Calculate the work, in kJ, done when 126 g of tin dissolves in excess acid at 25.0˚C and 1.00 atm. Assume Ideal Gas behavior. Sn(s) + 2 H+(aq) → Sn2+(aq) + H2(g)
I basically need to know how to find the change in volume since work=-pressure*volume change and I have pressure already. Thanks!
You don't have a balanced equation.
mols Sn = grams/atomic mass = ?
mols H2 = mols Sn
Use PV = nRT and solve for volume.
To calculate the work done, you need to find the change in volume that occurs during the reaction. In this case, you are given the pressure but not the volume change directly.
To determine the change in volume, you can make use of the Ideal Gas Law, which relates the pressure, volume, temperature, and moles of gas:
PV = nRT
Where:
P is the pressure (in atm)
V is the volume (in L)
n is the number of moles of gas
R is the ideal gas constant (0.0821 L.atm/mol.K)
T is the temperature (in Kelvin)
Since the reaction Sn(s) + 2H+(aq) → Sn2+(aq) + H2(g) involves the production of a gas (H2), you can use the stoichiometry of the balanced equation to determine the number of moles of H2 produced.
Given the mass of tin (126 g), you can convert it to moles using the molar mass of Sn (118.71 g/mol). The conversion can be done using the following equation:
moles of Sn = mass of Sn / molar mass of Sn
Once you know the number of moles of Sn, you can use the stoichiometric coefficients from the balanced equation to determine the number of moles of H2 produced. In this case, since the stoichiometric coefficient of H2 is 1, it will be equal to the number of moles of Sn.
Finally, you can substitute the number of moles into the Ideal Gas Law equation to find the change in volume. Since the initial and final pressures are the same (1.00 atm), the equation simplifies to:
V = (nRT) / P
Substituting the values you have, you can calculate the change in volume. Remember to convert temperature to Kelvin by adding 273.15.
Once you have the change in volume, you can calculate the work using the equation:
work = -pressure * volume change
The negative sign accounts for the fact that the gas is being produced, causing an expansion of the system, which corresponds to work being done on the surroundings.
Finally, make sure to convert the work in J to kJ by dividing by 1000.
I hope this explanation helps!