Calcium fluoride: CaF₂
Ca(2+) >>> Ar (argon)
F(-) >>> Ne (neon)
Difference between Gas and Vapour:
Gas:
A thermodynamic state in which a substance exists only in one phase i.e. Gas phase. In above given examples N₂, He and CO₂ exists as gases at room temperature. These gases cannot form a solid or liquid phase along with gas phase as these states requires very low temperatures.
Vapours:
It is a thermodyanamic state in which a substance exists in more than one phase. In given options Sulfur can exist in vapor state. This is because sulfur exists in a cyclic or chain form due to catenation (self linkage property). Therefore, a lower members of S allotrops can form a vapours.
It should be noted that when Brian first sorted out his thoughts, the first thing that he thought would happen next is that he would probably be rescued that day.
It should be noted that in Chapter 5 of Hatchet, Brian wakes up in the forest and then, he realized that he was desperately thirsty.
When Brian first sorted out his thoughts, he figured this was the first day after the crash and that he would probably be rescued that day. He believed that he was going to wither up and die if he doesn't get anything that he'll drink.
Learn more about excerpts on:
brainly.com/question/21400963
