Reactions revision!

Reactions revision!

Starter copy and complete:

I can identify chemical reactions because...

Chemical reactions can be identified by

• Temperature changes

• Colour changes

• Spark/flame

• Noise

• Smell

• New substances formed

Multiple Choice

Reactions where NO new substances are made are

• Chemical reactions

• Physical reactions

Multiple Choice

Reactions that are DIFFICULT to reverse are

• Chemical reactions

• Physical reactions

Chemical vs physical reactions

Chemical reactions are difficult to reverse, physical reactions are easy to reverse

Chemical reactions create new substances, physical reactions create no new substances

Chemical reactions often involve energy transfers.

Multiple Choice

Is burning a candle a chemical or physical reaction?

• Chemical

• Physical

Multiple Choice

Is melting ice a chemical or physical reaction?

• Chemical reaction

• Physical reaction

Multiple Choice

Is burning a candle a chemical or physical reaction?

• Chemical

• Physical

Multiple Choice

Is baking a cake a chemical or physical reaction?

• Chemical reaction

• Physical reaction

Acids and alkalis

Acids and alkalis (a type of base) are two groups of chemicals involved in chemical reactions.

Alkalis can neutralise acids.

Concentrated acids and alkalis have more H+ and OH- particles in them - they are strong!

Dilute acids and alkalis have less H+ and OH- particles in them - they are weak!

Multiple Choice

What is the particle found in acids?

• H+

• OH-

• H-

• OH+

Multiple Choice

What is the particle found in alkalis?

• H+

• OH-

• H-

• OH+

Multiple Choice

What is a source of a naturally occurring acid?

• Potatoes

• Grass

• Lemons

Multiple Choice

Is soap acid or alkali?

• Acidic

• Alkaline

Multiple Choice

Is bleach acid or alkali?

• Acid

• Alkali

Multiple Choice

Is vinegar acid or alkali?

• Acid

• Alkali

Multiple Choice

What name is given to hazardous substances that can burn through substances?

• Toxic

• Corrosive

• Irritant

Testing acids and alkalis

Litmus paper and universal indicator can tell us how acidic or alkaline something is.

It uses the pH scale from 0 to 14.

Above 0 = alkaline.

Below 0 = acidic.

7 is in the middle of the scale, 7 is neutral.

Multiple Choice

A substance has a pH of 8. It is

• acidic

• alkaline

• neutral

Multiple Choice

Something tastes sour. It probably has a pH

• Above 7

• Below 7

• of 7

Multiple Choice

When acids and alkalis react together, their H+ and OH- particles form

• water

• oxygen

• hydrogen

• carbon dioxide

Making salts

Acids and alkalis also form salts when they react, as well as water.

The name of the salt has two parts.

The first comes from the METAL in the alkali

The second comes from the ACID

Naming salts

Hydrochloric acid forms salt that end with "Chloride"

Sulfuric acid forms salt that end with "sulfate"

Nitric acid forms salts that end with "nitrate"

Multiple Choice

What two products form when acids and bases react?

• Salt

• Salt and water

• Water

Multiple Choice

What name would a salt end with if hydrochloric acid made the salt?

• Nitrate

• Sulfate

• Chloride

Multiple Choice

What name would a salt end with if sulfuric acid made the salt?

• Chloride

• nitrate

• sulfate

Multiple Choice

What name would a salt end with if nitric acid made the salt?

• chloride

• nitrate

• sulfate

Multiple Choice

Which acid has Zinc chloride been made with

• nitric acid

• sulfuric acid

• hydrochloric acid

Multiple Choice

Which acid has lead sulfate been made with

• hydrochloric acid

• nitric acid

• sulfuric acid

Multiple Choice

Which acid has iron nitrate been made with

• hydrochloric acid

• nitric acid

• sulfuric acid

Multiple Choice

FINAL QUESTION

What is the correct way of writing an element helium...

• he

• HE

• He

• hE