How do I calculate the partial pressure of HCl?

Calculate the work done if 27g of Fe reacts with excess hydrochloric acid in a closed vessel at 19C?

• When iron dissolves in 1.00 M aqueous HCl, the products are FeCl2(aq) and hydrogen gas. Calculate the work done if 27g of Fe reacts with excess hydrochloric acid in a closed vessel at 19C? How much work is done if the reaction takes place in an open vessel with an external pressure of 1 atm?

• Answer:

  part A: remember that w = -P(ext) * deltaV meaning that for WORK to occur, there needs to be movement -- ie, a change in volume. in a CLOSED VESSEL, THERE CAN BE NO MOVEMENT therefore, deltaV = 0, and the equation above becomes w = -P(ext) * 0 w = 0 J part B: 1) write the balanced chemical reaction 2) determine how many moles are in the given quantity of Fe by dividing by the molar mass. 3) From the stoichiometry of the reaction, find that 1mol of Fe is consumed and 1 mol of H2 is produced. 4) we know from the question that the reaction occurs under 1 atm pressure. All we need to do is calculate the kelvin value for the temperature and sub into PV=nRT, where P=1 atm, V=?, n=found above, R=0.0821, T=273.15+celcius degrees. 5) We know that we start with 0 moles of H2, so the change in volume, deltaV, is V (found above) minus 0. Remember that your answer will be in L*atm = 101.3J. 6) Since w = -P(ext)*deltaV, this equation becomes w = -1*deltaV*[L*atm] (deltaV caclulated using ideal gas law above) w = -1*deltaV*[101.3J] which is your final answer if you sub in the volume from the ideal gas law. I hope you learned something from this! p.s. give me thumbs up/best answer for this!