Which of these statements describes the basic idea of the Valence Shell Electron Pair Repulsion (VSEPR) theory? a) Shared and unshared electron pairs repel each other as much as possible.
b) There is always an octet of electrons around an atom in a molecule.
c) Electrons are attracted to the nucleus of the central atom.
d) Molecules repel one another due to intermolecular forces.

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.

the pseudoscience are like beliefs, theories, or like practices that are considered scientific

yes the answer is total mass in unchanged   : )