TUTORIAL 3.3GAS & ATMOSPHERIC PRESSURE

1. Gas pressure exits because the gas molecules

A. move randomly and freely

B. move at the same velocity

C. collide with one another in elastic collisions and with the walls of the container in

D. collides with the wall of the container produces change of momentum

2. Which one of the following pairs of measuring instruments to measure gas pressure is true?

A. Bourdon gauge and manometer

B. Manometer and Fortin’s barometer

C. Bourdon gauge and Fortin’ barometer

D. Fortin’s barometer Fortin and Aneroid barometer

3. The figure shows a manometer used to determine pressure in a gas tank. Which comparison is correct about pressure in the gas tank with the atmospheric pressure? (2004)

A Pressure in the gas tank is equal to the atmospheric pressure

B Pressure in the gas tank is greater than the atmospheric pressure

C Pressure in the gas tank is less than the atmospheric pressure

4. The figure shows a manometer is connected to a gas supply. If the atmospheric pressure is 76 cm Hg determine the pressure of the gas.

A 30 cm Hg

B 46 cm Hg

C 76 cm Hg

D 106 cm Hg

5. We do not experience the atmospheric pressure at sea level because

A. the atmospheric is very light

B. the density of atmospheric is less than the density of our body

C. the force exerted by the atmospheric pressure is zero

D. the pressure of our body equal to the atmospheric pressure

6. The figures show a simple mercury barometer. Which one shows the height, h, to be measure to find atmospheric pressure?

7. The figure shows a mercury barometer.

What happen to the height of h if the glass tube is tilted ?

A decreases

B increases

C remains unchanged

8. Normally mercury is used in a barometer because it is

A expands uniformly

B has a higher density

C has a higher boiling point

D does not stick to the glass tube

9. The figure shows a suction pump being pressed against a smooth wall. The pump sticks to the wall when released. The pump sticks to the wall because …. (2005)

A the atmospheric pressure is equal to the pressure inside the pump

B the atmospheric pressure is less than the pressure inside the pump

C the atmospheric pressure is more than the pressure inside the pump

10. A suction pump is pulled upwards to remove dirt from a blocked sink pipe. Which diagram shows the pressures correctly? (2008)

11. The figure shows a mercury barometer What is the pressure at point X? [ The atmospheric pressure = 75 cm Hg ]

A 0 cm Hg

B 65 cm Hg

C 75cm Hg

D 85 cm Hg

E 100 cm Hg

12. The figure shows a mercury barometer.

If the vacuum space in the tube is filled with gas X , what is the pressure of gas X?

[ The atmospheric pressure = 75 cm Hg ]

A 0 cm Hg

B 20 cm Hg

C 55 cm Hg

D 75 cm Hg

E 95 cm Hg

13.Diagram below shows a simple barometer. The difference in height of the two mercury levels is h. What happens to the value of h when mercury is added to the container? (2007)

A. Increases

B. Decreases

C. No change

14. Which of the following situations only occurs due to atmospheric pressure? (2007)

15. Diagram 10 shows a manometer connected to a balloon. What is the pressure, PB, inside the balloon? (ρ = density of mercury, g = gravitational acceleration, Patm = atmospheric pressure)

A. PB = hρg

B. PB = Patm – hρg

C. PB = Patm + hρg

17. The figure shows an arrangement of apparatus is used to determine the atmospheric pressure in a laboratory. The length of the glass tube is 100 cm and the atmospheric pressure in the lab is 75 cm Hg.

(a) Name the apparatus as shown in the figure.

(b) Name the space P.Fortin / Mercury Barometer

Name the apparatus as shown in the figure.

……………………………………

(b) Name the space P.

……………………………………

Vaccuum

(c)(i) What is the value of h?

(ii)Give one reason why don’t the mercury column drops until it reaches the level of the mercury in the dish?

(d) Determine the pressure in units cm Hg at point

(i) J

(ii) K

75 cm

Support by the atmospheric pressure

75 cm Hg

75 + 15 = 90 cm Hg

What will happen to the value of h if

(i)the tube is raised through a height 10 cm

(ii) the tube is lowered through a depth of 5 cm

(ii) the glass tube is inclined about 50

from the vertical line.

(iv) the surrounding temperature increases.

• (v) the apparatus is placed on the top of a mountain.

• (vi)the space P in the tube is filled with the little of water.

No change

No change

No change

Increase

decreases

decrease

(a) Why does the pressure in a plane cabin which fly at a high altitude must be maintained at the atmospheric pressure at the sea level?

(b)What will happen if one of the plane wind screen broke suddenly? Explain your answer.

The pressure in the place cabin must equal to the pressure inside the passenger’s body which is equal to atmospheric prssure at the sea level.

Everything inside the plane cabin will go out. The pressure inside the cabin is higher than the pressure

outside.