Answer to Question #154514 in General Chemistry for Green Capellan Sotero

Question

Hydrogen gas can be produced by the reaction of hydrochloric acid with aluminum metal. How many grams of aluminum would be needed to fill-up a 250-mL container with hydrogen gas if the density of hydrogen gas is 0.84 g/L if the yield is only 75%.

Answer 1

3HCl + Al gives AlCl₃ + 1.5H₂

density = mass/volume

0.84g/L = mass/0.25L

mass = 0.84×0.25 = 0.2125g

Percentage yield = $\frac{obtained yield}{theoreticalyield}$ × 100

75 = $\frac{0.2125}{theoreticalyield}$ × 100

theoretical yield = (100×0.2125)/75 = 0.2833g

mass of aluminum required = 0.2833/1.5

= 0.1888g