Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C.
Zn(s) + 2H⁺(aq) $\rarr$ Zn²⁺(aq) + H₂(g)

Question

Calculate the amount of work done against an atmospheric pressure of 1.00 atm when 500.0 g of zinc dissolves in excess acid at 30.0°C.
Zn(s) + 2H⁺(aq)

\rarr

Zn²⁺(aq) + H₂(g)

Quizplus · Accepted Answer

The work done can be calculated using the equation:
w = -PΔV
where P is the atmospheric pressure and ΔV is the change in volume.
In this case, the reaction involves the production of hydrogen gas, which will increase the volume of the system. Therefore, the work done will be negative.
Using the ideal gas law, we can calculate the volume of hydrogen gas produced:
n(H2) = n(Zn) = 500.0 g / 65.38 g/mol = 7.64 mol
PV = nRT
V = nRT/P = 7.64 mol x 0.0821 L·atm/mol·K x (273.15 + 30.0) K / 1.00 atm = 18.1 L
ΔV = 18.1 L
Substituting into the equation for work done:
w = -PΔV = -(1.00 atm) x (18.1 L) = -18.1 J = -18.1 x 10^-3 kJ = -19.3 kJ (to three significant figures)

Calculate the Amount of Work Done Against an Atmospheric Pressure →\rarr→

Calculate the Amount of Work Done Against an Atmospheric Pressure $\rarr$