Acids and Alkalis Aim: To understand the properties of acids and alkalis To identify different chemicals as acid or alkali

Safety Some of the chemicals you will be using in this topic are HAZARDOUS. You may find various symbols on the bottles containing the acids and alkalis What do they mean? Corrosive

What do these hazard symbols mean? Harmful Irritant Flammable Toxic

Properties of Acids Strong acids are corrosive and can ‘eat away’ at materials like metal, stone and flesh! Weak acids like lemon and vinegar taste sour. Acids contain hydrogen (but not all things that contain hydrogen are acids)

Acids You will often find these acids in the science lab, however they can also be found naturally. Where else may you find them?

What type of acid do these contain? Citric acid Phosphoric acid Ethanoic acid Tannic acid Lactic acid

Properties of Bases and Alkalis They feel soapy to touch They are soluble bases Like acids they can ‘burn’ the skin Alkalis contain hydroxide ions They taste bitter

Alkalis In the science lab you will often find these alkalis. Alkalis are also present in these objects: Indigestion tablets Wasp stings Cleaning products Soap Baking soda Toothpaste

Using Indicators Aim: Use a range of different indicators to identify acids and alkalis. Explain the advantages and drawbacks of different indicators.

Using Indicators Indicators work by changing to one colour in acids and another colour in alkalis There are many different indicators, in this experiment you are going to test a few and record what colour they turn in an acidic, alkaline and neutral solution. During the experiment you will need to remember that sodium hydroxide is alkaline, hydrochloric acid is acidic and water is neutral

Results and Conclusion

Homework Make a display showing the examples of acids and alkalis you use in your home. You could: Cut out pictures from the internet. Use labels from cans, jars and bottles. Cut out pictures from magazines and newspapers.

Universal Indicator Aim: Use Universal Indicator to identify acids and alkalis. Use the pH scale to identify the strength of different acids and alkalis.

The Universal Indicator scale

Practical Work Name of Substance Colour in U.I pH Number Acid, Alkali or Neutral?

Universal Indicator Mystery Aim: Use universal indicator to identify some mystery solutions.

Universal Indicator Mystery

Results Table Solution Colour in U.I pH Label A B C D E

Making an indicator Aim: Make an indicator from a natural source. Use your indicator to identify a range of acids and alkalis. Evaluate and decide which indicator is the best and explain why.

Making an Indicator Proper pH indicator solution or paper is expensive! We can make our own, less-expensive pH indicator solution or paper using certain flowers, fruits and vegetables. Each table will be making a range of different indicators from different sources and testing each one to find out which is the best!

Results Table Indicator Colour in Acid Colour in Alkali Colour in Neutral Red Cabbage Beetroot Red Onion

Neutralisation Aim: Explain what the term Neutralisation means. Interpret graphs. Identify some everyday examples of neutralisation.

What colour will the universal indicator turn in these substances?

Neutralisation

Neutralisation Q1. What is the pH of Sodium Hydroxide? Q2. What is the pH of Hydrochloric acid? Q3. What volume of Sodium Hydroxide had to be added to neutralise the acid?

Everyday examples of Neutralisation

Everyday examples of Neutralisation

Everyday examples of Neutralisation

Everyday examples of Neutralisation

Aim: Investigate what the products of a neutralisation reaction are.

The Products of Neutralisation Mix together an acid and alkali in an evaporating basin. What two things need to be kept the same? The Concentration and Volume of the acid and the alkali needs to be the same. Using a bunsen burner, tripod, heat proof mat and gauze. Heat the evaporating basin. What will evaporate from the basin? What will be left in the basin? Water A salt

Aim: Revise the topic ready for your end of unit test. Revision Aim: Revise the topic ready for your end of unit test.

Tim and Moby Revision video