Particulate Nature of Matter — Quiz

Q1. The chapter opens by noting that pebbles, stones and sand on a riverbank were originally

• A. Sand grains that joined to form rocks in the river
• B. Pieces of cloth and wood washed down from villages
• C. Bigger rocks in the mountains that broke down due to erosion
• D. Particles that fell from the sky as meteorites

Q2. Ravi grinds a piece of chalk to a very fine powder using a mortar and pestle. Each tiny grain of the powder is

• A. A new substance produced by grinding
• B. Still a speck of chalk, made of the same substance
• C. A mixture of chalk and the mortar's material
• D. A grain of sand because chalk has dissolved

Q3. Sara puts two teaspoons of sugar in a glass of water without stirring and tastes the top layer — it tastes plain. She then stirs and tastes the top again. Now it is sweet because

• A. Sugar particles broke into constituent particles and spread throughout the water
• B. Sugar always rises to the top whether stirred or not
• C. Stirring chemically changes sugar into a new sweet substance
• D. The water particles disappear and only sugar remains

Q4. Why do iron, water and air exist in three different physical states under ordinary conditions?

• A. Because iron is heaviest, water is medium and air is lightest
• B. Because iron is older than water and water is older than air
• C. Because the strength of interparticle attractions differs in each
• D. Because all matter actually exists as a gas underneath

Q5. In the solid state, the constituent particles can

• A. Move freely from one place to another
• B. Only vibrate or oscillate about fixed positions
• C. Float far apart with no contact
• D. Move past each other slowly

Q6. From Table 7.1, urea melts at 133 °C while iron melts at 1538 °C. Which statement best explains this difference?

• A. Urea has much weaker interparticle attractions than iron
• B. Urea is found in liquid state at room temperature
• C. Iron is hollow inside whereas urea is solid
• D. Urea contains air whereas iron does not

Q7. Generally liquid particles sit slightly farther apart than solid particles. The chapter notes an important exception

• A. Mercury — its solid particles are farther apart than liquid particles
• B. Iron — its molten state has closer particles than solid iron
• C. Ice — its particles are farther apart than those in liquid water
• D. Glass — it is a liquid disguised as a solid

Q8. In Activity 7.4, 200 mL of water is poured from container A to B and then to C. The water in each container takes the container's shape, but the volume reading at each step is

• A. Different in each container, depending on shape
• B. 200 mL in every container (no change in volume)
• C. Twice the original on each transfer
• D. Reduced to half on each transfer

Q9. Which of the following best distinguishes evaporation from boiling, as described in the chapter?

• A. Evaporation occurs only at the boiling point; boiling at all temperatures
• B. Evaporation occurs throughout the liquid; boiling only at the surface
• C. Evaporation occurs at all temperatures and only at the surface; boiling occurs at the boiling point both at the surface and inside the liquid
• D. Evaporation and boiling are exactly the same process at any temperature

Q10. In Activity 7.5, smoke from a burning incense stick is trapped in Gas Jar A. When Gas Jar B is placed over A and the glass plate is removed, the smoke is seen to

• A. Fill the entire space of Gas Jar B and Gas Jar A together
• B. Stay only in Gas Jar A as a thick layer at the bottom
• C. Settle as a black powder on the glass plate
• D. Disappear instantly into the air outside

Q11. In Activity 7.7, marks A (water alone), B (after adding sugar before stirring) and C (after sugar has fully dissolved) are made on a glass vessel. The expected order of water levels is

• A. B is highest, then C, then A is lowest
• B. B is highest, then A, then C is lowest
• C. A is highest, then B, then C is lowest
• D. All three marks are at exactly the same level

Q12. About the small spaces left between particles in solids, the chapter clarifies that

• A. They are filled with tiny air pockets
• B. They contain nothing at all
• C. They are filled with water vapour
• D. They are filled with other solid dust

Q13. Three tumblers contain hot water, room-temperature water and ice-cold water. A grain of potassium permanganate is dropped in each. The pink colour will spread

• A. Fastest in ice-cold water, slowest in hot water
• B. Equally fast in all three because amount of KMnO4 is the same
• C. Fastest in hot water and slowest in ice-cold water
• D. Only in the room-temperature tumbler

Q14. The 'Ever heard of...' box explains that soap helps remove oil stains because

• A. Soap heats the oil and turns it into vapour
• B. One end of a soap particle attaches to oil and the other mixes with water, lifting the oil off
• C. Soap kills the oil particles like a germ
• D. Soap is acidic and breaks oil into hydrogen and oxygen

Q15. Exercise 4 asks: why do gases mix easily while solids do not? The best reason from the chapter is

• A. Gas particles are free to move with large interparticle spaces and negligible attraction; solid particles are fixed in place with very strong attraction
• B. Gases are heavier than solids and so push through one another easily
• C. Solids contain salt which prevents mixing with anything
• D. Gases are alive whereas solids are non-living