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Energetics and Thermodynamics

Entropy and Heat

Question #1 In your own words, define entropy. Provide one everyday example resulting in an increase in entropy, and another resulting in a decrease. Question #2 About 38% of the food energy we consume is converted to chemical energy in the form of ATP, what happens to the remainder of the energy? Question #3 When w

Calculate Work Done by Reaction: Example Problem

Calculate the work done in joules by the reaction when 0.23 g of Na reacts with water to form hydrogen gas at 3°C and 2.0 atm. 2 Na(s) + 2 H2O(l)--> 2 NaOH(aq) + H2(g) I think it should be a negative number and I have tried -46J and -23J.

Thermodynamics for Work Done on Frozen Water

Calculate the work done (in joules) when 3.0 mole of water is frozen at 0°C and 1.0 atm. The volumes of three moles of water and ice at 0°C are 0.0540 L and 0.0588 L, respectively. I tried 3960J but i am way off. Where am I going wrong?

Calculate Expansion Work: Example Problem

A 15.8 g quantity of dry ice (solid carbon dioxide) is allowed to sublime (evaporate) in an apparatus like the one shown in Figure 6.5. Calculate the expansion work done against a constant external pressure of 0.959 atm and at a constant temperature of 26°C. Assume that the initial volume of dry ice is negligible and that CO2 b

Energy and work done

A 47 kg person drinks 390. g of milk, which has a "caloric" value of approximately 3.0 kJ/g. If only 18% of the energy in milk is converted to mechanical work, how high (in meters) can the person climb based on this energy intake? [Hint: The work done in ascending is given by mgh, where m is the mass (in kilograms), g the gravit

Calculating Delta E formation

What is Delta E for the formation of 8 mole of CO at 1 atm and 25°C? C(graphite) + 1/2 O2(g)--> CO(g) ΔH = -110.5 kJ/mol I am confused I tried -1552 and -112... I think i am close but seem to be off somewhere.

Work done by Sn

Calculate the work done when 50.0 g of tin are dissolved in excess acid at 1.00 atm and 24°C. Assume ideal gas behavior. Sn(s) + 2 H+(aq)--> Sn2+(aq) + H2(g) I cant find the ideal gas behavior equation/law.. i thought it might be 42J but this is incorrect.

The Freeze Dried Coffee Process

Freeze-dried coffee is prepared by freezing brewed coffee and then removing the ice component with a vacuum pump. Describe the phase changes taking place during these processes. This needs to be 200-300 words.

Ke for Equilibrium Concentrations

1, Calculate Ke for the following (equilibrium concentrations given below substances) a) H2 (g) + Br2 (g) ↔ 2 HBr (g) + heat [0.513] [0.62] [0.346] Ke = (0.346)^2/(0.513)(0.62) = 0.376 b) N2O4 (g) + heat ↔ 2 NO2 (g) [0.0325] [0.022] Ke = [NO2]^2/[N2O4]

Thermodynamic of cyclic process of an ideal gas

An ideal gas described by T(initial)=300K,P(initial)=1 bar and V(i)=10 L is heated at constant volume until P=10 bar.It then undergoes a reversible isothermal expansion until P=1bar.It is then restored to its original state by the extraction of heat at constant pressure. Calculate w for each step.

Review Questions for a Chemistry Final

I'm reviewing for my chemistry final and need stuff explained. Please give very in-depth explanations and answers so I can understand how to do it. Thank you! Determine the amount of heat (in kJ) given off when 1.26x10^4g of N02 are produced according to the equation; 2NO(g)+O2(g)---->2NO2(g) Change of heat=-114.6 kJmol

Entropy and Evolution

I am having a difficult time finding the answer to the following question. The second law of thermodynamics is often cited as a reason that biological evolution is not possibe. What types of assumptions lead to this conclusion? Most of the information I have found states the same thing i,e Henry Morris states that the m

Draw Lewis Structures and Balancing Equations: Example Problem

I need to be able to draw the Lewis structures of the following: Alcohol Ketone Peptide linkage Amine Aldehyde Balance the equation and determine the triangle H for the burning of C2H6 and O2. C-H=99 kcal C=O=192 O-O=119 kcal O-H=111 kcal C-C=83 kcal Triangle H = Balanced

Aqueous Equilibria and Chemical Thermodynamics

1. Calculate the pH of a) A solution that is 0.160 M in sodium formate(NaCHO2) and 0.260 M in formic acid(HCHO2). b) A solution that is 0.210 M in pyridine(C5H5N) and 0.350 M in pyridinium chloride(C5H5NHCl). c) A solution that is made by combining 125mL of 0.050 M hydrofluoric acid with 50.0mL of 0.10 M sodium fluoride. 2

Find enthalpy and entropy for unfolding of a protein

The following data is obtained from a study of the thermal denaturation (unfolding) of a protein: folded↔unfolded T (oC) %Unfolded 66oC 18.0 78.5oC 89.6 a. What are the values of ∆Ho and ∆So for the denaturation

Gibbs Free Energy of Reaction

The standard Gibbs free energy of formation of NH3(g) is given by ∆Gfo=-16.5 kj/mol-1 at T=298K. What is the Gibbs free energy (∆G) for the reaction: N2(g) + 3H2 ↔ 2NH3(g) when the partial pressures are: PN2=3.0 bar; PH2=1.0 bar; and PNH3=4.0 bar?

Understanding Thermodynamics and Electrochemistry

1. If the equilibrium constant for a two-electron redox reaction at 298 is 1.0×10−4, calculate the corresponding and under standard conditions. 2. A cell has a standard emf of 0.104 at 298 . What is the value of the equilibrium constant for the cell reaction if ? 3. A voltaic cell utilizes the following reaction

Finding Molar Mass Through Dumas Method

We are trying to determine the molar mass of an unknown liquid through Dumas Method: measure density (mass/volume) of its vapor at a known temperature and pressure. I am having trouble answering question 3 and question 4 as attached. 1) I did the calculations for question 3 but am really lost on whether I plugged in the r

Finding normal boiling point and enthalpy of vaporization

The vapor pressure for chlorotrifluoroethylene is in the table below. Determine the normal boiling point and the enthalpy of vaporization and compare to literature values. Temp (oC) Vapor Pressure (Pa) -146 1 -134 10 -119 100 -99 1000 -71 10000 -28.4

Determining Price of Ethanol: Example Problem

I am having trouble determining what I should do in this problem. I believe I start by figuring out the combustion reactions for ethanol and octane. For ethanol I have: C2H5OH(l)+ 3O2(g) = 2CO2(g) + 3H20(l) For octane I have: C8H18(g) + 25/2 O2(g) = 8CO2(g) + 9H20 I am lost on what to do next or what I should do with t

Enthalpy / entropy / free energy

Calculate the standard reaction enthalpy, entropy and free energy at 298K for the following reactions: a) CH3OH(l) + O2 (g) → CO2 (g) + H2O(l) b) P(s,white) + O2 (g) → P4O10 (s) c) sucrose + H2O (l) → α glucose + β fructose

Heat and Thermodynamics: Change in Enthalpy and Entropy

Calculate δH and δStotal when two iron blocks each with mass of 1.00kg, one at 25'C and one at 250'C are placed in contact with each other in an isolated container. The specific heat capacity of iron is 0.449 J/'C*gram and can be assumed to be constant over this temperature range.

Gases and Equilibria

1) Consider the following reaction at 1600°C: Br2(g) &#8660; 2Br(g) When 1.05 moles of Br2 are put in a 0.980-L flask, 1.2 percent of the Br2 undergoes dissociation. Calculate the equilibrium constant for Kc for the reaction. 2) Consider the heterogeneous equilibrium process: C (s) + CO2 (g) <---> 2CO (g) At 700

Thermodynamics and pH

Please see the attached file for the fully formatted problems. 1) A quantity of 7.480g of an organic compound is dissolved in water to make 300.0 mL of solution. The solution has an osmotic pressure of 1.43 atm at 27 degrees Celsius. The analysis of this compound shows that it contains 41.8 percent C, 4.7 percent H, 37.3 pe

LeChatelier's Principle and Endothermic Processes

If we remove CO2 from the following equation CO + H2O + heat &#61663;> CO2 +H2 Which way will the equilibrium shift? As NH4NO3 dissolves in water, the resulting solution becomes colder. Which of the following expressions is most correct? A- NH4NO3 &#61664;NH + NO + heat B- Heat + NH4NO3&#61664;NH + NO C- NH4NO3 &#61664;

Osmotic Pressure and Endothermic Processes.

What is the osmotic pressure of a 0.050 M solution of AlCl3 in water that is at 0.00C? Consider AlCl3 to be a strong electrolyte. A- 8.5 * 102 torr B- 1.1 atm C- 2.2 atm D- 3.4 * 103 torr As NH4NO3 dissolves in water, the resulting solution becomes colder. Which of the following expressions is most correct? A- NH4NO3

Fuel Efficiency : Octane versus Ethanol

If we use octane (C8 H18 ) as the representative of what is contained in gasoline, and compare it to ethanol (C2H5OH), currently a promising substitute for gasoline, what will be the energy difference on a per gram basis for the two? For the reaction of octane with oxygen to produce carbon dioxide and gaseous water, 48.1 kJ of h

Chemical Thermodynamics : Enthalpy, Entropy and Gibbs Free Energy

Consider acetic acid, CH3COOH, The active ingredient in vinegar. It is also responsible for the sour taste of wine when gets exposed to air. Bacterial oxidation turns alcohol to acid. C2H5OH (aq) +O2 &#8594; CH3COOH (aq) +H2O The following data may be useful: C2H5OH (aq): &#8710;H&#730;f = -288.3 kJ/mol