States, changes, latent heat, evaporation, factors MCQs
Practice States, changes, latent heat, evaporation, factors multiple-choice questions from Matter in Our Surroundings (Class 9 Science) - tap an answer for instant feedback and a step-by-step solution. Practice the full set free on the RankByte app.
States, changes, latent heat, evaporation, factorsQuiz - Solve & Score
Q1. Which of the following correctly compares the densities of the three states of a typical substance?
- A.Solid > Liquid >> Gas, with the gas being thousands of times less dense
- B.Gas > Liquid > Solid
- C.Liquid > Solid > Gas
- D.Solid = Liquid > Gas
Answer: A. Solid > Liquid >> Gas, with the gas being thousands of times less dense
To see why, recall that Particles in a solid are most tightly packed and in a gas are very far apart, so solid > liquid >> gas in density for most substances. Water is an exception only because ice (a special solid) is less dense than liquid water. Hence the answer is A) Solid > Liquid >> Gas, with the gas being thousands of times less dense.
Q2. Which of these phenomena is best explained by the diffusion of gases?
- A.The smell of perfume opened in one corner of a closed room spreads throughout
- B.Water rises in a thin capillary tube
- C.Iron rusts in moist air
- D.Sugar dissolves in water on stirring
Answer: A. The smell of perfume opened in one corner of a closed room spreads throughout
That leaves only option A). Confirm with the chapter rule: Diffusion is the spontaneous mixing of substances due to particle motion. Perfume vapour molecules spread through air because both gases have rapidly moving, weakly-attracted particles that mix without external stirring (chemistry, chapter 'Matter in Our Surroundings'). Answer: A) The smell of perfume opened in one corner of a closed room spreads throughout.
Q3. Why is the latent heat of fusion of ice (334 J g^-1) much smaller than that of vaporisation (2260 J g^-1)?
- A.Melting only loosens the lattice while vaporisation must completely separate molecules against all attractions
- B.Ice molecules are smaller than water molecules
- C.Melting and vaporisation occur at very different molecular weights
- D.Fusion is exothermic and vaporisation is endothermic
Answer: A. Melting only loosens the lattice while vaporisation must completely separate molecules against all attractions
Quick parse - a typical chemistry numerical. The data on the table: 334 J, 2260 J. We are after the quantity the stem asks for. Pick the chapter relation that contains every given quantity and the unknown; rearrange for the unknown. Common-sense check: Fusion only disrupts the regular crystalline arrangement. Lock in option A) Melting only loosens the lattice while vaporisation must completely separate molecules against all attractions.
Master States, changes, latent heat, evaporation, factors on RankByte
Step-by-step solutions, mock tests, live ranks and streaks - free to start.
Get early access