Chemistry A1 - Relating properties to uses and production of substances

Textbook

Common name for aluminium oxide?

Alumina

One property of alumina?

It is amphoteric

What does amphoteric mean?

A substance that can act as both an acid or a base, depending on the conditions

What does base mean?

A compound that reacts with an acid to form a salt and water

What does acid mean?

A compound containing hydrogen that dissociates in water to form hydrogen ions

What does aluminium oxide react with hot hydrochloric acid give?

Aluminium chloride and water

What is the aluminium chloride?

Soluble

Equation for the above statement?

Al2O3 + 6HCL → 2AlCl3 + 3H2O

Aluminium oxide is chemically inert except under certain conditions. Give an example

When a hot acid or base is present.

What does that mean?

It means that it has a lot of uses which includes filler, paint, sunscreens, and glass.

What does the amphoteric nature of alumina mean?

It means that it can be used as a medium for chromatography as a basic, acidic, or neutral medium

What is alumina also?

An effective desiccant

What range can it be used at?

A range of basic and acidic pHs

At what range is it stable at?

Stable over pH range 2-13

For what does it make suitable for?

Environmental clean-up and separation applications

What are group 1 and 2 metal oxides?

Basic

What happens when they dissolve in water?

They will react with the water to form metal hydroxides

What does that form?

An alkali solution

Select the 1 correct example for an alkali solution

Na2O + H2O - > 2NaOH

Select the other correct example for an alkali solution

CaO + H2O - > Ca(OH)2

What is an alkali?

A base that dissolves in water to form hydrogen ions

What is the oxide ion?

A very strong basic anion

This is due to?

It very small size and high (-2) charge

What does the oxide ion in the metal oxide react with water to produce?

Hydrogen ions

Why?

Because a hydroxide ion is the strongest base that can persist in water

What is another name for calcium oxide?

Quicklime

What does calcium oxide react with water to form?

Calcium hydroxide

Another name for calcium hydroxide?

Lime

What can calcium hydroxide be used for?

Used by farmers to raise the pH of acidic soil

What can magnesium oxide be used for?

As a desiccant when preserving books in a library

Is magnesium oxide a good desiccant?

No

Why is it used for?

Used because due to its basic nature, it will neutralise the acidic sulfur oxides produced, so it helps preserve the book.

How is sodium hydroxide produced?

Sodium oxide reacts with water

What is it used for?

Used in some processes to make plastics and soaps

Another use?

Used in food processing in many ways

Examples?

To peel fruits and to process cocoa and chocolate

Where is it found?

In drain cleaner or in oven cleaner

What is magnesium hydroxide also known as?

Milk of magnesia

What is it used for?

Treating acid indigestion

How?

Raises the stomach pH

Due to?

Its basic nature

What is calcium hydroxide used for?

In the treatment of acidic effluent

Factories that produce or used sulfuric acid also produce?

Acidic liquid effluent

Does it need to be treated before released to the environment

Yes, especially if it has high acid content

Impurities are precipitated and removed. The acidic liquid can be neutralised using?

Calcium hydroxide

What is the reaction for this?

H2SO4 + Ca(OH)2 → CaSO4 + 2H2O

What is the calcium hydroxide?

Base

What is formed?

Neutral calcium sulfate

What is calcium sulfate?

A salt

Why is calcium hydroxide used?

Cheap and simple to use

What does salt mean?

A compound formed by an acid-base reaction where the hydrogen in the acid has been replaced by a metal (or other positive) ion

What is electrolysis?

The decomposition of a compound using electricity

What does electrolysis break down?

Compounds into simple substances

Where is it used for?

In some industrial processes

Ionic substance are…

Decomposed by an electrical charge being passed through them during electrolysis

How must the ions be to be able to do this?

Must be free to move for this work

How must the compound be?

Either molten or in solution

What is molten?

Reduced to liquid form by heating

What is produced by this reaction?

Only sodium and chloride