Question

1. choose the correct answer.

carbon dioxide is considered a ____ gas.

• greenhouse
• molecular
• pollutant
• noxious

1. choose the correct answer.

which statement is true about carbon dioxide in the air?

• it has no effect on temperature.
• too much carbon dioxide in the air can make temperatures too cool.
• burning coal, oil, and natural gas puts carbon dioxide in the air.
• only coal puts carbon dioxide into the air.

Explanation:

Question 5

Greenhouse gases are those that trap heat in the Earth's atmosphere. Carbon dioxide ($\ce{CO_2}$) is a well - known greenhouse gas. Molecular gas is a very general term and not specific to the characteristic of $\ce{CO_2}$ relevant here. While $\ce{CO_2}$ can be a pollutant in some contexts, its primary classification in terms of atmospheric impact is as a greenhouse gas. Noxious gas refers to a gas that is harmful or poisonous, and $\ce{CO_2}$ is not typically classified as noxious in the same way as gases like carbon monoxide or sulfur dioxide in terms of acute toxicity at normal atmospheric levels.

• Option 1: Carbon dioxide is a greenhouse gas, so it does affect temperature by trapping heat, so this statement is false.
• Option 2: Too much carbon dioxide in the air leads to an increase in temperature (global warming), not a cooling effect, so this statement is false.
• Option 3: Burning coal, oil, and natural gas (fossil fuels) releases carbon dioxide into the air as these fuels contain carbon and when burned, the carbon combines with oxygen to form $\ce{CO_2}$. This statement is true.
• Option 4: Many other sources (like burning oil, natural gas, and also biological processes like respiration) put carbon dioxide into the air, not just coal, so this statement is false.

Answer:

A. greenhouse

Question 6