Matter in Our Surroundings
Q1. Fill in the blanks.
a. Solids have a definite shape, distinct boundaries and fixed volumes.
b. Liquids have no fixed shape but have a fixed volume.
c. The smell of perfume gradually spreads across a room due to diffusion.
d. Heat required to change the state of a substance without changing its temperature is called latent heat.
e. Kelvin is the SI unit of temperature.
f. Solid carbon dioxide is also known as dry ice.
g. The chemical name of dry ice is carbon dioxide.
h. When steam condenses to form water, heat is released.
i. The fluorescent tube and neon sign bulbs consist of plasma.
j. Evaporation of a liquid at room temperature leads to a cooling effect.
k. The phenomenon of change of a liquid into the gaseous state at any temperature below its boiling point is called Evaporation.
Q2. Which one of the following sets of phenomena would increase on raising the temperature?
(a) Diffusion, evaporation, compression of gases
(b) Evaporation, compression of gases, solubility
(c) Evaporation, diffusion, expansion of gases
(d) Evaporation, solubility, diffusion, compression of gases
Ans. (c) Evaporation, diffusion, expansion of gases
Q3. Seema visited a Natural Gas Compressing Unit and found that the gas can be liquefied under specific conditions of temperature and pressure. While sharing her experience with friends she got confused. Help her to identify the correct set of conditions.
(a) Low temperature, low pressure
(b) High temperature, low pressure
(c) Low temperature, high pressure
(d) High temperature, high pressure
Ans. (c) Low temperature, high pressure
Q4. The property to flow is unique to fluids. Which one of the following statements is correct?
(a) Only gases behave like fluids.
(b) Gases and solids behave like fluids.
(c) Gases and liquids behave like fluids.
(d) Only liquids are fluids.
Ans. (c) Gases and liquids behave like fluids.
Q5. During summer, water kept in an earthen pot becomes cool because of the phenomenon of
Ans. (d) evaporation
Q6. A few substances are arranged in the increasing order of ‘forces of attraction’ between their particles. Which one of the following represents a correct arrangement?
(a) Water, air, wind
(b) Air, sugar, oil
(c) Oxygen, water, sugar
(d) Salt, juice, air
Ans. (c) Oxygen, water, sugar
Q7. On converting 25°C, 38°C and 66°C to Kelvin scale, the correct sequence of temperature will be
(a) 298 K, 311 K and 339 K
(b) 298 K, 300 K and 338 K
(c) 273 K, 278 K and 543 K
(d) 298 K, 310 K and 338 K
Ans. (a) 298 K, 311 K and 339 K
Q8. Choose the correct statement of the following.
(a) Conversion of solid into vapours without passing through the liquid state is called vapourisation.
(b) Conversion of vapours into solid without passing through the liquid state is called sublimation.
(c) Conversion of vapours into solid without passing through the liquid state is called freezing.
(d) Conversion of solid into liquid is called sublimation.
Ans. (b) Conversion of vapours into solid without passing through the liquid state is called sublimation.
Q9. The boiling points of diethyl ether, acetone and n-butyl alcohol are 35°C, 56°C and 118°C respectively. Which one of the following correctly represents their boiling points in Kelvin scale?
(a) 306 K, 329 K, 391 K
(b) 308 K, 329 K, 392 K
(c) 308 K, 329 K, 391 K
(d) 329 K, 392 K, 308 K
Ans. (c) 308 K, 329 K, 391 K
Q10. Which condition out of the following will increase the evaporation of water?
(a) Increase in temperature of water
(b) Decrease in temperature of water
(c) Less exposed surface area of water
(d) Adding common salt to water
Ans. (a) Increase in temperature of water
Q11. ln which of the following conditions, the distance between the molecules of hydrogen gas would increase?
(i) Increasing pressure on hydrogen contained in a closed container.
(ii) Some hydrogen gas leaking out of the container.
(iii) Increasing the volume of the container of hydrogen gas.
(iv) Adding more hydrogen gas to the container without increasing the volume of the container.
(a) (i) and (iii)
(b) (i) and (iv)
(c) (ii) and (iii)
Ans. (c) (ii) and (iii)