Could you explain to me why I ended up with two marks out of a possible 6 in these questions? I think that I answered them correctly but I am not sure so I would like your help so that then I may tell my instructor.

According to the equation of NA2O2 + H2O = 4NAOH + O2, how many moles of water are needed to fully react with 10 moles of sodium oxide? The balanced equation is 2Na2O2 + H2O = 4 NAOH + O2. I don't get how to start. How do you figure out the formula to use for: how many grams of water are...

Estimate the equilibrium concentration of N2(g). Consider the chemical reaction 2NH3(g)- N2(g) + 3H2(g). The equilibrium is to be established in a 1.0L container at 1,000K, where Kc = 4.0* 10^-2. Initially, 1,220 moles of NH3(g) are present.

If the column of water in the water barometer rose to a height of 38 feet, what would the atmospheric pressure be in mm Hg?