1. Which of the following statements is true?
a chair, the smell of perfume, the air, love, hate, almonds, thought, and the taste of cold water.
1. Which of the following statements is true?
a chair, the smell of perfume, the air, love, hate, almonds, thought, and the taste of cold water.
Explanation:
Matter includes the following substances:
Chair
Air
Almonds
lemon juice
The fragrance of perfume Because there are some volatile compounds in the air that take up space and have mass, smell is taken into consideration as a matter.
2. You can smell hot, sizzling food from a few metres away, but you have to approach close to sense the smell of cold food.
2. You can smell hot, sizzling food from a few metres away, but you have to approach close to sense the smell of cold food.
Explanation:
As airborne particles are heated to greater temperatures, they gain significant kinetic energy that helps them move quickly across a distance. Hence, even at a distance of a few metres, a person can smell hot, sizzling food.
3. In a pool, a diver can simply cut through the water. What property of matter does this observation show?
3. In a pool, a diver can simply cut through the water. What property of matter does this observation show?
Explanation:
The diver may readily cut through the water in the pool due to the weak forces of attraction between water molecules. Water has this property, which makes diving easy.
4. What qualities do matter particles have?
4. What qualities do matter particles have?
Explanation:
The following are the characteristics of matter particles:
Intermolecular gaps between the particles are present (a).
(b) Particles are always moving.
(c) They are drawn to one another
(d) All matter is made up of incredibly tiny particles that are capable of existing on their own.
5. Generally speaking, liquids are less dense than solids. Yet, you must be aware that ice floats on water. Learn the reason.
5. Generally speaking, liquids are less dense than solids. Yet, you must be aware that ice floats on water. Learn the reason.
Explanation:
Since liquid particles are more free to move around, there is generally greater volume in a liquid than in a solid. On the other hand, ice has a maximum water density at 4 degrees Celsius. Ice has a lower density and is lighter than water. It floats on water as a result.
6. Which causes more serious burns, steam or boiling water?
6. Which causes more serious burns, steam or boiling water?
Explanation:
Burns from steam are really painful. This is due to the exothermic reaction's strong heat output, which compensates for the heat lost during vaporisation.
7. Why does water at the same temperature cool less effectively than ice at 273K?
7. Why does water at the same temperature cool less effectively than ice at 273K?
Explanation:
Ice will absorb heat energy, or latent heat, from the medium at 273 K, enabling it to defeat fusion and change into water. Since water does not absorb the excess heat from the medium, ice has a stronger cooling effect than water at the same temperature.
8. Provide two justifications:
(a) Water is a liquid when it's at normal temperature.
(a) At room temperature, an iron almirah is a solid.
8. Provide two justifications:
(a) Water is a liquid when it's at normal temperature.
(a) At room temperature, an iron almirah is a solid.
Explanation:
(a) Since water has a lower melting point than air and a greater boiling point (100o C), it remains a liquid at normal temperature.
Similarly,
I) A fixed mass of water occupies a fixed volume.
(ii). Water flows to fit the geometry of the container at ambient temperature since it has no set shape.
Water is therefore a liquid when it is at normal temperature.
(b) An iron almirah is a solid at room temperature because its melting and boiling temperatures are higher than those of the surrounding air. In a similar vein,
I )A stiff iron almirah with a predetermined
ii)Metals have a fairly high density
As a result, iron almirah is a solid at room temperature.
9. What is the status of water physically at -
25°C, 0°C, or 100°C?
9. What is the status of water physically at -
25°C, 0°C, or 100°C?
Explanation:
(a) The water will be liquid at 25°C (normal room temperature)
(b) Water freezes at 0 degrees Celsius, so both the solid and liquid phases can be seen.
(c) Water is at its boiling point at 100 degrees Celsius, so both its liquid and gaseous (water vapour) phases are visible.
10. Explicitly explain the following observations:
(A) Naphthalene balls vanish over time, leaving nothing substantial behind.
(b) Even from a distance of several metres, we can detect the scent of perfume.
10. Explicitly explain the following observations:
(A) Naphthalene balls vanish over time, leaving nothing substantial behind.
(b) Even from a distance of several metres, we can detect the scent of perfume.
Explanation:
(a) Naphthalene balls sublimate at room temperature, going directly from a solid to a gaseous state without going through the intermediate state, i.e. the liquid state.
(b) Air molecules have vast intermolecular gaps and travel at a faster rate. Volatile compounds found in perfumes scatter swiftly in the air and lose concentration as they travel farther. As a result, even from a distance of several metres, we can smell perfume.
11. What kind of clothing is appropriate for summer?
11. What kind of clothing is appropriate for summer?
Explanation:
Wearing light-colored cotton clothing in the summer is advised because it reflects heat and cotton fabrics have pores that absorb sweat, allowing it to evaporate and cool the skin.
12. Why can we drink hot tea or milk from a saucer more quickly than a cup?
12. Why can we drink hot tea or milk from a saucer more quickly than a cup?
Explanation:
Since a saucer has more surface area than a cup, evaporation happens more quickly. As a result, tea or milk in a saucer cools off more quickly.
13. Why does our palm feel cold after applying acetone, petrol, or perfume to it?
13. Why does our palm feel cold after applying acetone, petrol, or perfume to it?
Explanation:
As soon as they come into contact with air, volatile compounds like acetone, gasoline, and perfume evaporate. As evaporation absorbs energy from the palm, it is facilitated and has the added benefit of cooling our hands.
14. How can water stored in a matka (earthen pot) cool throughout the summer?
14. How can water stored in a matka (earthen pot) cool throughout the summer?
Explanation:
The nature of an earthen pot is permeable. These tiny pores make it easier for water to penetrate the surface of the pot and evaporate there. Water in the pot provides the energy needed for evaporation, which causes water to cool down as a result.
15. Why does it cool more effectively in the desert on a hot, dry day?
15. Why does it cool more effectively in the desert on a hot, dry day?
Explanation:
It is because better evaporation is possible on a hot, dry day when the temperature is high and the humidity is low. Better cooling effects are produced when this evaporation is at high levels.
