Chemical Reactions -Revision

Chemical Reactions -Revision

Read through the slides and answer the questions

Multiple Choice

The graph above is from which type of reaction?

• Endothermic reaction

• Exothermic reaction

Multiple Choice

What type of reaction is this?

• Exothermic

• Endothermic

• Energy Producing

• No way to tell

Multiple Choice

Which type of reaction does the image show?

• Exothermic

• Endothermic

Multiple Choice

Which type of reaction does the image show?

• Exothermic

• Endothermic

Multiple Choice

After you mix two substances together, a new substance forms.  This is an example of:
 

•  Physical Change
•  Chemical Change

Multiple Choice

A student mixed two chemicals to allow them to react. The temperature before the reaction was 25 ° C. The temperature after the reaction was 18° C. Which of the following is true? 

• The temperature changed 
• It is an endothermic reaction
• It is an exothermic reaction 
• Two of the answers are correct 

Multiple Choice

Sugar dissolves in water.  This is an example of....

• Physical Change
• Chemical Change

Multiple Choice

When you freeze water, it turns to ice.  What kind of change is this?

•  Physical
• Chemical

Multiple Choice

Have you ever eaten sherbet sweets candy? They fizz in your mouth and your tongue feels cold. Why do you think that is?

• It is an exothermic reaction
• It is an endothermic reaction
• It is made of ice
• It is dissolving your mouth

Multiple Choice

Is photosynthesis an exothermic or endothermic reaction?

• Endothermic
• Exothermic
• Neither

Multiple Choice

What type of reaction occurs in a hand warmer

• exothermic
• endothermic

Multiple Choice

In an endothermic reaction, heat is ...

• taken in or absorbed
• given out or released 

Complete Combustion

Complete Combustion uses lots of oxygen. Complete combustion is when a fuel burns to make carbon dioxide and water. This can be summarised as:

methane+ oxygen ➡️. carbon dioxide + water

Combustion is an exothermic reaction.

Multiple Choice

What is essential for a combustion reaction to begin?

• Carbon dioxide
• Fuel 
• Fuel, oxygen and heat
• Water and oxygen

Multiple Choice

What does this hazard symbol warn of?

• The substance is explosive

• The substance burns easily

• The substance supplies oxygen to fires

• The substance puts out fires

Multiple Choice

Combustion is a

• Natural process

• Chemical process

• Physical process

• None of these processes

Multiple Choice

Combustion is a reaction in which a substance reacts with

• hydrogen

• Nitrogen

• Oxygen

• Chlorine

Multiple Choice

What are the products of combustion?

• Hydrogen + oxygen

• Carbon dioxide + water

• Carbon dioxide + hydrogen

• Carbon + water

Multiple Choice

What do we use limewater to test for?

• Carbon Dioxide

• Water

• Heat

• Smoke

Multiple Choice

Which is the hottest part in the candle flame?

• Yellow

• Wax part

• Black

• Blue

Multiple Select

Which of these are true about combustion

• It is a physical process

• It has an exothermic reaction

• Combustion does not always result in fire

• If combustion results as fire it does not create smoke

Multiple Choice

Propane is burned with a blue flame

• propane + oxygen --> carbon dioxide + water

• propane + carbon dioxide --> oxygen + water

• propane + oxygen --> carbon monoxide + water

Incomplete Combustion

• This takes place when there is not enough oxygen present for burning

• carbon monoxide, carbon and water

Multiple Choice

Burning of charcoal in a closed room will produce

• Carbon dioxide

• Nitrogen dioxide

• Carbon monoxide

• Sulphur dioxide

Multiple Choice

This burning of methane resulted in the formation of soot

• methane + carbon monoxide --> oxygen + carbon + water

• methane + oxygen --> carbon dioxide + carbon + water

• methane + oxygen --> carbon monoxide + carbon + water

Multiple Choice

This type of combustion occurs when there is a limited supply of oxygen

• Complete Combustion

• Incomplete Combustion

Multiple Choice

If a flame is giving off smoke, this type of combustion is occurring...

• Complete combustion

• Incomplete combustion

Multiple Choice

What is NOT product of complete combustion?

• carbon dioxide

• water

• carbon monoxide

• water

Multiple Choice

What are the types of combustion?

• Complete and incomplete

• Incomplete and inexact

• Impossible and possible

• Computer and incomplete

Multiple Choice

What does incomplete combustion produce that complete combustion doesn't?

• Carbon Monoxide

• Water

• Heat

• Carbon Dioxide

Multiple Choice

Why do we burn a fuel?

• To have fun

• To release energy

• To lose energy

• To produce carbon dioxide

Oxidation

• This is a chemical reaction where oxygen is added to a substance

• When oxidation takes place an oxide is made

• An example of an oxidation reaction is when magnesium burns. A new product is made called magnesium oxide.

Oxidation

So after watching the video the reaction between magnesium and oxygen can be summarised in a word equation:-

Magnesium + oxygen ➡️ Magnesium oxide

Mg + O₂ ➡️ 2MgO

The reaction is exothermic. A lot of thermal energy was transferred to the surroundings which caused the deflagrating spoon and the glass flask to break.

The reactants of this equation are magnesium and oxygen.

The product is always found on the right hand side of the arrow. Magnesium oxide is the product.

Open Ended

What is an exothermic reaction?

Multiple Select

In an exothermic reaction energy is released to the surroundings?

• True

• False

Open Ended

What happens to magnesium when it is heated in air?

Multiple Choice

What is the name of the reaction between magnesium and oxygen

• thermal decomposition

• endothermic

• exothermic

• physical reaction

Multiple Choice

Name the gas which is needed for burning?

• carbon dioxide

• helium

• nitrogen

• oxygen

Multiple Choice

What is the product called when magnesium burns?

• magnesium

• magnesium oxide

• magnesium carbide

• magnesium dioxide

Multiple Choice

Complete the word equation:-

.............. + oxygen ➡️. magnesium oxide

• sulphur

• iron

• copper

• magnesium