How much heat is produced when 4 moles N2 react?
N2+ 3H2 → 2NH3 +22 kcal

88 kcal of heat is produced by 4 moles of N₂

Explanation:

Given:

N₂ + 3H₂ → 2NH₃ +22 kcal

According to the reaction given, 1 mole of N₂ reacts with 3 moles of H₂ to release 22kcal of heat

If 4 moles of N₂ is taken then the amount of heat formed will be = 4 X 22 kcal

                                                                                                           = 88 kcal

Therefore, 88 kcal of heat is produced by 4 moles of N₂

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.