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Links to other Learning Outcomes.

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Selected Learning Outcome.

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Unit of Learning.

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Lesson Plan.

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Links to JFC Key Skills.

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5 Es Instructional Model.

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Links to peer review papers: 5 Es Instructional Model.

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Links to JCT Resources.

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Acids and Bases: StudyJams! Science | Scholastic.com

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Everything in the world is an acid, a base, or neutral. This activity will teach students about how to tell whether an object is an acid, a base, or neutral.

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Indicators. Neutralisation. pH scale.

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Pure water is neutral, and so is petrol.

An is a substance that changes colour when it is added to acidic or alkaline solutions. You can prepare homemade indicators from red cabbage or beetroot juice - these will help you see if a solution is acidic or alkaline.

Litmus and universal indicator are two indicators that are commonly used in the laboratory.

Litmus

Litmus indicator solution turns red in acidic solutions and blue in alkaline solutions. It turns purple in neutral solutions.

Litmus paper is usually more reliable, and comes as red litmus paper and blue litmus paper. The table shows the colour changes it can make.

Red litmus

Blue litmus

Acidic solution

Stays red

Turns red

Neutral solution

Stays red

Stays blue

Alkaline solution

Turns blue

Stays blue

Notice how we say 'stays red'. This is better than saying 'nothing' or 'stayed the same', because it tells us the colour we actually see.

Universal indicator and the pH scale

Universal indicator is supplied as a solution or as universal indicator paper . It is a mixture of several different indicators. Unlike litmus, universal indicator can show us how strongly acidic or alkaline a solution is, not just that the solution is acidic or alkaline. This is measured using the , which runs from pH 0 to pH 14.

Universal indicator has many different colour changes, from red for strongly acidic solutions to dark purple for strongly alkaline solutions. In the middle, neutral pH 7 is indicated by green.

When you use universal indicator paper, you get more accurate results if you only put a small spot of the test solution on the paper, and then leave the colour to develop for about 30 seconds before comparing it with the colour chart.

These are the important points about the pH scale:

neutral solutions are pH 7 exactly

acidic solutions have pH values less than 7

alkaline solutions have pH values more than 7

the closer to pH 0 you go, the more strongly acidic a solution is

the closer to pH 14 you go, the more strongly alkaline a solution is

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Indicators and the pH scale - The pH scale and neutralisation - KS3 Chemistry Revision - BBC Bitesize

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Pure water is neutral, and so is petrol. An is a substance that changes colour when it is added to acidic or alkaline solutions. You can prepare homemade indicators from red cabbage or beetroot juice - these will help you see if a solution is acidic or alkaline.

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Good Teacher Revision Resource.

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Acids and bases touch upon virtually all areas of chemistry, biochemistry, and physiology. This set of lessons will get you started by presenting the underlying concepts in a systematic way. Aside from the section on pH which presumes an elementary knowledge of logarithms, there is no math here.

Note: The subject of acid-base equilibrium calculations is not covered in this lesson; for this, please see the second-semester lesson Acid-Base Equilibria and Calculations.

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Acids and bases touch upon virtually all areas of chemistry, biochemistry, and physiology. This set of lessons will get you started by presenting the underlying concepts in a systematic way. Aside from the section on pH which presumes an elementary knowledge of logarithms, there is no math here.

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Importance of Relevance.

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Neutralisation Video.

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Titrations.

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What is a Titration and how is it performed?

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Litmus Colour Change Rhyme.

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JCT- Thoughts on Inquiry Teaching and Learning.

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Thoughts on Inquiry Teaching and Learning

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Acid & Bases Student Misconceptions.

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One way to help students understand the difference between "strong" and "weak" and dilute and concentrated is to get them to carry out sequential 1:10 dilutions. Strong acid, strong base, weak acid and weak base will show that pH changes by 1 whole value for every dilution. A strong acid or base will require more dilutions to reach the same value as a weak base. This suggests that there are more particles responsible for acidity/ alkalinity present in strong acids and bases than in weak ones. This can be contrasted with concentrated solutions in which a large amount of any substance may be dissolved in water. This is independent of whether the acid/ base is "strong" or "weak", but applies equally to non-acidic substances such as sodium chloride or sugar.

Activity 5 in this Learn Chemistry resource (pages 15-20) can be used to help students to understand what is happening at the molecular level. This is Activity 5 in the Acids and Alkali's Student Pack.

The concentration of an acid or alkali is a measure of how much acid or alkali is dissolved in a known volume of liquid, e.g. water. The molarity of a solution is a measure of concentration: the number of moles dissolved in 1000cm3 of water. Concentration of solutions is usually expressed in moles per litre of solution. (A litre is the same as 1dm3 or 1000cm3.). This way of stating concentration is sometimes called 'molarity'.

In a concentrated acid or alkali there is a relatively large amount of solute dissolved, compared with a dilute acid or alkali. However, this does not tell us what the concentration of H+ ions is in the acid or OH- ions is in the alkali. This depends on the strength of the acid or alkali. Strength refers to the degree of ionisation in water.

A strong acid or alkali is one that is nearly or completely ionised in water. Examples are: hydrochloric acid, nitric acid and sulphuric acid. Sodium and potassium hydroxide are examples of strong bases.

A weak acid or alkali, on the other hand, is only partially ionised in water. Ethanoic, citric and carbonic acids are all weak acids. The ethanoic acid molecule and the ions reach a dynamic equilibrium with the equilibrium normally well to the left, so there is little H+ present.

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One way to help students understand the difference between "strong" and "weak" and dilute and concentrated is to get them to carry out sequential 1:10 dilutions. Strong acid, strong base, weak acid and weak base will show that pH changes by 1 whole value for every dilution.

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5 Es of Inquiry Explained.

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4 Levels of Inquiry Explained.

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pH Introduction

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Introduction to pH (video) | Khan Academy

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Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.

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Basic Topic Introduction.

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Kid's learn about the science and chemistry of acids and bases. pH level and reactions of chemicals.

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Reflection.