Unit 8: Chemical Reactions of Metals

Unit 8:

Chemical Reactions of Metals

Learning objectives:

These is the learning objective of this lesson:

Identify whether a chemical reaction has taken place through observations of the loss of reactants and/or the formation of products which have different properties to the reactants (including evolving a gas, formation of a precipitate or change of colour).

​A. Reactions of metals with oxygen

In Stage 7 you learned about the properties of metals. Now you are going to investigate how different metals react with oxygen

Metals and Oxygen

Many metals react with oxygen if they get hot enough. When you look carefully at the reactions of metals with oxygen, it is possible to identify which metals are more reactive. For example, magnesium is more reactive than iron because magnesium reacts more quickly than iron. This reaction between metals and oxygen is an oxidation reaction

Multiple Choice

What does REACTIVE mean?

• it means that a substance reacts actively with oxygen

• it means that a substance is not reacting to any substance

• it means that a substance is reacting but in slow progress

• it means that a substance reacts slowly then abruptly

Multiple Choice

Which one describes a type of reaction between METALS and OXYGEN?

• combustion

• oxidation reaction

• with water

• with acid

The general word equation for this reaction is:

metal + oxygen ----> metal oxide

Example:

iron + oxygen ---> iron oxide

Some metals, such as gold, do not react with oxygen. They are generally unreactive. They are described as inert. Silver reacts slowly with the air. If a silver object is not cleaned it goes black over time, as silver oxide is formed

Multiple Choice

What does INERT mean?

• reactive

• not reactive or unreactive

• proactive

• very active

The reaction between iron and oxygen

iron + oxygen ---> __________

When iron is left in damp air it rusts. The iron reacts with oxygen to form an orange-brown solid, called iron oxide. This is known as rust

Open Ended

Complete this equation from an oxidation reaction:

iron + oxygen ---> __________

​B. Reactions of metals with water

In Topic 8.3, you learned about the reactions of metals with oxygen. Now you are going to explore how different metals react with water.

The general word equation for this reaction is:

metal + water---> metal hydroxide + hydrogen

Example:

magneisum + water ---> magnesium hydroxide + hydrogen

Metals and Water

Some metals are too reactive for you to test in water. Sodium and potassium react very vigorously. They have to be stored under oil to prevent them from reacting with the water vapour in the air. In these two reactions, the metal reacted with water to produce hydrogen and the metal hydroxide

Metals and Water

metal + water ---> metal hydroxide + hydrogen

Example:

sodium + water ---> sodium hydroxide + hydrogen

Open Ended

Write the word equation for magnesium and water, by completing this equation:

magnesium + water ---> _________ + __________

C. Reactions of metals with dilute acids

Metals with dilute acids

You will probably remember the reaction of magnesium with dilute hydrochloric acid.

This is the word equation for this reaction:

magnesium + hydrochloric acid magnesium chloride + hydrogen

Magnesium chloride is an example of a salt. When a metal reacts with an acid, the products are a salt and hydrogen

Metals with dilute acids

metal + acid ---> salt + hydrogen

Example:

magnesium + hydrochloric acid --->acid magnesium chloride + hydrogen

sa

Magnesium chloride is an example of a SALT. When a metal reacts with an acid, the products are a salt and hydrogen.

Multiple Choice

Name the products between the reaction of metal and acid.

• acid and salt

• acid and hydrogen

• salt and hydrogen

• salt and water

Chemical Reactions

The end product of the reactions will help you identify which type of reactions:

oxidation reaction​	metal oxide​
metals and water​	metal hydroxide and ​hydrogen
metals and acid​	salt and hydrogen

Multiple Choice

Which type of reaction does this word equation show?

magnesium + oxygen ---> magnesium oxide

• combustion

• oxidation reaction

• metals and water

• metals and acid

Multiple Choice

Which type of reaction does this word equation show?

magnesium + hydrochloric acid ---> magnesium chloride + hydrogen

• combustion

• oxidation reaction

• metals and water

• metals and acid

Multiple Choice

Which type of reaction does this word equation show?

sodium + water ---> sodium hydroxide + hydrogen

• combustion

• oxidation reaction

• metals and water

• metals and acid

Multiple Choice

Complete the equation below:

magnesium + _______ ---> magnesium oxide

• hydrogen

• water

• oxide

• oxygen

Multiple Choice

Complete the equation below:

sodium + water ---> ______ + hydrogen

• sodium hydroxide

• water

• calcium chloride

• magnesium chloride

Multiple Choice

Complete the equation below:

magnesium + hydrochloric acid ---> ______ + hydrogen

• sodium chloride

• water

• calcium chloride

• magnesium chloride

Multiple Choice

Combustion, oxidation reaction, metals and water, metals and acid are all example of which type of chemical reaction?

• endothermic

• exothermic