Calculate the volume of 1.4e25 atoms of n2

In which chemical equation, which symbol should be used to indicate that substance is in solution?

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

Sulfuric acid (a component of acid rain) reacts with limestone (calcium carbonate) to produce calcium sulfate and carbon dioxide. this damages buildings and statues made of limestone. which solution of sulfuric acid will damage these structures more quickly? a. 0.001% b. 0.005% c. 0.010% d. 0.015%