Revolution- is the orbiting of an object around another object... so what can i put as my example of revolution?

4moles of nitrogen gas are confined to a 6.0 l vessel at 177 °c and 12.0 atm. if the vessel is allowed to expand isothermally to 36.0 l, what would be the final pressure?

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

Determine the percent sulfuric acid by mass of a 1.61 m aqueous solution of h2so4. %