Aluminum reacts with excess hydrochloric acid to form

Solution 47P

Here we have to calculate how many grams of aluminum reacted.

Step 1

The balanced chemical equation for the reaction between aluminium with HCl  to form aqueous aluminum chloride and hydrogen gas is given below,

2Al (s)+ 6HCl (g) → 2AlCl3 (aq) + 3H2(g) 

Volume of hydrogen = 35.8 mL

Temperature = 27 oC = 273 + 27 = 300 K

Pressure = 751 mm Hg

Here it has been given that hydrogen gas has been collected over water, so the partial pressure of water must be subtracted.

Pressure at 26oC is 25.2 torr and 28oC is 28.3 torr, so we will take the average of the two values to obtain the partial pressure of water at 27oC.

Hence Hydrogen pressure = total pressure - pressure of water vapour

                               = (751 mm Hg) - [(28.3 + 25.2)/2]

                               = 724.25 torr

Now by using ideal gas equation we can calculate the moles of hydrogen,

PV = nRT

n =

= 0.00138 mol H2