Matter in Our Surroundings: Important Questions

Very Short Answer Questions [1 Mark Questions]

Ques. Which of the following matters?

Chair, air, love, smell, hate, almonds, almonds, thought, cold, cold drink, perfume scent

Ans: Because matter is defined as any 'physical substance,' almonds, air, a chair, the scent of perfume, a cold drink, and fragrance can all be considered matter.

Ques. Why does the temperature of any substance remain constant during a change of state?

Ans: The temperature of a substance or matter remains constant during a change of state because all of the heat or energy delivered to particles of matter is used to separate the particles of matter.

Ques. Propose a technique for liquefying atmospheric gases.

Ans: Lowering the temperature while increasing the pressure is one way to liquefy atmospheric gases.

Ques. Why does putting acetone, fuel, or perfume on our palms feel cold?

Ans: Because perfume, petrol, and perfume are volatile liquids, they will absorb heat from our palm and cool us down if we apply them on our palms.

Ques. Why is it easier to drink hot tea or milk from a saucer than a cup?

Ans: When we use a saucer instead of a cup, the surface area available for evaporation increases, resulting in faster evaporation of tea or milk particles, allowing it to cool faster and making it easier to take a drink.

Ques. What clothing should we wear in the summer?

Ans: We must dress in clothing that allows for easy evaporation, as evaporation induces cooling. We must favour cotton clothing in the summer since it absorbs perspiration efficiently and allows for simple evaporation.

Read more: Derivations of Kinetic Energy

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Short Answer Questions [2 Marks Questions]

Ques. Explain why the following observation is true:

You can smell hot, sizzling food from several meters away, but you have to come near to smell cold food.

Ans: When the temperature is higher, the diffusion rate (movement) of particles is much faster than when the temperature is lower, and because the temperature of hot sizzling food is more elevated than cold food, the fragrance of hot sizzling food can reach us from several meters away.

Ques. In comparison to solids, liquids have a lower density. However, you must be aware that ice floats in water. Find out why this is.

Ans: Ice floats on water because there is a big empty space inside the 3D structure of ice, making it lighter than water and allowing it to float.

Ques. On a hot dry day, why does a desert cooler keep you cooler?

Ans: When hot air enters a desert cooler through the straw mates, it quickly evaporates the water because evaporation is faster on a hot, dry day. It also cools the air more quickly than on a hot, dry day because of the quicker evaporation rate.

Ques. How does water held in an earthen pot (matka) cool down during the heat?

Ans: In an earthen pot, evaporation occurs through the microscopic pores on the surface, creating a cooling effect. As a result of constant evaporation, water held in an earthen pot turns chilly during the summer.

Ques. Give a reason for the following observations.

1. Naphthalene balls vanish with time, leaving no solid behind.
2. We can detect the scent of perfume from a distance of several metres.

Ans: 

1. Sublimation is the process of converting stuff from a solid to a gaseous state without passing through a liquid state. Sublimation is a feature of naphthalene balls, which allows them to transition from solid to gaseous state without converting to liquid. As a result, naphthalene balls will evaporate over time, leaving no solid.
2. Because volatile compounds, such as perfumes, quickly transition from a liquid to a gaseous form, they can spread and combine with air particles to reach our nostrils. As a result, we detect the scent of perfume from a distance of several metres.

Ques. Why is ice at 273 K more effective than water at the same temperature in terms of cooling?

Ans: At 273 K, ice will produce a more powerful chilling effect than water because the ice will absorb latent heat of melting from the surroundings and be transformed to water. As a result, ice at 273 K is more effective than water at the same temperature in cooling.

Ques. What happens when the solids' temperature rises?

Ans: When we raise the temperature of a solid, we are providing it with energy. That energy is used to boost the kinetic energy of the particles, increasing their speed and allowing them to vibrate more freely as a result. The particles begin to move more freely once they have overcome the force of attraction between them.

Read more: Behaviour of Gas Molecules

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Long Answer Questions [3 Marks Questions]

Ques. What are the physical features of matter particles?

Ans: The qualities of matter particles are as follows:

1. Matter particles are constantly in motion.
2. The particles of matter have gaps between them.
3. Between the particles of matter, there is an attraction force that binds them together.

Ques. Give reasons:

• A gas fills completely the vessel in which it is kept.
• A solid wood table should be termed such.
• We can easily move our hand in the air, but a karate expert is required to do it through a solid block of wood.

Ans:

1. Because gas particles have a negligible attraction force between them, they flow freely in all directions, filling the entire container where the gas is housed.
2. Because gas particles move freely, they clash with container walls randomly and continuously. As a result, particle collisions against container walls impose pressure on the walls.
3. Solids have stiff and fixed particles, well-defined shapes, and well-defined boundaries. A wooden table should be labeled a solid because it has all of the features of a solid. Because air is a gas, the forces of attraction between its particles are very weak, making it easy to separate them with the aid of an external force. As a result, we can easily move our hands in the air. On the other hand, solids have strong forces of attraction, and it takes significant power to separate the particles of a solid, necessitating the use of a karate master.

Ques. Is it possible to convert between the three states of matter? How will they be able to communicate with one another?

Ans: Yes, the three states of matter are interconvertible:

1. We can turn solids into liquids and liquids into solids by heating and cooling them.
2. We can evaporate liquids to turn them into gases, and condense gases to turn them back into liquids.
3. We can transform solids into gases and vice versa using sublimation and liquids into solids using condensation.

Ques. Why do we have to get close to smell cold food, whereas the smell of hot food reaches us from several meters away?

Ans: When particles are at a high temperature, their movements are rapid, and they can traverse many meters. As a result, the scent of heated food will reach us from several meters.

Particles do not have enough kinetic energy to reach a distance of several metres at lower temperatures, hence their movements are slow. As a result, we must get close to smell the cold meal.

Read more: Heat of Fusion Formula

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Very Long Answer Questions [5 Marks Questions]

Ques. Perform an experiment to demonstrate the sublimation of ammonium chloride.

Ans. Experiment with the following to represent the sublimation of ammonium chloride (NHCl₄):

1. Place an inverted funnel and an ammonium chloride (NHCl₄) crystal in a china dish.
2. Heat the ammonium chloride (NHCl₄) crystals using a burner.
3. Vapours of ammonium chloride (NHCl₄) and ammonium chloride (NHCl₄) crystallized along the walls of the beaker's upper end can be seen when the ammonium chloride (NHCl₄) crystal is heated.
4. This experiment demonstrates that solid ammonium chloride (NHCl₄) solidifies. It does not convert to liquid, but it does shift from solid to vapour state.

Ques. What is the difference between distillation and fractional distillation? What is the fundamental difference between the two methods?

Ans: Distillation is a method of separating the components of a mixture with two liquids with different boiling points that boil without decomposition.

Fractional distillation is a method for separating the components of a combination, including more than two liquids with a boiling point difference of fewer than 25 degrees Celsius.

The fundamental difference between these two strategies is:

Only components with a considerable variation in boiling points can be separated by distillation. When the difference in boiling points is small, fraction distillation is used.

Ques. In a solid, liquid, or gas, what is the state of inter-particle distance?

Ans: Because the forces of attraction between the particles in a solid are very strong, the solid's particles will be very close to one another, and the inter-particle distance will be minimal.

Because the forces of attraction between the particles in a liquid are very weak, the liquid's particles will not be tightly packed, and the inter-particle spacing will be vast.

Because the forces of attraction between the particles in a gas are essentially non-existent or extremely weak, the particles of a gas are very loosely packed and separated from one another, and the inter-particle distance is quite large.

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