented to measure how acidic something is. Universal indicator changes color depending on how acidic or alkali something is. By comparing the color to the colours on the chart you can asign a numerical value to the acidity or alkalinity of a substance.  What happens if you mix an acid with an alkali? If the acid and alkali were of equal strength (they were both strong or weak acids and alkalis) then the solution would become neutral. What is the pH of a neutral solution? The pH of a neutral solution is pH7. An example is pure water.  The reaction between an acid and an alkali is called neutralization. The general equation: Acid + Alkali  Salt + Water Examples of acids? Examples of alkalis? Hydrochloric acid Potassium hydroxide Sulfuric acid Magnesium hydroxide Nitric acid Barium hydroxide  The reaction between an acid and an alkali is called neutralization. The general equation: How do we know the Acid + Alkali name  Salt of the + Water salt? Hydrochloric acid + magnesium hydroxide   The reaction between an acid and an alkali is called neutralization. The general equation: How do we know the Acid + Alkali name  Salt of the + Water salt? Hydrochloric acid + magnesium hydroxide   The reaction between an acid and an alkali is called neutralization. The general equation: How do we know the Acid + Alkali name  Salt of the + Water salt? rochloric acid + magnesium hydroxide  magnesium chloride + wate  Acid + Alkali  Salt +Hydrochloric Water acid = Potassium HCl hydroxide = KOH Nitric acid = HNO₃ Magnesium hydroxide = ? Sulfuric acid = H₂SO₄ Hydrochloric acid + potassium hydroxide  Hydrochloric acid + magnesium hydroxide  __________ + ____________  barium nitrate + water __________ + ____________  magnesium sulfate + water Neutralisation equation practice worksheet Write these as symbol The pH scale was invented to measure how acidic something is. Universal indicator changes color depending on how acidic or alkali something is. By comparing the color to the colours on the chart you can asign a numerical value to the acidity or alkalinity of a substance. Acidity is measured on a pH scale This ranges from 1 to 14. 1 being the most acidic and 14 being the most basic. Universal indicator can be used to test for an acid or a base. Acids show as red and bases as purple. Soluble – able to dissolve What is a base? A beaker of Hydrochloric acid is below. Sodium hydroxide was added to the acid slowly 1 cm3 at a time Universal indicator has been added to the hydrochloric 1.Why is the beaker of acid coloured red? 2.What is the formula for Hydrochloric acid? 3. At what point was the hydrochloric acid neutralised? 4. How would the results have been different if a weaker alkali was used? 1.Why is the beaker of acid coloured red?  it has indicator in it  the acid is red 2. What is the formula for Hydrochloric acid?  HCA  NaOH  HCl H2SO4 3. At what point was the hydrochloric acid neutralised? 4. How would the results have been different if a weaker alkali was used?  greater volume of alkali needed  pH would change much quicker 1.Why is the beaker of acid coloured  red?  it has indicator in it  the acid is red 2. What is the formula  for Hydrochloric acid?  HCA When NaOH 7cm3 of NaOH  HCl and was added Hit2SO reached 4 pH7 3. At what point was the hydrochloric acid neutralised? 4.  How would the results have been different if a weaker alkali was used?  greater volume of alkali needed  pH would change much quicker Neutralisation: Means to cancel out A chemical reaction happens when an acid and alkali mix together forming a new substance. A strong acid will neutralise a strong alkali and vice versa  23/2/15 22/01/2025 Starter: A bee sting is acid. What would you use to treat it and why? Chose from the pictures below  Starter: A bee sting is acid. What would you use to treat it and why? Chose from the pictures below Use toothpaste or bicarbonate of soda as a weak alkali neutralises a weak acid  Activity: Use the words below to explain how we use neutralisation for indigestion Neutralisation Stomach acid Bicarbonate of soda Indigestion Salt + water Alkali We have s________ acid to help digestion. The acid is called hydro________ a_____. When it gets to much it causes ___________. To stop this we need to neutralise the acid. We add bi_________ of soda tables which are an _________. This reacts with the acid to form ______ and _______ which are Uses of neutralization To treat acidity or gastric patients Acidity or gastric problems arise due to an increase of acid in the stomach, antacids are medicines containing bases such as NaCHO3 (sodium bicarbonate) Mg(OH)2 (magnesium hydroxide) neutralize excess of acid in the stomach. To treat acidic or basic soils Plants don’t grow well if the soil is too acidic or too basic. To neutralize acidic soils, bases like ash of burnt wood, (CaO, CaCO3) are added. Similarly, basic soils are neutralized. To treat tooth decay or cavities Most food particles are acidic in nature. E.g. lemonade, chocolate... Such foods produce acid in our mouth which reacts with enamel i.e. calcium phosphate and leads to cavities. Using toothpaste while brushing helps to neutralize the acid since toothpaste is a base.  Review We have stomach acid to help digestion. The acid is called hydrochloric acid. When it gets to much it causes indigestion. To stop this we need to neutralise the acid. We add bicarbonate of soda tables which are an alkali. This reacts with the acid to form salt and water which are  We have stomach acid to help digestion. When it gets to much we need to calm it down. We can neutralise it by adding an alkali. We add bicarbonate of soda indigestion tablets which causes a reaction With the acid forming salt and water.  What would we use to neutralise? Bee stings Bicarbonate of are ACIDIC soda (pH9) Black Coffee (pH5) Lemon Juice Bee stings are (pH2) around pH3 Water (pH7) https://www.youtube.com/watch?v=UOUN2hXvn6Y  Neutralisation 1. What colour is neutral on the pH scale? 2. If I had an acid of pH 1, what substance would neutralise it? Bleach (pH13) 3. If I had an alkali of pH 10, what acid would you use to neutralise it? Tomato Juice (pH4) 4. Which substance would What is a base? Reacting metals and acids  Recording your results Write the title of the table: Table to show observations when metals are reacted with hydrochloric acid. Draw Namethe of table below: Observations metal  Method 1. Fill a test tube a 1/3 full with acid. 2. Place one piece of metal into the acid. 3. Place your thumb over the top of the test tube to trap and collect the gas. 4. After approximately 3 minutes, take a lighted splint and put into the gas at the top of the test tube. 5. Record your observation in your table. In your table, write down your observations. Did you see bubbles? Did you observe fizzing? Was any heat produced? Did the lighted splint go “pop” when placed in the top of the tube? Bronze: Under your table, write word equations for the reactions you observed e.g. magnesium + hydrochloric acid ?+? Silver Try to write symbol equations for your word equations. Gold Try to balance your equations. Remember that hydrogen is a diatomic molecule.  Challenge: Balance These Equations Fe + H2SO4  FeSO4 + H2 Mg + HNO3  Mg(NO3)2 + H2 Zn + HCl  ZnCl + H2 When you have finished, turn these into word equations.  Metals and Acids Learning Objective: to explore what happens when a metal reacts with an acid By the end of this lesson you will be able to: Conduct a reaction between a metal and a gas Describe what happens during the reaction Represent the reaction in a word equation  Metals And Acids You are going to complete an experiment between an acid and a metal. You will follow the instructions on the sheet. Answer the questions before you start the experiment. I will assess your practical skills as I move around.  Metals and Acids Clear your table space and then collect your tray. Describe and record what each metal looks like before the experiment takes place. Measure 10ml of acid into each test-tube. Observation: what does the acid look like? Make sure your stop-clock is at ‘0’ seconds Add one metal to one test tube – start the timer when it touches the acid. Record what you see, hear, smell. When the reaction stops, stop the stop-clock. Record how long the reaction took. Repeat for the second metal. Repeat for the third metal. How To Collect A Gas  Chemical Reactions Reactants Products Reactants are the substances we begin with Products are the substances we end up with Here are two reactions. 1 What is the difference between them? 2 What do you think is happening in each one? Writing Equations Decomposition reaction Combination reaction  Writing Equations 2 Reactants Products  Naming the Salt Product aluminium + nitric acid aluminium nitrate + hydrogen aluminium + hydrochloric acid aluminium chloride + hydrogen aluminium + sulphuric acid aluminium sulphate + hydrogen  What Would These Reactions Produce? REACTANTS WORD EQUATION 1. Sodium with hydrochloric acid 2. Copper with nitric acid 3. Calcium with HOMEWORK: Word equation sheet  Metals and Acids For your practical with metals and acids, produce a word equation for the reactions. For each reaction: what were your products? What were your reactants? Look at the periodic table. Where are the metals. Can you see a pattern in the reactivity rate between metals and acids?  Reactivity Patterns Where are the three metals we used in our experiment? Could their position in the periodic table and their speed of reaction with acid help us predict the reaction rates of other metals?  Writing Chemical Equations Recall definitions of element and compounds Know general word equations for reactions of metals. Vocabulary Equation Compound Formula Reactant Symbol Product Element