Question

1. air is composed of various compounds, including 78% of nitrogen (n₂), 21% oxygen (o₂), and less than 0.1% carbon dioxide (co₂). as the syringes volume is decreased, which set of particle diagrams best represents the change in molecular state within the syringe?

Explanation:

Step1: Analyze the nature of air

Air is a mixture of gases ($N_2$, $O_2$, $CO_2$). In a mixture, the chemical identities of the components are retained. So, the particles should remain as $N_2$ (two - white circles), $O_2$ (two - gray circles), and $CO_2$ (one - black circle and two - gray circles) molecules.

Step2: Consider the effect of volume decrease

When the volume of the syringe is decreased, the number of molecules remains the same (no chemical reaction occurs, just a physical change of compression). The molecules are just closer together.

Answer:

C.