All of the following statements are true EXCEPT a. the value of q is negative in an endothermic process. b. heat flows from the system into the surroundings in an exothermic process. c. the value of q is positive when heat flows into a system from the surroundings. d. in an endothermic process heat flows from the surroundings into the system.

Option A. the value of q is negative in an endothermic process.

Explanation:

An endothermic process is a process which requires external supply of heat. The change in heat content in an endothermic process is positive because the product has more heat content than the reactant meaning the process is absorbing heat from the surroundings.

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.