3.7. Exercises

1. What are the advantages of using CNG and LPG as fuels?

CNG (Compressed Natural Gas) and LPG (Liquefied Petroleum Gas) are considered cleaner alternatives to traditional fuels like petrol and diesel. Using these fuels helps reduce harmful emissions in the atmosphere. Additionally, they are often more efficient and cost-effective for consumers, providing similar energy outputs with less environmental impact.

Imagine switching from a traditional wood-burning stove to a gas stove. The gas stove will produce less smoke and soot, which makes it better for your health and the air you breathe, just like using CNG and LPG is better for the planet.

2. Name the petroleum product used for surfacing of roads.

The petroleum product used for surfacing roads is bitumen. Bitumen is a thick, black, sticky substance that is derived from crude oil during the refining process. It is used primarily because of its binding properties and durability, making it ideal for paving roads and parking lots.

Think of bitumen like glue that helps stick pieces of gravel together to form a solid, smooth surface. Without bitumen, the asphalt on roads wouldn’t stay together and would quickly erode.

3. Describe how coal is formed from dead vegetation. What is this process called?

Coal forms over millions of years from the remains of ancient plants, particularly in low-lying wetland regions. When these plants died, they were buried under layers of soil and sediment. The heat and pressure from these layers over time transformed the plant material into coal, a process referred to as carbonisation. This lengthy process results in the concentration of carbon in coal, making it an essential fossil fuel.

Consider how composting works in gardening. Just like plant material decomposes into rich compost over time, the remains of ancient plants underwent a similar process, but under immense pressure and heat, eventually becoming coal.

4. Fill in the blanks. (a) Fossil fuels are ___, ___, and ___. (b) Process of separation of different constituents from petroleum is called ___. (c) Least polluting fuel for vehicle is ___.

This exercise encourages students to recall key facts about fossil fuels. For part (a), students would fill in coal, petroleum, and natural gas as the primary fossil fuels. Part (b) requires the term refining, which is the industrial process used to separate various components of petroleum. Finally, for part (c), students should recognize that CNG is considered the least polluting fuel for vehicles due to its cleaner combustion properties.

Think of these fill-in-the-blank exercises like a puzzle where each piece fits together to give you the full picture of fossil fuels and their importance. Understanding these basic facts is like knowing the steps to bake a cake: each step is crucial for the final result!

5. Tick True/False against the following statements. (a) Fossil fuels can be made in the laboratory. (T/F) (b) CNG is more polluting fuel than petrol. (T/F) (c) Coke is almost pure form of carbon. (T/F) (d) Coal tar is a mixture of various substances. (T/F) (e) Kerosene is not a fossil fuel. (T/F)

In this section, students are tasked with evaluating statements about fossil fuels. For each statement, they must apply their understanding to determine its validity. For example, statement (a) is false because fossil fuels cannot be artificially produced in a lab with the same conditions as in nature.

Think of this true/false exercise like a true/false quiz you might take on your favorite TV show. Just like you know the characters and the plot well enough to answer questions about them, here you are testing your knowledge on the facts about fossil fuels.

6. Explain why fossil fuels are exhaustible natural resources.

Fossil fuels are considered exhaustible because they take millions of years to form from the remains of ancient organisms. Our current rate of consumption is far outpacing the natural process of their formation, leading to a finite availability. Thus, once depleted, they cannot be replenished in a human lifetime, making responsible use essential to extend their availability.

Imagine a water faucet that you leave running while brushing your teeth. If you keep doing that without turning it off, the water will eventually run out. Similarly, using fossil fuels without conservation will lead to their depletion, as they are not being generated quickly enough to keep up with demand.

7. Describe characteristics and uses of coke.

Coke is a porous and tough form of carbon, derived from coal during its processing. It is primarily used in the production of steel and in extracting metals. Its properties make it an efficient fuel source as it burns hot and long, providing the necessary heat for metallurgical processes.

Think of coke like the charcoal used in a barbecue grill. Just like charcoal produces a hot, even flame for cooking, coke provides the intense heat needed in industrial applications such as steel-making.

8. Explain the process of formation of petroleum.

Petroleum is formed from the remains of tiny organisms in the ocean that settle on the sea floor. Over millions of years, layers of sediment buildup, compressing the remains under high pressure and heat. In this anaerobic environment (without air), these organic materials transform into petroleum through a series of complex chemical reactions.

Think of this process like making a cheese cake. You start with layers of ingredients that need to be mixed and then baked slowly in the right conditions to become something delicious. Similarly, the remains of ancient sea organisms are pressed and heated over millions of years until they transform into petroleum.

9. The following Table shows the total power shortage in India from 1991–1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis. S. No. Year Shortage (%) 1 1991 7.9 2 1992 7.8 3 1993 8.3 4 1994 7.4 5 1995 7.1 6 1996 9.2 7 1997 11.5

This exercise requires students to represent data visually using a graph, which helps in understanding trends over time. A bar graph or line graph can be used to show how power shortages in India fluctuated from 1991 to 1997, illustrating any upward or downward trends in the shortage percentage over the years.

Creating a graph from this data is like mapping out a journey on a road. Just as you can see where you've been and which paths led to where you are, a graph shows how power shortages increased or decreased over the designated years, helping make sense of the overall picture.

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