Question

an object has a variable volume and shape before it changes state. after the change, it can still change in shape but has a fixed volume. which change of state has occurred?

a. solid to liquid

b. liquid to gas

c. gas to liquid

d. gas to plasma

Explanation:

1. Recall the properties of states of matter:

• Gases have variable volume and shape.
• Liquids have a fixed volume but can change shape (take the shape of their container).
• Solids have fixed volume and shape.
• Plasma is a highly ionized gas - like state with variable volume/shape.

1. Analyze the change: Before the change, the object has variable volume and shape (so it's a gas). After the change, it has a fixed volume but can change shape (so it's a liquid). So the change is gas to liquid (condensation).

• Option A: Solid to liquid (melting) - solids have fixed volume/shape, liquids have fixed volume/variable shape. But the initial state here is not solid, so A is wrong.
• Option B: Liquid to gas (vaporization) - liquids have fixed volume/variable shape, gases have variable volume/shape. The final state here is not gas, so B is wrong.
• Option C: Gas to liquid - matches the analysis (gas: variable V/S; liquid: fixed V, variable S).
• Option D: Gas to plasma - plasma still has variable volume/shape, so D is wrong.

Answer:

C. Gas to liquid