I'm sorry, but I don't have access to the specific details of your experiment or the information provided in "trial 2" mentioned in your question. In order to calculate the number of moles of FeSO4 • 7H2O added to the Erlenmeyer flask in trial 2, you would need to know the mass of FeSO4 • 7H2O added or have additional information about the experiment.
Please provide more context or specific data related to trial 2, such as the mass of FeSO4 • 7H2O added or any other relevant information, so that I can assist you further.