**Chapter-18**

**Behavior of gases**

**Learning Card-1**

__Choose the correct answer:__

1. Which of the following is a correct statement of Boyle’s law

a) P/T = constant ** b) PV= constant** c) VxT= constant d) J/V = constant

2. The move meant of molecules of air from a region of higher concentration to lower concentration is called.

** a) Diffusion** b) flow c) rectification d) all the above

3. The value of absolute zero temperature is

a) O^{0 }C b) 273^{0 }C ** c) -273^{0}C** d) 273K

4. The mathematical form of Grahan’s law of Diffusions is

5. A cotton dipped in HCI and another cotton dipped in NH_{3} are kept in extremes of a glass tube closed at either ends fumes of NH4 cl is produced near

** a) HCL** c) Middle d) NH

_{3}d) All the above

__Answer the following Questions__

**1. **__Which is the matter having least density?__

Gases.

**2. **__List the main features of gases?__

1. Gases are highly compressible

2. Gases exert pressure equally in all directions.

3. Gases mix evenly in all proportions without any mechanical aid.

4. Gases are least dense than other two states of matter.

**3. **__State Charles law.__

“At constant pressure, the volume of a fixed mass of a gas is directly proportional to its absolute temperature”

Mathematically, V∝ T

V = KT (where k is proportionality constant)

**4. **__Mention any two applications of Charles law.__

1. Balloons pops out during hot summer more frequently than in winter.

2. Soda bottles may explode on exposure to heat.

**5. **__State Boyle’s law.__

“At constant temperature the volume of a given mass of dry gas is inversely proportional to its pressure”

Mathematically, V∝ 1/P

V=k x 1/P ( k is proportionality constant)

**6. **__Mention two applications of Boyle’s law?__

1. Bubbles exhaled by such a diver grows as its approaches the surface of ocean.

2. Popping of balloon when squeezed due to increase in the pressure.

**7. **__What is diffusion?__

Random movement gaseous molecules from the region of higher concentration to the region of lower concentration is known as diffusion.

**8. **__Define rate of diffusion?__

The rate of diffusion of a gas is equal to the volume of a gas diffusing per unit time.

**9. **__State Graham’s law of diffusion.__

“The rate of diffusion of a gas is inversely proportional to the square root of its density.

**10. **__What is the relation between diffusion and mass.__

The rate of diffusion inversely proportional to mass of the gas.

**Chapter-18**

**Behavior of gases**

**Learning Card-3**

__Choose the correct answer:__

1. A tightly closed tin, half filled with water heated to boiling and suddenly immersed in ice water. The result may be

** a) It squeezes** b) It explodes c) It remains unchanged d) water becomes ice

2. In the above example the squeezing is explained using

a) Avogadro law ** b) Charles's law** c) Boyle’s law d) Graham’s law

3. A candle burning donot produce any smell. A typical smell is observed for a short period when it goes off. This can be explained by using.

a) A Gay lusaac law ** b) Graham’s law** c) Charles's law d) Boyle’s law

4. The value that can fit into the gap in the table is

Pressure Pascods | Volume | |

Gas A | 1.5 x 10 | 1.2 |

Gas B | - pa | 2 |

a) 5 x 10^{5} __b) 2 x 10 ^{5}__

^{ }c) 0.9 x 10

^{5}d) 0.8 x 10

^{5 }

__Answer the following Questions:__

**1. **__Two gases A and B which can react among them selves are kept at two ends of a glass tube as shown. A is denser than B. Towards which end the rate of reaction is more? Why?__

The rate of reaction is more towards A because B diffuses more. Than A as it is less dense.

**2. **__A container of gas has a volume of 10 liters and contains gas at a pressure of 120Pa. what will be the pressure of the gas if it is allowed to escape from the container into a space of volume 3000 lt?__

V1 = 10cl

P1 = 120 Pa

V2 = 3000*l*

P2 = ?

P1V1 = P2 V2* *

120x10 = P2 x 3000

P2 = 0.4 pa

The pressure of gas reduces to 0.4 Pa

**3. **__A fixed mass of gas initially at a pressure 2Pa is allowed to expand so that its volume increases to three times its original volume what is the new pressure of the gas.__

P1 = 2Pa

V2 =3V1

P2 = ?

P1 V1 = P2 V2

2 V1 = 3V1 x P2

P2 =0.66 pa

**4. **__The diagram shows some buddles rising in a glass of fizzy drink. Why the bubbles get larger as they rise to the surface?__

As the bubbles rises, the presure decreases hence volume increases.

**5. **__A blown balloon is kept inisde a jar which is connected to vacuum pump. What happens to the size of ballown, if air is sucked out of the bell jar?__

Balloon swells in its size due to decrease in pressure.

**6. **__A balloon is filled with 25l of air at 1 pa pressure. If the pressure is charged to 1.5 pa, what is the new volume?__

V1 = 25*l *

P1 = 1Pa

P2 = 1.5 Pa

V2 = ?

P1V1 = P2 V2

1 x 25 = 1.5 x V2

V2 = 16.66 l

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