First Law-Exercise:
Problem 1: A volume 10 m3 contains 8 kg of oxygen at a temperature of 300 K. Find the work necessary to decrease the volume to 5 m3, (a) at a constant pressure and (b) at constant temperature. (c) What is the temperature at the end of the process in (a)? (d) What is the pressure at the end of process in (b)? (e) Show both processes in the p-V plane. Problem 2: The temperature of an ideal gas at an initial pressure p1 and volume V1 is increased at constant volume until the pressure is doubled. The gas is then expanded isothermally until the pressure drops to its original value, where it is compressed at constant pressure until the volume returns to its initial value. (a) Sketch these processes in the p-V plane and in the p-T plane. (b) Compute the work in each process and the net work done in the cycle if n = 2 kmoles, p1 = 2 atm and V1 = 4 m3. Problem 3: A 735 W stirring motor is applied to a tank of water. The tank contains 25 kg of water, and the stirring action is applied for 1 hour. Assuming that the tank is perfectly insulated, calculate the change in internal energy of the water. Also calculate the rise in temperature of the water, assuming that the process occurs at constant volume and that cv for water may be taken as 4.18 kJ/kg.K. Problem 4: A 0.0283 m3 container is filled with air at 1.365 bar and 37.77oC. Calculate the final pressure in the container if 10544.82 J of heat are added. Assume ideal gas behaviour, with constant specific heats. Problem 5: Nitrogen is to be heated at constant pressure from 310.77 K to 1921.88 K. Calculate the heat transfer per mole. C p 39.65

8071 1.5 106 kJ for N 2 T T 2 kg.K

Problem 6: Air is contained in a piston-cylinder arrangement with a cross sectional area of 4 cm2 and an initial volume of 20 cm3. The air is initially at 1 atm and 20oC. Connected to the piston is a spring having a deformation constant of ks = 100 N/cm and the spring is initially undeformed. How much heat...

...Thermodynamics Exam Prep 2012
Chapter 1: Basic and IdealGas Law
1.1 State of a System
System + surroundings = Universe
Open system: can exchange matter and energy with the surroundings
Closed system: can exchange energy with the surroundings
Isolated system: cannot exchange matter or energy with the surroundings
If one knows the x/y/z position and the vx/vy/vz velocity of a particle (6 parameters) for a time point t0 it is possible to predict where the particle will be for any future time point and to determine the previous particle positions for any time point in the past.
For many particles, it is necessary to know the 6 parameters for each gas particles, therefore 6xN parameters to know the previous and past positions of all these gas particles.
Volume
Symbol: V
Units: L
1L = 10-3m3
1000mL = 1L
1000µL = 1mL
Temperature
Symbol: T
Units: K
ºC K = +273
Pressure
Symbol: P
Units: force/area 1Pa = 1 Nm-2
105 Pa = 1 Bar
101300 Pa = 101.3kPa = 1.013 Bar = 1 atm = 760mmHg = 760 Torr
*using the SI units on the left hand side will force SI units on the right hand side
Where does gas pressure come from?
Gas molecules are in constant chaotic motion which results in frequent collisions with walls. Momentum transfer tends to ‘bulge out’ the container walls.
How Can We Manage Gas Pressure?
Many pressure gauges use a spring-loaded system to...

...IdealGas Law:
The idealgas law is the equation of state of a hypothetical idealgas. It obeys Boyle's Law and Charles Law.
IdealGas Law Formula :
General Gas Equation: PV = nRT
Pressure(P) = nRT / V
Volume(V) = nRT / P
Temperature(T) = PV / nR
Moles of Gas(n) = PV / RT
where,
P = pressure,
V = volume,
n = moles ofgas,
T = temperature,
R = 8.314 J K-1 mol-1, idealgas constant.
IdealGas Law Example:
Case 1: Find the volume from the 0.250 moles gas at 200kpa and 300K temperature.
P = 200 kPa, n = 0.250 mol, T = 300K, R = 8.314 J K-1 mol-1
Step 1: Substitute the values in the below volume equation:
Volume(V) = nRT / P
= (0.250 x 8.314 x 300) / 200
= 623.55 / 200
Volume(V) = 3.12 L
This example will guide you to calculate the volume manually.
Case 2: Find the temperature from the 250ml cylinder contaning 0.50 moles gas at 153kpa.
V = 250ml -> 250 / 1000 = 0.250 L, n = 0.50 mol, P = 153 kPa, R = 8.314 J K-1 mol-1
Step 1: Substitute the values in the below temperature equation:
Temperature(T) = PV / nR
= (153 x 0.250) / (0.50 x 8.314)
= 38.25 / 4.16
Temperature(T) = 9.2 K
This example will...

...valency of magnesium
Date :29/6/2011
Lecturer :Dr Ha Sie Tiong
Title: Determination of the Valency of Magnesium
Objective
To study the quantitative relationship between the amount of reactants and products of a reaction. A known starting mass of magnesium and the measured collection of hydrogen gas will be used to determine the reaction stoichiometry and the valency of magnesium.
Introduction
Stoichiometry is a measure of relative amount of reactants to products in an experiment. In this experiment, a known mass of magnesium and volume of hydrogen gas collected is used to determine stoichiometry in this experiment.
A known mass of magnesium ribbon is mixed with hydrochloric acid to produce magnesium chloride and hydrogen gas.
Mg(s) + xHCl (l) MgClx (aq) + (x/2)H2(g)
Magnesium will be the limiting factor in this experiment, excess of hydrochloric acid will react completely with magnesium to give hydrogen gas and magnesium chloride. The yield of hydrogen gas is depend on the amount of magnesium used, thus the volume of hydrogen gas collected can be used to determine the x number.
Methodology
1. Burette is used upside down to collect hydrogen gas produced in the experiment. There’s an unknown volume between unmarked space and the tap of burette, the volume is determined by pipette 25.00cm3 of water into the vertically clamped burette
right...

...IdealGas Law Packet Name ______________________________
12.3 Date __________________ Period _______
Given: IdealGas Law =
then P = n =
V = T =
R =
1. What pressure is required to contain 0.023 moles of nitrogen gas in a 4.2 L container at a
temperature of 20.(C?
2. Oxygen gas is collected at a pressure of 123 kPa in a container which has a volume of 10.0 L. What temperature must be maintained on 0.500 moles of this gas in order to maintain this pressure? Express the temperature in degrees Celsius.
3. How many moles of chlorine gas would occupy a volume of 35.5 L at a pressure of 100.0 kPa and a temperature of 100. (C? After determining the number of moles, calculate the number of grams of chlorine (Cl2) contained in this container?
4. What is the volume of a balloon if it contains 3.2 moles of helium at a temperature of 20. (C and
standard pressure?
5. Calculate the volume which 1.00 mole of a gas occupies at STP.
6. What volume would 20.0g of CO2 occupy at a temperature of 25 (C and a pressure of 105 kPa?
7. A 23.6g sample of an unknown gas occupies a volume of 12.0 L at standard temperature and pressure. What is the molecular mass of this gas?
8....

...ENGINEERING
Lecture Outlines
2000
Ian A. Waitz
THERMODYNAMICS:
COURSE INTRODUCTION
Course Learning Objectives:
To be able to use the First Law of Thermodynamics to estimate the potential for thermomechanical energy conversion in aerospace power and propulsion systems.
Measurable outcomes (assessment method):
1) To be able to state the First Law and to define heat, work, thermal efficiency and
the difference between various forms of energy. (quiz, self-assessment, PRS)
2) To be able to identify and describe energy exchange processes (in terms of
various forms of energy, heat and work) in aerospace systems. (quiz, homework,
self-assessment, PRS)
3) To be able to explain at a level understandable by a high school senior or nontechnical person how various heat engines work (e.g. a refrigerator, an IC engine,
a jet engine). (quiz, homework, self-assessment, PRS)
4) To be able to apply the steady-flow energy equation or the First Law of
Thermodynamics to a system of thermodynamic components (heaters, coolers,
pumps, turbines, pistons, etc.) to estimate required balances of heat, work and
energy flow. (homework, quiz, self-assessment, PRS)
5) To be able to explain at a level understandable by a high school senior or nontechnical person the concepts of path dependence/independence and
reversibility/irreversibility of various thermodynamic processes, to represent these
in terms of...

...IdealGas Law Lab
1. Procedure: First, we used a balance to weigh the canister of gas, and recorded that mass as the original weight.
Then, we filled a large bucket with water and recorded the temperature. We then filled a small test tube with water at the same temperature and poured that water into a graduated cylinder to measure the original volume of water in the tube.
We then poured the water back into the test tube and placed the tube into the bucket with the opening upwards, turning the open end downwards after the tube was fully submerged beneath the surface. We then placed the canister directly below the opening of the test tube, and released the gas so that the bubbles rose into the test tube.
Next, we used a cork whose head was larger than the opening of the test tube to block off the opening (without changing the pressure inside of the tube), so that we could transport the remaining water to a graduated cylinder. When doing this, it was very important that the water level inside of the tube was equal to that of the surrounding water in the bucket, because that ensured that since the water pressure in the tube was the same as that of the surrounding water, the pressure of the gas would be the same as that of the surrounding air. Thus, we recorded the gas pressure to be the same as the pressure in the room, which was calculated to be 763.0 mmHg.
We poured the remaining...

...________________________________________
1. For each gas, record the following:
Propane Butane Methane
a Name and formula C3H8 C4H10 CH4
b Mass of 100 mL gas (g) 0.274g 0.361g 0.100g
c Molecular weight of the gas (g/mole) 44.10g/mol 58.12g/mol 16.04g/mol
d Number of moles in the 100 mL sample 0.0062mol 0.0062mol 0.0062mol
Average of all 3 gases: (0.0062+0.0062+0.0062) / 3 = 0.0062
2. To verify Avogadro's Law, calculate the average number of moles for the three gases along with the percent deviation for each gas, according to the formula:
% deviation = |(moles of gas) - (average for all gases)| / (average for all gases) * 100%
%deviation= (0.0062 -0.0062) mol / 0.0062mol *100%
% deviation= 0%
a Average number of moles in 100 mL for all three gases 0.0062moles
b % deviation for each gas All 3 the same: 0%
c Do your results confirm Avogadro's Law? Yes
4. Based on the calculated number of moles in one 1 atm of gas, how many molecules are in 1 atm of gas? (There are 6.022 x 1023 molecules/mole)
Since all 3 gases have the same number of moles I will calculate 1 formula for all 3.
0.0062mol (6.022 x 1023 molecules/mol)= 0.0373364 →3.73 x 1022 molecules for each gas are in 1atm.
5. Even though the number of molecules in 1 atm of gas at constant pressure...

...source.
Part 2: Gas Tubes
a.) I then moved to the gas tubes, starting with Helium. I placed myself at in front of the light tube & aimed the spectroscope for the center.
b.) Repeated process with the remaining gases, Ne and Hg.
Part 3: Flame Test
a.) I turned the Bunsen burner to the desirable flame.
b.) I then took the Barium sample wooden splint.
c.) By placing the soaked part in the flame I observed the color of the flame.
d.) By observing the flame with the spectroscope I obtained the wavelength of the cation.
e.) Repeated the process with the remaining metal cat ions. (calcium, copper (ii), lithium, sodium, strontium, and cobalt (ii))
f.) Followed by the unknown metals.
DATA
Part 1: White light
1.) The light source that has a continuous spectrum is the incandescent light bulb. When I observed it with the spectroscope the colors are blended as in there are no abrupt border lines.
2.) The light source that has an absorption spectrum is the fluorescent light source. This one had the same colors as the incandescent light but it had black spaces in between.
3.) Continuous spectrum consists of a continuous set of emission lines side by side, with no gaps, and appearing as a smooth transition of all colors from red to violet. As opposed to the absorption spectrum which appears as a continuous spectrum of all colors with a number of gaps or dark black lines throughout it.
4.) The absorption spectrum is produced...

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