Question

1. air is composed of various compounds, including 78% of nitrogen $(n_{2})$, 21% oxygen $(o_{2})$, and less than 0.1% carbon dioxide $(co_{2})$. as the syringes volume is decreased, which set of particle diagrams best represents the change in molecular state within the syringe?

Explanation:

Step1: Understand the nature of gas compression

When the volume of a syringe (containing gas) is decreased, the number of gas molecules remains the same. The molecules get closer together. The composition of air (78% \(N_2\), 21% \(O_2\), <0.1% \(CO_2\)) should be maintained in terms of the ratio of different types of molecules.

Step2: Analyze each option

• Option A: The ratio of different molecules (nitrogen - white, oxygen - light gray, carbon dioxide - dark gray) is maintained and the molecules are closer together after the volume decrease.
• Option B: The ratio of molecules changes (for example, the proportion of carbon dioxide seems to increase relatively), which is incorrect as compression does not change the composition of the gas mixture.
• Option C: The ratio of molecules changes (for example, the proportion of oxygen seems to increase relatively), which is incorrect as compression does not change the composition of the gas mixture.
• Option D: The ratio of molecules changes (for example, the proportion of nitrogen seems to decrease relatively), which is incorrect as compression does not change the composition of the gas mixture.

Answer:

A