Answer key

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Last edited 25 days ago by Learn LoopHQ.

Chapter: 06. Air And Atmosphere

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In respiration, oxygen reacts with digested food (glucose) to produce carbon dioxide, water, and energy necessary for all bodily activities.

Aquatic animals obtain oxygen from the air that is dissolved in water.

Air helps to dry clothes and grains.

When plants and animals die, they decay, and their nitrogen compounds are returned to the soil, which helps balance the amount of nitrogen in nature.

Glucose + Oxygen → Carbon dioxide + Water + Energy

Respiration takes place at body temperature, while burning takes place at a higher temperature.

We can feel the presence of air when it moves, which is then called wind.

The atmosphere maintains the temperature on Earth, preventing extreme burning or freezing conditions that would make life impossible.

Petrol and kerosene are two products obtained from petroleum.

The burning of fuels consumes oxygen from the air and releases carbon dioxide, impacting the natural balance by taking one gas and producing the other.

Ethyl mercaptan is added to LPG to give it a strong smell, which helps to detect any gas leakage for safety reasons, as LPG itself is odorless.

Smog is a type of air pollution that reduces the visibility on roads, frequently leading to road and train accidents.

When an inverted glass submerged in water is tilted, the air trapped inside the glass escapes in the form of bubbles, allowing water to enter and fill the space.

The components of air can be separated by simple physical methods, whereas components of a compound can only be separated by chemical methods.

Oxygen supports burning; without it, substances cannot combust.

One simple measure an individual can take is to grow more and more trees, as they absorb carbon dioxide and release oxygen.

Chlorophyll is the green pigment in plants that absorbs sunlight, which is necessary for the process of photosynthesis where plants make their food.

Air has mass and it occupies space.

The presence of oxygen (air) and water vapour (moisture) are necessary for rusting.

Organisms like earthworms come out of the soil during heavy rains because the soil gets filled with water, reducing the air trapped between soil particles, forcing them out to breathe.

Coal is a fossil fuel formed over millions of years from the remains of living organisms, and it is obtained from coal mines.

The limewater in flask B turns milky because the potted plant inside the bell jar respires, producing carbon dioxide, which then reacts with the limewater.

Plants use carbon dioxide to make their food through the process of photosynthesis.

When water is added to soil, small bubbles are observed, indicating the presence of air trapped between the soil particles.

Two natural causes of air pollution are volcanic eruptions and forest fires.

CNG is preferable for vehicles to reduce air pollution because it is a cleaner fuel.

Respiration is a natural and continuous process, while burning is an artificial and discontinuous process.

Fuel + Oxygen → Heat + Light + Carbon dioxide + Water vapour

Air pollutants are harmful and unwanted substances that contaminate the air, such as sulphur dioxide, oxides of nitrogen, carbon dioxide, carbon monoxide, dust, and smoke.

Iron + Oxygen + Water → Hydrated iron oxide (rust)

Ethyl mercaptan is added to LPG to give it a strong smell, which helps to detect any gas leakage for safety reasons, as LPG itself is odorless.

Air cannot be represented by a chemical formula because its composition is not fixed and its components are not chemically bonded.

The greenhouse effect is the natural process where certain atmospheric gases trap heat, and an increase in these gases due to human activities intensifies this effect, leading to global warming, which is the increase in Earth’s average temperature.

In the rainy season, air contains more water vapour compared to the summer season, and the amount of oxygen is less on mountains compared to plains.

Animals obtain nitrogen by eating plants directly or by consuming other animals that eat plants.

Fuels are used to cook food and to run automobiles.

Methane and oxides of nitrogen are two greenhouse gases other than carbon dioxide.

When components of air are mixed, there is no change in energy, and the individual components retain their properties, unlike in compound formation.

Carbon dioxide is used to prepare fizzy soft drinks.

Carbon dioxide + Water Food (Glucose) + Oxygen

Atmospheric nitrogen becomes available to plants through nitrogen fixation, where it is converted into nitrates by natural lightning or by nitrogen-fixing bacteria in the root nodules of leguminous plants.

Tall chimneys with filters should be installed in factories to make smoke and gases go high up in the air while also removing harmful pollutants before they are released.

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