The valency of both Oxygen and magnesium is 2 why

Ican determine the molar mass of an element by looking on the under the atomic mass for the element. for example the molar mass of phosphorus is 30.974 grams/mole. avogadro’s number tells me the amount of representative particles in 1 mole of any substance. this means 12.011 gram sample of carbon and a 32.0 gram sample of sulfur have the same number of atoms.

What was bohr’s contribution to the planetary model

How many moles of sulfuric acid (h2so4) are needed to react completely with 6.8 moles of lithium hydroxide (lioh)? 2lioh + h2so4 → li2so4 + 2h2o a. 3.4 mol h2so4b. 6.8 mol h2so4 c. 10.2 mol h2so4 d. 13.6 mol h2so4