Chapter 1 Matter In Our Surrounding Short Answer Type Question And Answers
Question 1. A small quantity of a gas is let into a large evacuated chamber, then how much of the chamber gets filled with the gas?
Answer.
A small quantity of a gas is let into a large evacuated chamber
The entire chamber gets filled with the gas, because the gas molecules have very weak intermolecular forces of attraction. This permits the gas molecules to diffuse and fill up the entire chamber.
Question 2. Why do solids not diffuse into one another?
Answer.
Solids not diffuse into one another:
Solids have very little intermolecular spaces and intermolecular force of attraction between molecules of solid is very high which prevents diffusion of molecules of one solid into another solid.
Question 3. What happens when a liquid is heated?
Answer.
When a liquid is heated:
When liquid is heated, heat which is absorbed by the liquid, increases the average kinetic energy of the particles in the liquid, thus increasing its temperature.
Question 4. Why does water boil at a lower temperature at higher altitudes?
Answer.
Water boil at a lower temperature at higher altitudes:
Boiling occurs at a point where vapour pressure becomes equal to the external atmospheric pressure. At higher altitudes as atmospheric pressure is less, so less thermal energy is required to make vapour pressure equal to the atmospheric pressure.
Question 5. What is the principle used in a pressure cooker?
Answer.
principle used in a pressure cooker:
In the pressure cooker, when the pressure in the enclosed volume above the liquid reaches greater values than the atmospheric pressure, then the temperature of boiling water within the cooker gets greater than the normal boiling temperature. Hence, cooking become faster in pressure cooker.
Question 6. Why the volume of a gas increases when heated?
Answer.
Volume of a gas increases when heated:
In gases, the intermolecular forces of attraction among the molecules are weak but the kinetic energy of the molecules is high. When energy is supplied in the form of heat, the kinetic energy of the gas molecules gets further increase but as the attractive forces are weak, the gas molecules move and spread apart to occupy a greater volume.
Question 7. When a glass beaker containing water and a large crystal of potassium permanganate is kept aside for a few hours, what change do you observe after sometime?
Answer.
When a glass beaker containing water and a large crystal of potassium permanganate is kept aside for a few hours
The solution is colourless in the beginning. After a few minutes the water at the bottom of the beaker gets dark pink, while water towards the top, is light pink. After a few more minutes, the entire liquid becomes uniformly dark pink in colour.
Question 8. What is the significance of knowing the boiling point of a substance?
Answer.
Significance of knowing the boiling point of a substance:
The significance of knowing the boiling point of a substance is:
The boiling point of a liquid indicates the strength of the force of attraction between the particles of the liquid. The higher the boiling point of a liquid, the stronger is the force of attraction between the particles of that liquid.
The boiling point of the compound helps in its identification. The measurement of the boiling point of a liquid is the criterion for purity of the substance. Apure sample of water will always boil at 100°C.
Question 9. Why does ice have a lower density than water? Explain.
Answer.
Ice have a lower density than water:
Although ice is a solid, it floats on water because it has low density or less mass per unit volume when compared to water. Most of the substances are denser in their solid state, but water is different. This peculiarity of water reflects on the structure of ice.
Question 10. Give 5 examples of diffusion from our daily lives.
Answer.
5 examples of diffusion from our daily lives:
The 5 examples of diffusion from our daily lives are:
A tea bag placed in the hot water will diffuse into water.
Adding edible colors in a liquid will diffuse the color.
Stirring sugar in hot tea will help it diffuse quicker.
When cooking pasta, the water diffuses into noodles, making them bigger and moister.
If you water wilted plants, the water will diffuse into the plants, making them firmer
Question 11. Liquid nitrogen is used as a commercial refrigerant to flash freeze foods. Nitrogen boils at -196°C. What is this temperature on the Kelvin temperature scale?
Answer.
Given:
Liquid nitrogen is used as a commercial refrigerant to flash freeze foods. Nitrogen boils at -196°C.
Nitrogen boils at -196°C.
We know,
K = °C + 273
⇒ K = –196 + 273
= 77 K
On Kelvin temperature scale, Nitrogen boils at 77 K.
Question 12. What is the essential criteria for anything to be considered as matter? Which of the following cannot be considered as matter?
Coconuts, thoughts, chair, warmth, computer, almonds
Answer. It is essential to occupy space and have mass for anything to be considered as matter. Out of all, thoughts and warmth are not matter as they neither have mass nor they occupy space.
Question 13. Which characteristic of particles is responsible for the following?
- Diffusion of gases
- Rigidity of solids
- Tendency of a gas to fill up the container in which it is kept
Answer.
- Diffusion of gases takes place due to movement of particles.
- Rigidity of solids is due to negligible intermolecular spaces between the particles.
- Tendency of a gas to fill up the container in which it is kept is due to negligible intermolecular force of attraction.
Question 14. If you could magnify a coin down to the particle level, what two observations could you make about the particles?
Answer.
The two observations we could make about the particles will be:
- There is negligible intermolecular space.
- The particles are tightly packed together.
Question 15. Give an example of a substance in which ions are present.
Answer.
Salt is a substance in which ions are present.
Question 16. What is photon?
Answer.
Photon:
A photon is defined as a bundle (or quantum) of electromagnetic (or light) energy. Photons are always in motion and, in a vacuum, have a constant speed of light to all observers.
