Why do you think moles are important for stoichiometry?

There are 6.022 x 10^23 atoms of hg in 1 mole of hg. the number of atoms in 4.5 moles of hg can be found by multiplying 4.5 by 6.022 x 10^23 a. 2.7 x 10^24 b. 27 x 10^23 c. 2.71 x10^24 d. 27.099 x 10^23

Write and balance the chemical equation that represents the reaction of aqueous sulfuric acid with aqueous sodium hydroxide to form water and sodium sulfate. include phases.

What is the mass of naoh that would have to be added to 500 ml of a solution of 0.20 m acetic acid in order to achieve a ph of 5.0?