3. Petroleum is found in the purest form under the Earth's crust. 4. Oxygen gas is produced when coal burns. 5. Coke is harder and denser than charcoal.
Answer (1)
Let's look at each statement one by one and understand them in the context of their chemical nature:
Petroleum is found in the purest form under the Earth's crust.
Petroleum , also known as crude oil, is a complex mixture of hydrocarbons and other organic compounds. It is not found in its purest form under the Earth's crust because it always contains a mix of different substances. In fact, petroleum needs to be refined before it can be used effectively, which involves separating it into usable components like gasoline, diesel, and other byproducts.
Oxygen gas is produced when coal burns.
The combustion of coal does not produce oxygen gas. When coal burns, it primarily reacts with oxygen from the air to produce carbon dioxide (CO₂) and heat energy. The chemical equation for the combustion of coal, which is mainly carbon, can be written as:
C + O 2 → CO 2 + heat energy
So instead of producing oxygen, it consumes oxygen from the atmosphere.
Coke is harder and denser than charcoal.
Coke and charcoal are both carbon-rich substances, but they differ in their production and properties. Coke is produced from coal through a process called destructive distillation in the absence of air. Charcoal is made by heating wood in a low-oxygen environment. Coke is indeed harder and denser than charcoal, which makes it suitable for use in metal production, particularly in blast furnaces, due to its high carbon content and energy efficiency.
