- AMelting, energy increases.
- BEvaporation, energy decreases.
- CCondensation, energy decreases.
- DFreezing, energy increases.
The process of a gas changing into a liquid upon cooling is called condensation. During condensation, the particles lose kinetic energy, slow down, and come closer together, meaning their energy decreases.
More Questions on Particulate Nature of Matter
A student claims that when a solid melts, the particles expand in size, causing the volume to increase. Is this statement correct? Justify your answer.
→ 2At the boiling point of a liquid, what is the relationship between the vapor pressure of the liquid and the atmospheric pressure?
→ 3Which of the following scenarios would lead to the fastest rate of water evaporation?
→ 4A substance undergoes a change from state P to state Q. In state P, the particles are very far apart and move randomly. In state Q, the particles are close together but can still move past each other. What is the process from P to Q?
→ 5Why might food cook faster in a pressure cooker at sea level compared to an open pot in the mountains?
→ 6Compare the rate of diffusion in solids, liquids, and gases, providing a reason for the observed differences.
→ 7A gas is stored in a cylinder with a movable piston. If the piston is pushed down, reducing the volume, what happens to the particles of the gas inside the cylinder?
→ 8What is the theoretical temperature at which the particles of a substance are assumed to have minimum possible kinetic energy (almost zero motion)?
→ 9Distinguish between the role of heat energy when it causes a temperature rise in a substance versus when it causes a change of state at a constant temperature.
→ 10When a bottle of perfume is opened in one corner of a room, its fragrance quickly spreads throughout the room. This phenomenon is best described as:
→ 11Generally, solids are denser than liquids, and liquids are denser than gases. Explain this in terms of the particulate nature of matter.
→ 12Why does a strong wind increase the rate of evaporation?
→ 13Based on the particulate nature, how would you define 'matter'?
→ 14At a very low temperature, a substance exists as a solid. As heat is continuously added, it becomes a liquid, then a gas. Describe the change in the kinetic energy of its particles during the entire process.
→ 15State whether the following statement is true or false and provide a brief reason: "Particles of matter are only visible under a powerful microscope."
→ 16Why are solids rigid, while liquids and gases are not?
→ 17Which state of matter has the largest intermolecular spaces between its particles, and what is a direct consequence of this large spacing?
→ 18Why can you usually smell hot food from a distance much better than cold food?
→ 19How does increasing the pressure affect the boiling point of a liquid?
→ 20A substance flows easily, has particles that are loosely packed, and takes the shape of its container but maintains its volume. What is its physical state?
→ 21A substance is heated from solid to liquid, then from liquid to gas. Sketch a rough temperature-time graph for this process, indicating the regions where temperature remains constant and why.
→ 22Assertion (A): The kinetic energy of particles of matter increases with an increase in temperature. Reason (R): Higher temperature provides more energy to the particles, making them move faster.
→ 23Why does sweating help cool down our body?
→ 24If you mix 50 mL of water with 50 mL of alcohol, the total volume of the mixture is usually less than 100 mL (e.g., 98 mL). What characteristic of matter explains this observation?
→ 25Describe the arrangement of particles in a solid, liquid, and gas.
→ 26Dry ice (solid carbon dioxide) is stored under high pressure. When exposed to atmospheric pressure, it directly changes into a gas. This process is an example of:
→ 27Arrange the following in increasing order of intermolecular forces of attraction: water, oxygen, iron.
→ 28Why do clothes dry faster when spread out than when crumpled?
→ 29Which of the following substances undergoes sublimation at room temperature and atmospheric pressure?
→ 30While observing pollen grains suspended in water under a microscope, a student notices that the pollen grains are constantly moving in a zigzag path. What does this observation indicate about the nature of water particles?
→ 31A block of ice at 0°C is placed in a warm room. It takes 10 minutes for half of the ice to melt. Approximately how much longer will it take for the remaining half of the ice to melt, assuming constant heat supply from the room?
→ 32Compare the rigidity and fluidity of solids, liquids, and gases.
→ 33If a liquid has a boiling point of 100°C at atmospheric pressure, what happens to its temperature once it starts boiling vigorously?
→ 34To convert a gas into a liquid, what changes in temperature and pressure would typically be required?
→ 35When a crystal of potassium permanganate is added to a beaker of water, the purple color spreads throughout the water without stirring. This observation is strong evidence for which two characteristics of matter's particles?
→ 36A sealed container filled with air is connected to a vacuum pump. What happens to the air particles inside the container as the vacuum pump operates?
→ 37A substance has particles that are closely packed but can slide past one another. It has a definite volume but no definite shape. In which state of matter does this substance exist?
→ 38Assertion (A): Gases do not have a definite shape or volume. Reason (R): The particles in a gas have negligible kinetic energy and strong intermolecular forces.
→ 39You observe that sugar dissolves faster in hot water than in cold water. Which characteristic of matter's particles explains this phenomenon?
→ 40Why are solids generally incompressible, unlike gases?
→ 41When ice melts at 0°C, its temperature does not rise even though heat is continuously supplied. Where does this heat energy go?
→ 42On a particular day, the humidity is very high. How would this affect the rate of evaporation of water from a wet cloth?
→ 43A substance can be easily compressed and has a very weak intermolecular force of attraction between its particles. Which state of matter is this substance most likely to be?
→ 44Explain two key differences between evaporation and boiling.
→ 45Consider three substances X, Y, and Z. Substance X has a fixed shape and volume. Substance Y has a fixed volume but no fixed shape. Substance Z has no fixed shape and no fixed volume. If substance X is heated, it changes to Y, and if Y is heated further, it changes to Z. Identify the changes of state occurring.
→ 46Why does sprinkling water on the roof on a hot sunny day make the house cooler?
→ 47A student places an incense stick in one corner of a large room. After some time, the smell spreads throughout the entire room. Which characteristic of matter's particles is primarily responsible for this phenomenon?
→ 48Which of the following properties is most responsible for the high compressibility of gases compared to liquids and solids?
→ 49Why does a solid have a definite shape and volume, while a liquid has a definite volume but takes the shape of its container?
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