Timed Assignment: Particulate Model of Matter

Which of the following statements describe Brownian motion?

• A I and II only

• II A student carrying a table from classroom to the canteen

• I Pollen grains moving while suspended in water

• III Dust particles ‘dancing’ in a beam of light.

• IV Food dye moving in a beaker of water

When 50 cm³ of liquid X is mixed with 100 cm³ of water, the volume of the mixture is found to be 145 cm³. Assuming no evaporation has taken place, which of the following best explains the above observation?

• Liquid X and water react to form 5 cm³ of gas, which escapes into the atmosphere

• Liquid X and water react to form some solid particles

• Some particles of liquid X escape as a gas into the atmosphere

• The particles of liquid X occupy the spaces between the water molecules

Which of the following statements about liquid is not true?

• Liquid particles are held together by strong forces of attraction, and slide past one another.

• Liquid cannot be compressed, so they have a definite volume.

• Liquid has a higher density than solid.

• Liquid do not have a definite shape.

What happens to the molecules when steam condenses to water at room temperature?

• Molecules lose energy.

• Molecules become smaller.

• Molecules become regularly arranged.

• Molecules move further apart.

Three beakers labelled I, II and III, were each filled with water. The temperature of the water was set at 25°C, 50°C and 95°C. Rank the speed of diffusion of the dye throughout the water from slowest to fastest.

• A. 2 > 1 > 3

• B. 3 > 2 > 1

• C. 1 > 3 > 2

• D. 1 > 2 > 3

Some processes bring about a change in the state of matter. Which of the following processes take in energy and give out energy respectively?

• (i) Melting, (ii) Freezing

• (i) Condensation, (ii) Evaporation

• (i) Sublimation, (ii) Deposition

• (i) Freezing, (ii) Melting

Using the model of the particulate nature of matter, describe how a solid changes to a liquid.

• A solid changes to a liquid by melting, where particles gain energy and move more freely.

• A solid changes to a liquid by freezing, where particles lose energy and become fixed.

• A solid changes to a liquid by condensation, where particles lose energy and come closer together.

• A solid changes to a liquid by sublimation, where particles gain energy and move directly to a gas state.

A student is conducting an experiment using the apparatus as shown. Before he heats the metal ball, the metal ball can pass through the ring easily. The student then heats the metal ball. What would happen when the student tried to place the heated metal ball through the ring?

• The heated metal ball will pass through the ring easily.

• The heated metal ball will not pass through the ring.

• The heated metal ball will shrink and pass through the ring.

• The heated metal ball will expand and pass through the ring.

Draw the model of particles for different states of matter: Solid, Liquid, Gas.

• Solid: Particles are closely packed; Liquid: Particles are loosely packed; Gas: Particles are far apart.

• Solid: Particles are far apart; Liquid: Particles are closely packed; Gas: Particles are loosely packed.

• Solid: Particles are loosely packed; Liquid: Particles are far apart; Gas: Particles are closely packed.

An air-tight container with a piston is filled with oxygen gas. A force is then applied onto the piston as shown in Fig. 3.1. Can the piston be pushed into the container if the container is filled with water? Explain your answer using your understanding of particulate model of matter.

• Yes, because water is compressible.

• No, because water is incompressible.

• Yes, because the force applied is greater than the resistance.

• No, because the piston cannot move in water.