1. Units and Significant Figures(a)Reportwith appropriate accuracy the differenceof100.1–10.1(b) Report with appropriate accuracy the product of 10.1 x 100.1(c)What is STP versus NTP?Isthe difference...

1. Units and Significant Figures(a)Reportwith appropriate accuracy the differenceof100.1–10.1(b) Report with appropriate accuracy the product of 10.1 x 100.1(c)What is STP versus NTP?Isthe difference important?(d)Suppose you do an experiment to determinethe number of molesof an ideal gas by measuring its temperature and pressurein acontainer. Based on the picture, what accuracy would you becomfortable with for the pressure gauge?(e)Assume you are usingthe pressure gauge anda thermocouple witha temperature uncertainty of+/-1C;assuming ideal gashowaccurately can you report the molarvolumen/V=RT/P?


Homework_1 MAE 200P - Homework #1 1. Units and Significant Figures (a) Report with appropriate accuracy the difference of 100.1 – 10.1 (b) Report with appropriate accuracy the product of 10.1 x 100.1 (c) What is STP versus NTP? Is the difference important? (d) Suppose you do an experiment to determine the number of moles of an ideal gas by measuring its temperature and pressure in a container. Based on the picture, what accuracy would you be comfortable with for the pressure gauge? (e) Assume you are using the pressure gauge and a thermocouple with a temperature uncertainty of +/- 1C; assuming ideal gas how accurately can you report the molar volume n/V=RT/P? 2. Energy Systems In less than 1 page (including images), describe an energy system of interest. Consider its power output and estimate its size, resource input, and potential value on what time horizon? 3. State Variables (a) What is a state variable and why are they important? (b) I have a simple piston/cylinder system containing an ideal gas at initial pressure Pi that is in a constant temperature surrounding. I compress the cylinder isothermally to 1/20th its initial volume and then expand it isothermally back to its original volume. What is the final pressure? (c) Suppose I compress and expand it adiabatically, what is the difference in the final pressure then? 4. Equations of State Begin with a rigid closed cylinder with fixed 1 L volume at 50 atm pressure and 350 K temperature. Plot the pressure as a function of temperature, as the temperature falls to 200K. (a) Assume the contained fluid is 100% carbon dioxide – assume ideal gas (b) Assume the contained fluid is 100% nitrogen – assume ideal gases (c) Assume the contained fluid is 100% carbon dioxide – assume SRK equation of state (EOS) (d) Assume the contained fluid is 100% nitrogen – assume SRK EOS Comment on the results of the plot. What is the significance of the differences? 5. First Law of Thermodynamics (a) My Vitamix blender makes hot soup mechanically. The recipe is for tomato soup, and it says to combine a 28 oz can of tomatoes, ½ cup water and ½ cup cream (with some spices) and turn the blender on soup mode for about 6 minutes for piping hot soup. Calculate the average power of the blender in soup mode. (b) One energy concept is a cogeneration system of photovoltaic solar cells combined with a thermal capture of the waste heat absorbed for hot water in homes. Do a first law analysis of a 2 kWe system where the solar photovoltaics are collecting 50% of the incoming solar irradiance, and are 10% efficient in converting sunlight directly to electrical power. What is the thermal energy available? How much water can you heat? If you do not heat water, what happens to that thermal energy? (c) Show that a perfect gas undergoing an ideal adiabatic throttling process will not change temperature; then show that a real gas (use propane, as the example) will change temperature under ideal throttling. Choose the initial conditions of a typical propane canister at room temperature and its saturated pressure condition. (d) Do an estimation first law analysis of a typical hair dryer to determine how much of the power is needed for the air flow and how much for the heating. Assume 2 air speed settings and 2 heating settings. 6. Reflections – brief paragraph each (a) Comment on the notion of equilibrium in thermodynamics (b) Comment on what you consider professional engineering practice