Atmospheric Pressure and Mercury Barometer

Question 1

what is atmospheric pressure

Answer 1

the pressure exerted by the environment on an object that is exposed to the atmosphere

Question 2

the pressure is due to the

Answer 2

weight of the air above the object

Question 3

atmospheric pressure varies over the earth mainly due to

Answer 3

the height above mean sea level change

Question 4

at mean sea level, atmospheric pressure is

Answer 4

approximately 100 000Pa (in test atm pressure will be stated for all questions)

Question 5

examples that demonstrate the existence of atm pressure

Answer 5

a collapsing can and Magdeburg hemispheres

Question 6

what is a collapsing can (dont memorise these, just remember what they are)

Answer 6

Collapsing can or can crusher experiment is a demonstration of an aluminium can being crushed by atmospheric pressure. Due to the low pressure inside a can as compared to the pressure outside, the pressure outside exerts a force on the can causing the can to collapse.

Question 7

Magdeburg hemispheres

Answer 7

The hemispheres are put together and the air inside them pumped out using a vacuum pump. The tap is then closed and the hemispheres disconnected from the pump. The difference in pressure between the near vacuum inside the hemispheres and the normal air pressure outside makes it very difficult to pull them apart

Question 8

two uses of atmospheric pressure

Answer 8

rubber suckers and a drinking straw

Question 9

atmospheric pressure is measured in (not in Miss’ notes so don’t really use this)

Answer 9

bars- used for things related to weather (my dude is a rapper)

Question 10

What is a mercury barometer

Answer 10

a manometer with a column of mercury that’s height varies according to the atmospheric (barometer) pressure. it is therefore a device used to measure the atmospheric pressure or altitude at any given location

Question 11

LOOK AT

Answer 11

DIAGRAM

Question 12

how does it work (long ans, no need to memorise, just understand the concept)

Answer 12

as atm pressure rises, the weight of air on the mercury of the container drives that in the tube higher up. when pressure falls, the air becomes lighter and the mercury in the container exerts less force on that in the tube. it is recorded by reading it through the tubes measurements on the side of it

Question 13

(STRAIGHT FROM MISS NOTES) according to her, pressure is measured in

Answer 13

mmHg or even cmHg (THIS IS NOT THE UNIT)

Question 14

the value is usually

Answer 14

760 mmHg

Question 15

any device that measures pressure is referred to as a

Answer 15

manometer or Pressure Gauge

Question 16

u-tube manometer

Answer 16

LOOK AT DIAGRAM

Question 17

each surface of the liquid in a u-tube manometer is

Answer 17

acted on equally by atmospheric pressure and the levels are the same

Question 18

if one side is connected to a gas supply,

Answer 18

the gas exerts a pressure on surface A and level B rises until… (DIAGRAM)

Question 19

pressure of gas=

Answer 19

atmospheric pressure+pressure due to liquid column BC

Question 20

the pressure of liquid column BC therefore

Answer 20

equals the amount by which the gas pressure exceeds atmospheric pressure

Question 21

question 1. pls look at others and we can go through in schl

Answer 21

Atmospheric pressure= 1.01x10^5Pa
=101,000Pa
g=10Nkg^-1
(slanted) p-=2.8kgm^-3
P of gas= Atm p+ hpg
=101000+2.8
=101002.8Pa