Before proceeding, we should write the reaction equation to better understand what is happening:
2AgNO₃ + Na₂S → Ag₂S + 2NaNO₃
Now, we may apply the law of conservation of mass, due to which the total mass before a chemical reaction is equivalent to the total mass after a chemical reaction. Therefore:
Mass of silver nitrate + mass of sodium sulfide = mass of silver sulfide + mass of sodium nitrate
Mass of silver nitrate + 156.2 = 595.8 + 340
Mass of silver nitrate = 779.6 grams
The answer is 2.7gm/cm^3 . Density is mass divided by volume .
If you’re talking about noble gases, the answer would be A. Since noble gases already have 8 electrons, they don’t tend to form chemical bonds. And elements need just 8 electrons on there shells to be stable.
It is called a cycle because it is repetitive, therefore making it a cycle (or almost never ending)