Solid sodium metal reacts with liquid water to produce aqueous sodium hydroxide and hydrogen gas as shown by the chemical equation: 2 Na(s) +2H2O(I) —> 2 NaOH(aq) +H2(g)

How many grams of water are used in this reaction to form 4.0 g or hydrogen gas?

A) 36 g

B) 72 g

C) 80 g

D) 8 g

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.