Sodium reacts with oxygen to produce sodium oxide. 4Na(s) + O2(g) - - 2Na2O(s)
a. How many grams of Na20 are produced when 57.5 g of Na
reacts ?
b. If you have 18.0 g of Na, how many grams of O2 are
required for reaction?
c. How many grams of O2 are needed in a reaction that
produces 75.0 g of Na2O?

Phosphoric acid is a triprotic acid ( =6.9×10−3 , =6.2×10−8 , and =4.8×10−13 ). to find the ph of a buffer composed of h2po−4(aq) and hpo2−4(aq) , which p value should be used in the henderson–hasselbalch equation? p k a1 = 2.16 p k a2 = 7.21 p k a3 = 12.32 calculate the ph of a buffer solution obtained by dissolving 18.0 18.0 g of kh2po4(s) kh 2 po 4 ( s ) and 33.0 33.0 g of na2hpo4(s) na 2 hpo 4 ( s ) in water and then diluting to 1.00 l.