Indicate whether each structure is aromatic, nonaromatic, or antiaromatic. Compound A is imidazole, which is a 5 membered ring with two internal alkenes. A N H with lone pair is located between the two alkenes. On the ring two positions away is another nitrogen, which has one lone pair and is s p 2 hybridized. Compound B is two fused benzene rings. Compound C is a 5 membered ring with two internal alkenes. There is a C H 2 group between the two alkenes. Compound D is a 7 membered ring with three internal alkanes and a C H plus flanking two of the alkenes. Compound E is thiazole. which is a 5 membered ring with two internal alkenes. In between the alkenes is a sulfur with two lone pairs. On the ring two positions away is a nitrogen which has one lone pair and is s p 2 hybridized.

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.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

answer; 4 electrons;