Given that rubidium has two isotopes, 85rb and 87rb. calculate the average atomic mass of rubidium.
note that 85rb has an atomic mass of 84.912 amu and occurs at an abundance of 72.17% while 87rb has an atomic mass of 86.909 amu and occurs at an abundance of 27.83%.

Both 1,2−dihydronaphthalene and 1,4−dihydronaphthalene may be selectively hydrogenated to 1,2,3,4−tetrahydronaphthalene. one of these isomers has a heat of hydrogenation of 101 kj/mol (24.1 kcal/mol), and the heat of hydrogenation of the other is 113 kj/mol (27.1 kcal/mol). match the heat of hydrogenation with the appropriate dihydronaphthalene.

Which of the following is a compound? a.carbon b.oxygen c.hydrogen d.water

Acontainer holds 35.8 moles of gas under 10.0 atm of pressure at 70.0 c. what is the volume of the container?