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Starter: Complete this spider diagram in your books writing absolutely everything you think you know about the topicWhat I know about Acids and AlkalisAcids and AlkalisLearning objectives

Be able to explain that an indicator shows the pH of a substance when added to it and that there are different types.

Be able to explain the difference between an acid and an alkali and base with examples.

Be able to give some real life examples of indicators. Think, pair, share: match up the definitions.AcidBaseAlkaliSubstances with a pH of less than 7.Turn blue litmus paper red. They turn universal indicator red if they are strong, and orange or yellow if they are weak.They are usually metal oxides or metal hydroxides. For example, copper oxide and sodium hydroxide. These are soluble. Have a pH of more than 7. Turn red litmus paper blue. They turn universal indicator dark blue or purple if they are strong, and blue-green if they are weak. Sodium hydroxide is an example. An acid is a substance with a pH of __________ ________7. It will turn universal indicator red if they are ___________, and orange or yellow if it is weak. Acids often taste _________ and many acids can be _________________ if you touch them. Lemon juice and _________________ are examples and _________________ acid is a very strong acid found in your ___________. You can use blue_________________ paper to determine if something is acid or not because the acid will turn the paper red.

Bases are usually metal oxides or metal __________ . For example, copper oxide and sodium hydroxide. Bases feel _________________ when you touch them and taste _________________. Many household cleaners are bases. Some bases can even dissolve hair and food, which makes them ideal for clearing clogged drains.

Alkalis: are soluble ________. Have a pH of __________ _________7. They turn red litmus paper blue and turn universal indicator dark blue or purple if they are strong, and blue-green if they are _________. Sodium hydroxide is an example.

weakbittercorrosivedigesthydrochloricstrongstomachhydroxideslitmusLess thansoapysourMore thanvinegar less thanstrongsourcorrosivevinegarhydrochloricstomachlitmushydroxidessoapybitterbasesmore thanweakDetecting Acids and AlkalisWhat is an indicator?We use special chemicals called indicators to determine if a substance is acidic, alkaline or neutral.These turn different colours in acids, alkalis and neutral solutions.

Natures indicators

SolutionColour in red cabbage indicatorAcid/ Alkali/Neutral

Stong/Weak?Label?ABCDEStrong AcidWeak AcidNeutralWeak alkaliStrong alkali

In pairs, take one pestle and mortarwith 1-2 slices red cabbageMix with the mortarPound with the pestle

Mix with the mortarPound with the pestleCut up the cabbage into small pieces with scissors and add a small splash of warm water1 1 Min 15 SecsStart Timer

Grind the red cabbage

Now add another splash of warm water and mix gently. Pipette out the purple liquid into a clean beaker. You have just made an indicator!Well plateSafety! Safety glasses protect your eyes! Hair tied backStand up at all timesBags, coats and chairs under desksMove around the classroom and handle equipment sensibly.

DO NOT MIX PIPPETES WITH LIQUIDS!!!!

Testing for acids and alkalis.Use your pipette to add about 0.5mls of the sample you want to test to the well plate.Add a few drops of your cabbage indicator.Record the colour the indicator changes to.Use your observations to predict whether each substance is acid, alkali and neutral.Try and match the labels to the unknown liquids.

Red cabbage indicatorWell plateOnce you have completed testing your samples1. Write up your experiment i) describing how you made your red cabbage indicator and ii) explaining how it can be used to detect acidic, alkaline and neutral substances. 2. Make a list of safety rules for a new Year 7 class who have never handled acids or alkalis before. What are the hazards, what should they wear, what if they spill it on themselves?3. A lorry carrying concentrated sulfuric acid spills it all over a section of motorway. Advise the police on how they could deal with this dangerous chemical and make the motorway safe again. Write down what you would say to them.Plenary true or falsepH 8 is a strong alkali.TRUEFALSEPlenary true or falseA weak acid would be red.TRUEFALSEPlenary true or falseA strong alkali would be purple.TRUEFALSEPlenary true or falseLight green would be pH 5.TRUEFALSEPlenary true or falseAn acid is a soluble base.TRUEFALSEPlenary true or falseThe acid in your stomach is hydrochloric.TRUEFALSEPlenary true or falseSodium hydroxide is an example of an alkali.TRUEFALSEPlenary true or falseA strong acid would be pH 1-4.TRUEFALSEPlenary true or falseIf you mixed an acid with an alkali they would cancel each other out?TRUEFALSEBenny HillThe Edwin Davids Jazz BandLes meilleurs gnriques de l'histoire de la tl, Vol. 2, track 14, disc 1/12007Soundtracks66375.805eng - Amazon.com Song ID: 216178946