What do you know about acids?

ACIDS

HW: Safety Poster

• Make a safety poster to display in the lab that describes how to stay safe during science experiments.

• It can be about one safety rule or as many as you want.

• Be creative!

• PLEASE PUT YOUR NAME IN THE TOP RIGHT CORNER.

Chemical ReactionsL2 Properties of Acids and Alkalis

Learning ObjectivesAll students must be able to…•Recognise some common hazard symbols and their uses

Most students should be able to…•Describe simply some properties of acids and alkalis

Some students may be able to…•Recall the names of common laboratory acids and alkalis.

• Video: Acids and Bases

• Watch the video answer the following questions:

What are acids? How are they different from bases (alkalis)?

Acids and Bases are Two Groups of Chemicals

• Chemicals can be dangerous. • Scientists use hazard symbols to label

chemicals. 

Answer the following questions.• What is hazard symbol?• Why is it important to use hazard symbols?• Draw a hazard symbol you have seen before.

Can you figure out what these hazard symbols mean?

Complete the Worksheet

• Match up the correct hazard symbol with meaning.

Acids are Corrosive

• Corrosive means that it can wear away materials

• Acids can wear away metal and even cause chemical burns when reacting with you skin!

Acids in the LabThese are three common laboratory acidsThey are called strong acids and are very dangerous.

How can we make laboratory acids safer to use?Diluting acids, adding water to them, makes them safer.

Alkalis Can also be Dangerous

• Alkalis can also burn skin and damage other materials.

• Alkalis are described as caustic.

• Just like acids, alkalis can be made safer by diluting.

Alkalis in the LabThese are two common laboratory alkalis.They are called strong alkalis and are very dangerous.

Can you figure out how to tell from the name if it is an alkali?

• Acids and alkalis are two groups of chemicals. • Are all acids and alkalis dangerous?• NO! Acids and alkalis are found in many things

we use at home!

Acid or Alkali?

•Toothpaste•Coca cola•Orange juice•Soap•Vinegar

•Milk•Water•Baking Soda•Chalk•Alcohol

Acid•Coca cola•Orange juice•Vinegar•Milk

Alkali•Toothpaste•Soap•Baking Soda•Chalk

Water and Alcohol are

neither!

Properties of Acids• Strong acids are

corrosive.• Diluted acids or

weak acids are irritants.

• React with stone and metal

• React with alkalis

• Sour taste

Properties of Alkalis• Strong alkalis

are caustic.• Diluted alkalis

or weak alkalis are irritants.

• React with acids• Bitter taste• Soapy feel

VERY DANGEROUS!

CAUSTIC!

Plenary

• Complete the worksheet “What acids and alkalis are like”

• When you finish, complete the extension “A chemical accident”