Question

a white powder is stirred into water and dissolves completely. ice melts into water at room temperature. a clear solution is mixed with another, and a solid forms at the bottom. a piece of paper is torn into small pieces. a baking soda and vinegar mixture produces bubbling and fizzing. 3. argon (ar) gas is shown in image one. draw what the particles of argon would look like if they were cooled down to form a liquid. 4. match each substance with the correct particle diagram. explain your answer using evidence from the diagrams. substances: na (s) o₂ (g) n₂(g) + o₂ (g) hno₃ (l) substance: substance: substance: substance: justify: justify: justify: justify:

Explanation:

Step1: Identify physical and chemical changes

• A white powder dissolving in water is a physical change as no new substance is formed.
• Ice melting is a physical change, just a change of state.
• A clear - solution mixing to form a solid is a chemical change (precipitation).
• Tearing paper is a physical change as it's just a change in shape.
• Baking soda and vinegar reaction is a chemical change due to gas production.

Step2: Draw argon particles when cooled to liquid

• In a liquid, argon particles are closer together than in gas but can still move past each other. Draw them more closely packed than in the gas - phase image but not in a fixed lattice like a solid.

Step3: Match substances with particle diagrams

• Na(s): Sodium is a solid metal. In a solid, particles are closely packed in a regular pattern.
• O₂(g): Oxygen is a diatomic gas. Gas particles are far apart and move freely.
• N₂(g)+O₂(g): A mixture of two gases. Particles of different gases are inter - mixed and far apart.
• HNO₃(l): Nitric acid is a liquid. Liquid particles are closer together than gas particles and can move past each other.

Answer:

1. Physical change: A white powder dissolving in water, ice melting, tearing paper. Chemical change: A clear solution mixing to form a solid, baking soda and vinegar reaction.
2. Draw argon particles closer together than in gas - phase but free to move past each other.
3. Na(s): Closely - packed regular pattern diagram. O₂(g): Diagram with far - apart moving particles. N₂(g)+O₂(g): Diagram with inter - mixed far - apart particles. HNO₃(l): Diagram with closer - together particles that can move past each other.