- (20 points) A container of liquid salt bath is used as a calorimeter to determine the enthalpy of formation of FeSi. It has been determined by experiment that the heat capacity of the bath is 5000J/K at 600° With the bath originally at 600°C, the following experiments are performed.
- A mixture of 0.1 mole of pure Fe and 0.1 mole of pure Si at 25°C is dropped into the calorimeter. When the mixture has dissolved completely, the temperature of the bath is found to have increased 0.275°C from 600°C.
- 0.1 mole of formula of FeSi (0.2 mole of atoms) at 25°C is dropped into the calorimeter. When the compound is dissolved completely, the temperature of the bath decreases by 1.295°C from 600°C.
Answer the following questions
- Calculate the weights of pure Fe, pure Si, and the compound FeSi from their moles used in the experiments. (2 points)
- What are the enthalpies of formation of FeSi in per moles of formula and per mole of atoms, respectively? (9 points)
- To what temperature does the result of the enthalpy of formation apply? Explain. (9 points)
Don't use plagiarized sources. Get Your Custom Essay on
- (A bonus problem, 5 points) Define the first-order and second-order phase transformations.