Question

aluminum reacts with excess aqueous hydrochloric acid to produce hydrogen.
(a) write a balanced chemical equation for the reaction, using the smallest integer coefficients possible. write states in brackets. (hint: alcl₃ is the second product.)
(b) calculate the mass of pure al that will furnish 10.3 l of hydrogen at a pressure of 0.828 atm and a temperature of 31.8°c.
use the references to access important values if needed for this question.

Explanation:

Step-by-Step Format:

Step 1: Write the balanced chemical equation

Al(s) + HCl(aq)\ →\ AlCl₃(aq) + H₂(g)
Balance the equation:
2Al(s) + 6HCl(aq)\ →\ 2AlCl₃(aq) + 3H₂(g)

Step 2: Use ideal gas LAW to Calculate the moles of H₂

The ideal gas law is \(PV = nRT\)
Where \(P = 0.828\ atm\), \(V = 10.3\ L\), \(R = 0.0821\ L\cdot atm/(mol\cdot K)\), \(T=(31.8 + 273.15)K=304.95\ K\)
Rearrange for \(n\): \(n=\frac{PV}{RT}\)
\(n=\frac{0.828\ atm\times10.3\ L}{0.0821\ L\cdot atm/(mol\cdot K)\times304.95\ K}\)
\(n=\frac{8.5284}{25.047}\approx0.3405\ mol\)

Step 3: Use stoichiometry to find moles of Al

From the balanced equation \(2Al\sim3H₂\)
Moles of \(Al=\frac{2}{3}\times\) moles of \(H₂\)
Moles of \(Al=\frac{2}{3}\times0.3405\ mol = 0.227\ mol\)

Step 4: Calculate mass of Al

Molar mass of \(Al = 26.98\ g/mol\)
Mass of \(Al=\text{moles}\times\text{molar mass}\)
Mass of \(Al=0.227\ mol\times26.98\ g/mol\approx6.12\ g\)

Answer:

(a) \(2Al(s)+6HCl(aq)
ightarrow2AlCl₃(aq) + 3H₂(g)\)
(b) \(6.12\ g\)