Calculate the percentage by mass of oxygen in Al2(SO4)3 (Al=27, S=32,O= 16) PLEASE SHOW FULL WORKING

Agas mixture with a total pressure of 745 mmhg contains each of the following gases at the indicated partial pressures: co2, 245 mmhg ; ar, 119 mmhg ; and o2, 163 mmhg . the mixture also contains helium gas. part a what is the partial pressure of the helium gas? phe p h e = nothing mmhg request answer part b what mass of helium gas is present in a 10.2-l sample of this mixture at 283 k ? m m = nothing g request answer

Drag each label to the correct location on the chart. classify each reaction as endothermic or exothermic.

Stage in which a typical star has completely stopped fusion