CHEM 1E03 Midterm: Ch. 7 (section 4) Notes and Equations - Energy and Thermal Chemistry

Indicate the answer choice that best completes the statement or anwers the qucation 1. Which one of the following statements is INCORRECT? Energy is neither created nor destroyed in chemical reactions b. Kinctic energy is the energy that results from an object's position. transfer heat from the system into the surroundings d. Increasing the thermal energy of a gas increases the motion of e. Energy is the capacity to do work 2. When I mole of Fe-O,(s) reacts with H() to form F energy are absorbed. Fe20 (s) + 3H2(g) → 2 Fe(s) + 3H20 g) ls the reaction endothermic or exothermic, and which of the enth

1. System vs. Surroundings a. How do you define a system? How do you define the surroundings? b. Describe the difference between the surroundings doing work ON the system and work being done by the surroundings c. How do you know when the system is doing work vs when the surroundings are doing work? d. Is heat flow negative or positive when the system does work on the surroundings? Is this endothermic or exothermic? e. Nitrogen gas is commonly compressed in cylinders for easy storage and use. If the gas is compressed to fit the volume of a 20L cylinder, and the work done on the cylinder is 2980 kJ, what is the pressure, in atm, of this compressed gas? f. Is this system open, closed, or isolated? 2. First Law of Thermodynamics a. What is it? Why is it so useful? b. How does it differ from w =-PAV? c. How do l identify a state function? d. Internal energy results from the sum of heat and work. Suppose the heat is released to the surroundings, and the work is done by this system. Write the signs of each term, and predict if the overall sign for internal energy will be positive or negative. What does this tell us about this cycle? e. The internal energy of some new fuel cell engine is determined to be 9.5 x 10* kl. The fuel cell uses a certain reaction that draws energy from the surroundings in the form of heat. In this case, the heat supplied corresponds to 1388 kJ. What is the resulting work of this fuel cell?