Question

Which of the following is a greenhouse gas? (a) \(\mathrm{SO}_{2}\) (b) \(\mathrm{H}_{2} \mathrm{~S}\) (c) \(\mathrm{CO}_{2}\) (d) \(\mathrm{O}_{2}\)

Short answer

\(\mathrm{CO}_{2}\) is the greenhouse gas among the choices given.

Step-by-step solution

Understanding Greenhouse Gases

Greenhouse gases are those that can absorb and emit infrared radiation, leading to the greenhouse effect, where heat is trapped in the Earth's atmosphere. This process is vital for keeping the Earth warm enough to sustain life.

Identifying Greenhouse Gases

From the provided list, we must identify the gas that is known to absorb and emit infrared radiation. We rule out gases that are not associated with the greenhouse effect.

Determining the Correct Answer

By evaluating each option, we find that \(\mathrm{CO}_{2}\) is a well-known greenhouse gas that contributes to the greenhouse effect by trapping heat in the Earth's atmosphere. The other gases listed do not have this property.

Key concepts

Infrared Radiation

Infrared radiation is a type of energy that is invisible to the human eye but can be felt as heat. It is part of the electromagnetic spectrum that lies beyond the red end of visible light. Objects emit infrared radiation as a result of thermal agitation of molecules: the warmer the object, the more infrared radiation it emits.

In the context of our atmosphere, infrared radiation is significant because it is produced by the Earth after it absorbs visible light from the sun. This radiation is what greenhouse gases target and absorb. Not all gases have this capability, which is why understanding infrared radiation is key to identifying greenhouse gases.

Greenhouse Effect

The greenhouse effect is a natural process that warms the Earth's surface. When the Earth's atmosphere captures the sun's energy, the surface is heated and in turn re-emits energy in the form of infrared radiation. Greenhouse gases in the atmosphere, such as carbon dioxide, water vapor, methane, and nitrous oxide, are able to absorb this infrared radiation, trapping the heat in the atmosphere.

This trapped heat helps to maintain the planet's temperature at a level conducive to life, preventing it from escaping too quickly into space. However, human activities, such as the burning of fossil fuels and deforestation, have increased the concentration of these gases in the atmosphere, enhancing the natural greenhouse effect, which leads to global warming and climate change.

Earth's Atmosphere

The Earth's atmosphere is a thin layer of gases surrounding our planet. It is composed of roughly 78% nitrogen, 21% oxygen, and 1% other gases including greenhouse gases. This mixture of gases is held in place by the Earth's gravity and provides us with the air we breathe, shields us from the harsh environment of space, and absorbs and emits energy in various forms.

The interaction between the Earth's atmosphere and incoming energy from the sun is complex. The atmosphere not only includes a balance of gases that support life but also plays a crucial role in our climate system. Greenhouse gases such as carbon dioxide, although only a small component of the atmosphere, have a significant impact due to their ability to absorb infrared radiation and warm the planet.