Oxidation and combustion

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Lesson notes

Oxidation

**Oxidation** is a chemical reaction where a substance **gains oxygen**.
General equation: **metal + oxygen → metal oxide**.
Reactants are on the left, products on the right of the arrow.
Examples: **iron + oxygen → iron oxide**; **copper + oxygen → copper oxide**.

Combustion

**Combustion** is the scientific term for **burning** a fuel.
Fuels are often **hydrocarbons** – compounds of **hydrogen and carbon**.
Three requirements: **oxygen**, **heat**, and **fuel** – shown in the **fire triangle**.

Complete Combustion

Occurs when there is **plenty of oxygen**.
General equation: **fuel + oxygen → carbon dioxide + water**.
Example: **propane + oxygen → carbon dioxide + water**.
Products are **carbon dioxide** and **water** (both harmless in normal amounts).

Incomplete Combustion

Occurs when there is **not enough oxygen**.
General equation: **fuel + oxygen → carbon monoxide + water**.
Produces **carbon monoxide**, a **poisonous**, **colourless**, **odourless** gas.
Dangerous because it is hard to detect; **carbon monoxide detectors** are used for safety.

Particle arrangement in solids, liquids, and gases – relevant to the reactants and products in combustion (oxygen as gas, fuel as liquid or gas).

Slides

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Practice questions

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1.What is oxidation?
Easy
- AA substance gains oxygen
- BA substance loses oxygen
- CA substance gains hydrogen
- DA substance loses hydrogen
2.In the word equation 'magnesium + oxygen → magnesium oxide', which are the reactants?
Easy
- AMagnesium and oxygen
- BMagnesium oxide only
- COxygen only
- DMagnesium only
3.What is the scientific word for burning a fuel?
Easy
- ACombustion
- BOxidation
- CDecomposition
- DRusting
4.What are the three requirements for combustion to occur?
Easy
- AOxygen, heat, and fuel
- BOxygen, water, and fuel
- CHeat, fuel, and carbon dioxide
- DOxygen, heat, and carbon dioxide
5.What elements do hydrocarbons consist of?
Easy
- AHydrogen and carbon
- BHydrogen and oxygen
- CCarbon and oxygen
- DCarbon, hydrogen, and oxygen
6.What are the products of complete combustion of a hydrocarbon?
Medium
- ACarbon dioxide and water
- BCarbon monoxide and water
- CCarbon and water
- DCarbon dioxide and hydrogen
7.What are the products of incomplete combustion of a hydrocarbon?
Medium
- ACarbon monoxide and water
- BCarbon dioxide and water
- CCarbon and water
- DCarbon monoxide and hydrogen
8.Why is incomplete combustion dangerous?
Medium
- AIt produces carbon monoxide, which is poisonous, colourless, and odourless
- BIt produces carbon dioxide, which is a greenhouse gas
- CIt produces soot, which is harmful to breathe
- DIt uses up oxygen in the room

More questions

9.When does incomplete combustion typically occur?
Medium
- AWhen there is insufficient oxygen
- BWhen there is excess oxygen
- CWhen the fuel is not heated enough
- DWhen water is present
10.Which word equation represents the complete combustion of propane?
Hard
- Apropane + oxygen → carbon dioxide + water
- Bpropane + oxygen → carbon monoxide + water
- Cpropane + oxygen → carbon + water
- Dpropane + oxygen → carbon dioxide + hydrogen
11.What is the product when magnesium undergoes oxidation?
Hard
- AMagnesium oxide
- BMagnesium hydroxide
- CMagnesium carbonate
- DMagnesium chloride
12.Which of the following is an example of oxidation?
Hard
- Airon + oxygen → iron oxide
- Bmethane + oxygen → carbon dioxide + water
- Ccalcium carbonate → calcium oxide + carbon dioxide
- Dwater → hydrogen + oxygen
13.A student heats a strip of copper in a Bunsen burner. The copper changes from brown to black. What word equation represents this reaction?
Medium
- Acopper + oxygen → copper oxide
- Bcopper + carbon dioxide → copper carbonate
- Ccopper + heat → copper oxide
- Dcopper + water → copper hydroxide
14.A factory burns methane as a fuel. In a well-ventilated furnace, which are the products of this combustion?
Medium
- Acarbon dioxide and water
- Bcarbon monoxide and water
- Ccarbon and water
- Dcarbon dioxide and hydrogen
15.A gas heater in a poorly ventilated room may produce a poisonous gas. What is this gas?
Medium
- Acarbon monoxide
- Bcarbon dioxide
- Coxygen
- Dmethane
16.A student burns 16 g of methane (CH₄) completely in excess oxygen. Using the equation CH₄ + 2O₂ → CO₂ + 2H₂O, what mass of carbon dioxide is produced? (Relative atomic masses: C=12, H=1, O=16)
Hard
- A44 g
- B16 g
- C32 g
- D22 g
17.Which of the following is a hydrocarbon?
Easy
- Amethane
- Bcarbon dioxide
- Cwater
- Doxygen
18.When a fuel burns with a yellow, smoky flame, what is likely happening?
Medium
- Aincomplete combustion due to limited oxygen
- Bcomplete combustion with excess oxygen
- Cthe fuel is not a hydrocarbon
- Dthe fuel is pure carbon
19.A student investigates the mass change when iron wool is heated in air. The iron wool gains mass. What is the best explanation?
Hard
- AIron reacts with oxygen to form iron oxide, adding mass.
- BIron reacts with nitrogen to form iron nitride.
- CThe heat causes the iron to expand.
- DWater from the air condenses on the iron.
20.In the reaction magnesium + oxygen → magnesium oxide, what are the reactants?
Easy
- Amagnesium and oxygen
- Bmagnesium oxide only
- Coxygen only
- Dmagnesium only
21.Which of the following is a product of incomplete combustion of a hydrocarbon?
Medium
- Acarbon monoxide
- Bcarbon dioxide
- Coxygen
- Dhydrogen
22.A sample of air is analysed after a gas fire has been running in a sealed room. Which gas is likely to be present at a dangerous level due to incomplete combustion?
Hard
- Acarbon monoxide
- Bcarbon dioxide
- Coxygen
- Dnitrogen
23.What three things are needed for combustion?
Easy
- Aoxygen, heat, fuel
- Boxygen, water, fuel
- Cheat, fuel, carbon dioxide
- Doxygen, heat, carbon dioxide
24.The word equation for the complete combustion of propane is: propane + oxygen → carbon dioxide + water. Which substance is the fuel?
Medium
- Apropane
- Boxygen
- Ccarbon dioxide
- Dwater
25.A student heats a piece of copper in a Bunsen burner. The copper changes from brown to black. Which of the following word equations represents the reaction taking place?
Medium
- Acopper + oxygen → copper oxide
- Bcopper + heat → copper oxide
- Ccopper + carbon dioxide → copper oxide
- Dcopper + water → copper oxide
26.A student investigates the mass change when iron wool is heated in air. The iron wool gains mass. What is the best explanation for this?
Medium
- AIron reacts with oxygen to form iron oxide, which has a greater mass than iron alone.
- BThe iron wool absorbs water vapour from the air.
- CThe heat causes the iron to expand, increasing its mass.
- DThe iron wool loses impurities, making it heavier.
27.Which of the following is the correct word equation for the oxidation of magnesium?
Easy
- Amagnesium + oxygen → magnesium oxide
- Bmagnesium + water → magnesium hydroxide
- Cmagnesium oxide → magnesium + oxygen
- Dmagnesium + carbon dioxide → magnesium carbonate
28.What is the product when calcium undergoes oxidation?
Easy
- Acalcium oxide
- Bcalcium hydroxide
- Ccalcium carbonate
- Dcalcium chloride
29.Which word equation represents the complete combustion of methane?
Hard
- Amethane + oxygen → carbon dioxide + water
- Bmethane + oxygen → carbon monoxide + water
- Cmethane → carbon + hydrogen
- Dmethane + water → carbon dioxide + hydrogen
30.A student heats a known mass of copper powder in a crucible and measures the mass after heating. The mass increases by 0.16 g. Assuming all the copper reacts to form copper oxide, what mass of oxygen combined with the copper?
Medium
- A0.16 g
- B0.08 g
- C0.32 g
- D0.04 g
31.A student investigates the combustion of methane in a closed container. After the reaction, the container contains carbon dioxide, water vapour, and some unreacted methane. What type of combustion occurred?
Hard
- AComplete combustion
- BIncomplete combustion
- COxidation only
- DNo combustion
32.A fuel contains only carbon and hydrogen. When it burns completely in a plentiful supply of oxygen, which two products are formed?
Medium
- ACarbon monoxide and water
- BCarbon and water
- CCarbon dioxide and water
- DCarbon dioxide and hydrogen
33.A student places a glowing splint into a gas jar containing a colourless gas. The splint relights. Which gas is most likely present?
Medium
- ACarbon dioxide
- BOxygen
- CCarbon monoxide
- DNitrogen
34.A 0.50 g sample of magnesium is burned in excess oxygen to form magnesium oxide. The mass of magnesium oxide produced is 0.83 g. What is the mass of oxygen that combined with the magnesium?
Hard
- A0.33 g
- B0.50 g
- C0.83 g
- D1.33 g
35.Which of the following is the correct word equation for the oxidation of iron?
Easy
- Airon + oxygen → iron oxide
- Biron + water → iron oxide
- Ciron + carbon dioxide → iron oxide
- Diron + hydrogen → iron oxide
36.A student sets up an experiment to show that oxygen is used up during combustion. They place a burning candle in a sealed jar and measure the volume of gas in the jar before and after the candle goes out. Which gas volume will decrease?
Medium
- AOxygen
- BCarbon dioxide
- CNitrogen
- DWater vapour
37.0.24 g of magnesium reacts completely with oxygen to form 0.40 g of magnesium oxide. What is the mass of oxygen that reacted?
Hard
- A0.16 g
- B0.24 g
- C0.40 g
- D0.64 g
38.A student investigates the mass change when a piece of iron wool is heated in a sealed container. The mass of the container and iron wool before heating is 50.00 g. After heating and cooling, the mass is 50.00 g. Why did the mass not change?
Medium
- ANo reaction occurred
- BThe iron wool lost mass equal to the oxygen gained
- CThe container is sealed so no matter can enter or leave
- DThe iron wool did not react with oxygen
39.What is the name given to the burning of a fuel?
Easy
- AOxidation
- BCombustion
- CEvaporation
- DCondensation
40.A student places a piece of burning magnesium ribbon in a gas jar of carbon dioxide. The magnesium continues to burn. Which element in the carbon dioxide is reacting with the magnesium?
Medium
- ACarbon
- BOxygen
- CBoth carbon and oxygen
- DNeither

Revision notes

## Oxidation and Combustion ### Oxidation - **Definition**: Oxidation is when a substance gains oxygen. - **General equation**: metal + oxygen → metal oxide - **Examples**: - iron + oxygen → iron oxide - copper + oxygen → copper oxide ### Combustion - **Definition**: Combustion is the scientific word for the burning of a fuel. - **Requirements**: Three things are required for combustion – oxygen, heat, and fuel (fire triangle). - **Fuel**: A fuel is generally made of hydrogen and carbon; a compound of hydrogen and carbon is called a **hydrocarbon**. #### Complete Combustion - **Occurs when**: There is enough oxygen. - **General equation**: fuel + oxygen → carbon dioxide + water - **Example**: propane + oxygen → carbon dioxide + water #### Incomplete Combustion - **Occurs when**: There is not enough oxygen. - **General equation**: fuel + oxygen → carbon monoxide + water - **Danger**: Carbon monoxide is a poisonous, colourless, and odourless gas. Carbon monoxide detectors can be used for safety. ### Key Points - Reactants are on the left of the equation, products on the right. - Incomplete combustion is dangerous because carbon monoxide is hard to detect.

Oxidation: A chemical reaction where a substance gains oxygen.
Combustion: The scientific word for the burning of a fuel.
Hydrocarbon: A compound of hydrogen and carbon.
Complete combustion: Combustion with enough oxygen, producing carbon dioxide and water.
Incomplete combustion: Combustion with insufficient oxygen, producing carbon monoxide and water.
Carbon monoxide: A poisonous, colourless, and odourless gas produced by incomplete combustion.

Flashcards

What is oxidation?

Oxidation is when a substance gains oxygen.

General equation for a metal undergoing oxidation.

metal + oxygen → metal oxide

What are reactants in a chemical equation?

Reactants are the substances that undergo a reaction, written on the left side.

What are products in a chemical equation?

Products are the substances formed by the reaction, written on the right side.

Word equation for iron oxidation.

iron + oxygen → iron oxide

Word equation for copper oxidation.

copper + oxygen → copper oxide

What is combustion?

Combustion is the scientific word for the burning of a fuel.

What is a hydrocarbon?

A compound of hydrogen and carbon.

Three things required for combustion (fire triangle).

Oxygen, heat, and fuel.

Two types of combustion.

Complete combustion and incomplete combustion.

General equation for complete combustion.

fuel + oxygen → carbon dioxide + water

Products of complete combustion.

Carbon dioxide and water.

Specific example of complete combustion (propane).

propane + oxygen → carbon dioxide + water

When does incomplete combustion occur?

When there is not enough oxygen available.

General equation for incomplete combustion.

fuel + oxygen → carbon monoxide + water

Products of incomplete combustion.

Carbon monoxide and water.

Why is incomplete combustion dangerous?

Carbon monoxide is a poisonous, colourless, and odourless gas, making it difficult to detect.

How can carbon monoxide be detected in homes?

Carbon monoxide detectors sound an alarm if levels are too high.

Word equation for magnesium oxidation.

magnesium + oxygen → magnesium oxide

Word equation for calcium oxidation.

calcium + oxygen → calcium oxide

Word equation for aluminium oxidation.

aluminium + oxygen → aluminium oxide

Complete combustion of methane.

methane + oxygen → carbon dioxide + water

Complete combustion of ethane.

ethane + oxygen → carbon dioxide + water

Complete combustion of butane.

butane + oxygen → carbon dioxide + water

Incomplete combustion of methane.

methane + oxygen → carbon monoxide + water

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