7E ACIDS AND ALKALIS

The pH scale• What is the pH scale?

• What pH does an acid have?

• What pH does an alkali have?

• What is the neutral pH

The pH ScaleA way to measure how acidic or alkaline a

substance is

Universal indicator paper shows a different colour for each pH

Indicators

• What is an indicator?

• Which indicator has many different colours?

• Name some other indicators.

Acids and alkalis in the Science lab

• Which hazard symbols might acids or alkalis have?

• What should you do if you get acid or alkali on your skin? Why?

• Name two acids and two alkalis you might use in the science lab.

The power of acids

• http://youtu.be/kcDSngXldB0• http://youtu.be/F5jfRjzXLbE

• Looking at acids and alkalis in the lab

Acids and alkalis in the lab

More acids and alkalis

• Card sort

Indicators

• What is an indicator?

• Name 3 indicators.

Things to do:1. Write a method for the experiment2. Do a diagram of the experiment3. Make your indicator and write about it is the table

Colour in acid Name of indicator Colour in alkali

Acid rain

• What is acid rain?

• Which gases cause acid rain?

Next

• Draw a diagram to show how acid rain is formed

Answer the questions

• Do you think that the acid rain problem in the UK is over or not? Explain your answer with evidence from your work.

• How can countries try to solve the acid rain problem?

Neutralisation

• What is neutralisation?

• Complete this formulaAcid + Alkali →

• Name 3 examples of when neutralisation is useful.

NeutralisationPut 8cm3 of alkali in a test tubeAdd 1 cm3 of acid, stir and remove a drop of liquidTest the pHWash the dropperAdd 1 cm3 more of acid

Volume of acid (cm3) pH

0

1

2

3

4

5

…

Your task is to design a page in a family health book all about insect

stings and how to treat them.

Step 1

Find out the pH of wasp and bee stings.

Insect sting

Colour with universal indicator

pH

Wasp

Bee

Step 2

To get rid of an insect sting you need to neutralise it. What pH will neutralise the:

a) Wasp sting?

b) Bee sting?

Step 3

Find out the pH of these household chemicals.

Chemical Colour with universal indicator

pH

Vinegar

Water

Bicarbonate of soda

Step 4

Which chemical would you use to treat the:

a) Wasp sting?

b) Bee sting?

Step 5

Design your book page on plain A4 paper. Try to find out this extra info: What are the chemicals in wasp and bee stings?