Supplemental Instruction
Iowa State University / Leader: / James
Course: / ChE 160
Instructor: / Heinen/ Stiehl/ Brenza
Where: Look at your lecture notes. Honestly, your lecture notes will provide more info than the book. Or you could look up the ChE 210 book if you want extra information.
Discussion
Along with material balances, this is where most of your Chemical Engineering academic career will be spent. Chemical Engineers are known especially for their skill in thermodynamics. The basics are really, really important to understand if you don’t want to feel totally lost in ChE 381 and Chem 325 (both required in our curriculum).
Concept Questions
What is the general energy balance equation?
What does each term in the energy balance equation stand for?
Where would pump work fit into the energy balance equation?
What is enthalpy? What information does it give us? How do we measure enthalpy?
Review
The internal energy of a system decreases by 200 J while 320 J of work is done by the system. Is heat added or removed?
A dad pulls his kids in a wagon for 25 minutes on a level sidewalk. He pulls with an average force of 35 lbf at an angle of 45 to the sidewalk.
A. How much work is done? (hint: units in ft-lbf)
B. What horsepower would be required for the same work?
An SUV weighs 2400 kg and has kinetic energy of 815 kilojoules. Determine its speed in miles per hour.
A vial of water is heated from 10 °C to 20 °C by the addition of 5.0x103 BTU of energy.
A. What is the final form of this energy?
B. Express this final form in Megajoules.
A cliff diver who weighs 165 lb dives from a 135 ft cliff into the bay.
A. What is the diver’s total energy (in Joules) at 100 ft from the edge of the cliff?
B. Why might this number be inaccurate (what are we assuming)?
Write the simplified energy balance equation for the following:
A. A combustion chamber with a cylinder at the top is filled with 02 gas. The O2 is heated, and the cylinder rises
B. An endothermic reaction takes place in a closed, well-insulated container
C. An exothermic reaction takes place in a steady-state oven with a moving conveyor
Exam Prep
The best exam prep is to find questions from physics problems, and write energy balances.