Question

2. (6 pts) In a reaction, 235 mL of 1.50 M HCl solution reacts completely with an excess amount of

aluminum. If the hydrogen gas is collected over water in a container with a volume of 3.60 L and at a
temperature of 25.0 °C, calculate the pressure in the container. The vapor pressure of water is 23.78
mmHg (Table 6.4, page 232).
2Al(s) + 6HCl(aq) + 3H2(g) + 2AlCl3(aq)

Answer 1

`P=1.23atm`

Step-by-step explanation:

Hello.

In this case, since the total pressure in the container includes the pressures of both hydrogen and water:

`P=P_(H_2)+P_(H_2O)`

For the reacting solution of HCl, based on the 6:3 mole ratio with hydrogen in the chemical reaction, we can next compute the yielded moles o hydrogen:

`n_(H_2)=0.235L*1.50(molHCl)/(L)*(3molH_2)/(6molHCl) =0.176molH_2`

Then, by using the ideal gas equation we compute the pressure of hydrogen for the collected 3.60 L at 25.0 °C (298.15 K):

`P_(H_2)=(n_(H_2)RT)/(V) =(0.176mol*0.082(atm*L)/(mol*K)*298.15K)/(3.60L)=1.20atm`

Finally, since the vapor pressure of water in at is 0.03129, the total pressure is then:

`P=1.20atm+0.03129atm\\\\P=1.23atm`

Best regards!