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Acids and Alkalis: Common Household Substances and Hazards

Learn about common acids and alkalis used at home, identify substances as acids or alkalis, and understand hazard symbols for dangerous chemicals.

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Acids and Alkalis: Common Household Substances and Hazards

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  1. CKS3: Yr7 Chemistry Unit 1 – Me the the Scientist!Lesson number: 4. Lesson Title: Acids and Alkalis • Connector: • List 3 common acids and 3 common alkalis and how they are used at home. Cro2011

  2. New Information for Task 1 • Acids and alkalis are groups of chemicals. ALKALI ALKALI ACID ACID ALKALI NEUTRAL ACID

  3. Acids and alkalis When a substance dissolves in water it makes a solution. Solutions can be sorted by whether they are: acid, alkali or neutral. http://www.bbc.co.uk/learningzone/clips/universal-indicator-acid-alkali-or-neutral/121.html

  4. New Information for Task 1 Some facts about acids and alkalis

  5. BIG picture Key Question: How can you determine if a chemical is an acid or an alkali? What skills will you be developing this lesson? HSW- by planning and carrying out an investigation/ Interpreting data/ evaluating an experiment ICT- through using laptops Numeracy- by using formulae in calculations Literacy- by writing explanations using correctly spelt keywords and good grammar. Team work- during a practical investigation Self management- by completing an individual assignment by ….. Creative thinking- by designing a ………………. Independent enquiry- by researching the internet Participation- during a practical activity Reflection- through self and peer assessment of each outcome How is this lesson relevant to every day life? There are many acids and alkalis present in our everyday lives. Quick Discussion: What do you already know?

  6. Keywords: Create sentences using the keywords to show that you know what they mean. Put your hand up if there is any key word from the list that you don’t understand. • Acid • Alkali • Solution • pH • Indicator • Universal Indicator • Sour taste • Soapy feel • Caustic • Irritant • Strong • Weak • Corrode • hazardous

  7. New Information for Learning Outcome 1 • Visual: Demonstration • http://www.bbc.co.uk/learningzone/clips/universal-indicator-acid-alkali-or-neutral/121.html • Audio: Demonstration • Kinaesthetic: Class experiment

  8. What is the pH scale? The strength of an acid or alkali is measured by the pH scale. Each universal indicatorcolour is given a number called the pH value. Universal indicator can tell you the pH of a solution. strongeracid stronger alkali 1 2 3 4 5 6 7 8 9 10 1112 1314 strongacid weak alkali weakacid strongalkali neutral What is the pH of a weak acid? What is the pH of strong alkali? Copy into books

  9. Task 1 (Level 5) • Task 1: • Predict from the range of household substances which ones you think are acids and alkalis, write them down in predictions • Task 1: Extension • Group the substances into strong and weak acids and strong and weak alkalis • Keywords for Task 1: • Acid • Alkali • Weak Acid • Weak Alkali • pH • Universal indicator

  10. Copy and complete

  11. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 acid alkali What type of substance? Are these substances acidic or alkaline? Are they weak or strong? very weak acid very strong acid very weak alkali weak alkali strong acid very strong alkali weak acid

  12. Create Evaluate Analyse Apply Understand Remember Demonstrate your Learning for Outcome 1 I am working at level .... because ........... Apply (L5) Can you use a storey board to explain how to identify if a household substance is an acid, alkali or neutral Understand (L4) Did you: Complete the experiment ? Can you classify different household substances into acid or alkali?

  13. Extended Learning Extended Learning task: • Make a poster display of all the different acids and alkalis in the home and their different uses. • e.g. Vinegar is an acid and it can be used in homes to make pickles. Due date: Criteria for Level 5: • Basic description, basic detail. Criteria for Level 6: • Description with explanation and good level of detail. Criteria for Level 7: • Detailed description and in depth detailed explanation using examples to highlight points made.

  14. Learning Outcome 1: Review To carry out an experiment to identify and classify household substances into acids and alkalis Go back to your Learning Outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

  15. New Information for Learning Outcome 2 What are hazard symbols? How can you tell which chemicals are safe and which are dangerous? Special symbols are used on bottles and vehicles that contain dangerous chemicals. corrosive toxic irritant harmful highly flammable These hazard symbols show why the chemical is dangerous. Why is it important that these symbols can be recognised by people from other countries?

  16. 7E Acids and alkalis - Concentrated and dilute concentrated acid weak acid Compare the particle model of a concentrated acid with a weak acid. Which sentence best describes which acid? A. This acid has only a few acid particles compared to water particles. B. This acid has a lot of acid particles compared to water particles. Why is a dilute acid less hazardous than a concentrated acid?

  17. Create Evaluate Analyse Apply Understand Remember Demonstrate your Learning for Outcome 2 I am working at level .... because ........... To get to the next level I need to ........... Analyse (L6) Did you: Draw a poster to identify hazard warning symbols Include pictures of the chemicals and information about how to use it safely in the lab? Explain why dilute acid is less hazardous Apply (L5) Did you: Do a storey board to explain what happen when UI is added to a substance Identify the colour change with UI?

  18. Learning Outcome 2: Review To carry out an experiment to investigate the heating effect of different bunsen flames. Go back to your Learning Outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

  19. Learning Activities for Outcome 3 Extension – Linking the strength of an acid to how corrosive it is Task 7: Draw a line, and add substances to it to show how hazardous or corrosive you think the household substances are Task 2: Extension Name a very harmful acid and very harmful alkali

  20. Task 3: Answers Not harmful Weak acids and alkali and neutral Harmful and corrosive Strong acids and Alkalis

  21. Learning Outcome 3: Review Go back to your Learning Outcome grid and fill out the ‘How I did’ and the ‘Targets’ column.

  22. Review for Remembering • Stand up if you have met the lesson outcomes? • If not what do you need to do next in order to meet the outcome? Record this in your diary as part of your homework. • Is there any part of the lesson you think you need to go over again next lesson? • Tell the person next to you three things you have learnt this lesson. • How will you remember this for your exam?

  23. Technician’s list Apparatus and chemicals Eye protection Universal Indicator• fizzy drinks• tap water • de-ionised/distilled water • toothpaste• shampoo • soap• vinegar • lemon juice Technical notes 1 Provide small amounts of the samples on watch glasses. The watch glasses can be placed on a white tile marked with the name of the substance - use a waterproof marker. 2 The samples can be arranged around the room so that the students visit each in turn. If any solid sample is used, moisten it with a little de-ionised water.

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