a sample of hydrogen gas was collected over water at 21°c and 685 mmhg. The volume of the container was 7.80 l. Calculate the mass of h2(g) collected. (vapor pressure of water = 18.6 mmhg at 21°c.)
a. 0.283 g
b. 0.572 g *
c. 0.589 g
d. 7.14 g
e. 435
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