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Energetics and Thermodynamics

Various Calculations of Thermodynamics

1. At 25 degees C, (triange)H(little o) for the combustion of liquid octane, C8H18(l) to form CO2(g) and H2O(l) is -5471kJ/mol. Calculate (triangle)E(little o) for this reaction at 25 degrees C. 2. The molar heat of vaporization of benzene, C6H6, at 1 atm is 30.8 kJ/mol. The boiling point of benzene at 1 atm is 78.3 degree C.

The gaseous hydrocarbon acetylene, C2H2 is used in welders' torches because of the large amount of heat released when acetylene burns with oxygen, producing carbon dioxide and water.

1. The gaseous hydrocarbon acetylene, C2H2 is used in welders' torches because of the large amount of heat released when acetylene burns with oxygen, producing carbon dioxide and water. First, write a balanced equation fro the combustion of acetylene is oxygen. Then, how many grams of oxygen are needed for the complete combusti

Gas-phase absolute entropy

1. Which molecule below should have the highest gas-phase absolute entropy at 25°C? a. CH4 b. H2 c. C2H6 d. C2H4 e. C2H2 2. Some standard entropies (at 25°C in J/mol K) are given: Ca2+(aq) -55.2, F-(aq) -9.6, CaF2(s) +68.87. ΔS° for the reaction CaF2(s)  Ca2+(aq) + 2F-(aq) at 25°C in J/K is ____

General Chemistry and Thermodynamics

7.5. Given the following table of thermodynamic data, substance ΔHf° S° POCl3 (g) -542.2 kJ/mol 325 J/mol - K POCl3 (l) -597.0 222 determine the normal boiling point (in °C) of POCl3. a. 133.0 b. 532 c. 273

General Chemistry - Law of thermodynamics

1. Which one of the following is a correct statement of the first law of thermodynamics? a. ΔS = q - T absolute zero, for a pure crystalline solid, S = O c. ΔS >or equal q/T d. ΔH = ΣΔHproducts - ΣHreactants e. ΔE = q + w 2. A reversible process is one that ________. a. must be carried out at high

Thermodynamics and Specific Heat

You are given 10.0 grams of a mixture of NaNO3 and KF. You dissolve this mixture in 100.0 grams of water, and the temperature rises by 1.02°C. Calculate the mass of each salt in the original mixture. Assume that the specific heat of the solution is 4.18 J/g°C. Useful information: Enthalpy of solution of NaNO3: +20.5 kJ/mol

Thermodynamics and Enthalpy of Formation

I need some help with this problem, see attached file for full problem description with proper symbols: 2. a) Use only the following data to determine delta H°f for NO2 (g): - delta H°f for NO (g) is +90.4 kJ/mol - delta H = -56.6 kJ/mol for the reaction: NO (g) + 1/2 O2 (g) ---> NO2 (g) b) Find delta H for the reaction: 4


1. I need help with the standard deviation/percentage error in the attached lab experiment. 2. Also need help graphing for the ethyl acelate and unknown solvent -- plotting negative delta T versus the total volume of solute that was added (2 graphs) and calculation of the slopes 3. I am not certain but I believe this ques

P chem

Calculate deltaS standard for the sublimation of CO2. The enthalpy of sublimation is delta H^0=25.23 kJ/mol at 195K. delta S^0= 1 ATM


1. In a free radical reaction, the following step would be categorized as CH3. + Br . ----------> CH3Br a. Initiation b. Propagation c. Substitution d. Termination 2. The heat of reaction (enthalpy change, delta H) for the following reaction is I2 + CH4 -----------> CH3I + HI a. 13 kcal/mol b. 140 kca

Vapor Density & Ideal Gas Law

Please take a look at the attached lab report on vapor density. Please see the ** items regarding percentage error and calculation of R. I can't figure out how to do the percentage error of my trials and the calculations for the R values are confusing. Thanks for your help. --- Vapor Density and the Ideal Gas Law Lab Con

Enthalpy Change and Affecting Variables

Change in (delta) H degrees = 2816kJ 6CO2(g) + 6H2O (l) <->C6H12O6(s) + 6O2 (g) How is the equilibrium yield of C6H12O6 affected by: a. Increasing P CO2 (explain) b. Increasing temperature (explain) c. Removing CO2 (explain) d. Decreasing the total pressure (explain) e. Removing part of the C6H12O6 (explain) f. Addin

Energetics and Thermodynamics - Basic Chemical Equations

1. a. Calculate the [H+] of a weak acid solution with [OH-] = 3.50x10^-8M b. Calculate the pH of the solution c. Calculate the [H+] of a Classic Coke if the pH=3.75 2. Write the balanced equations: (Neutralizations) in ionic form and show net ionic equation. a. H2SO4(aq) + NaHCO3(aq)--> b. H3PO4(aq)+Mg(OH)2--> 3. Cal

Heating Curve of solid subtance

In a heating curve of a solid substance: Which phase (curve) would represent the heat of vaporization? Which phase (curve) would represent kinetic energy? Which phase (curve) would represent the melting point? Which phase (curve) would represent the phase change (s)? Which phase (curve) would represent the greatest increa

Gases, Temperature, Current and Reactions

1) Calculate w and Delta E for the expansion of 20.0g of nitrogen gas from a volume of 30.0 L to a volume of 40.0 L at a constant 300.0K. 2) The density of ice at its normal freezing temperature is 0.917g/mL while that of liquid water at the same temperature is 0.9998 g/mL . If Delta H(fusion) of ice is 6.009 kJ/mol, what is

Heat energy and water

I have the data but I am having a hard time determining the end result. How much heat energy is required to raise the temp. of 5.0g of H20 from -10C to 110C ? (ice to steam) Given the following data: Specific Heat J/gK Molar Heat Capacity J/molK Formula Mass Water (l) 4.184

Dealing with Exothermic and Endothermic Reactions

I am in summer school and I missed both of these on my test and my final is cumulative and there will be questions like these on the final. 1. Sketch a diagram representing an exothermic reaction. Label both the horizontal and vertical axes. Show reactants and products, energy of activation and (delta Hrxn) on your sketch.

Calculating percent yield in a reaction

A chemist ran the reaction CH3CH2Cl(l) + KOH(aq) ^ CH3CH2OH(l) +KCL(aq) by heating 47.2 grams of CH3CH2Cl with excess KOH and obtained a yield of 28.7 grams of CH3CH2OH. What was his % yield? I do not know where to begin with this problem. It only gives grams of one reactant? What is the actual yield? Detailed step by step in

How conditions alter rate of enzyme-catalyzed reaction

How will each of the following changes in condition alter the rate of an enzyme-catalyzed reaction: -decreasing temp to 10 deg C? -increasing the pH of the solution from 7 to 11? -heating only the enzyme to 100 deg C?

Calculate delta G; temperature; pressure

Kp is 1.0x10-3 atm-1/2 at 2000K and delta S at standard temperature and pressure = 87.864 J/K mole (delta Cp = 0) for the reaction CO2(g) yielding CO(g) + 1/2 O2(g) (this reaction is reversible) (a) Calculate delta G at 2000K, (b) Calculate delta G at standard temperature and pressure at 298K, and (c) Calculate the degr

Enthalpy Change Cycles

10. Look at the enthalpy cycle below... a) What enthalpy change is represented by delta H1? b) What are the combined enthalpy changes represented by delta H2? c. What enthalpy change is represented by delta H3? d. write and equation that links delta H1, delta H2, and delta H3. e. use the answers from parts a and d and the f

Description of Heat Capacity

Calculate the specific heat capacity of benzene(C6H6), given that 192 J of heat is required to raise the temperature of a 20.0g sample of benzene from 25.2 C to 38.8 C. What is the molar heat capacity of benzene? (the molar heat capacity is the heat capacity of 1 mole of benzene) 3.50 Kcal of heat is removed from a 1.50 Kg

Endothermic Reaction

THE ENDOTHERMIC REACTION A(g) + B(g) 2C(g) PROCEEDS TO AN EQUILIBRIUM CONDITION AT 200 CELSIUS. WHICH OF THE FOLLOWING STATEMENTS IS (ARE) TRUE? 1- If the mixture is transferred to a reaction vessel of twice the volume, the amounts of reactants and products will remain unchanged 2- Addition of an appr

Activation Energy

For the reaction CO+NO2>CO2+NO the activation energy for the forward reaction is 135 kJ/mol of CO activated. a) Determine the heat of reaction. b) From the data given, and the ^Hr for the reaction, determine the activation energy for the reverse reaction.

Moles Produced from Heating

1. How many moles of carbon dioxide will be produced if 50g of potassium hygrogen carbonate are heated? 2. Also, What is the mass of one nitrogen molecule (in grams). Do they mean N_2_? Thanks! : )

Delta Heat for a Reaction

Evaluate Delta H (standard) for the reaction below at 25 degress celcius SiO2 (s) + 4HF (aq) >>>>>>> SiF4 (g) + 2H2O (l) Delta H standard f (kj/mol) -910.9 -320.8 -1615 -285.8

Solubility and Gibbs Free Energy Questions

1. Firstly, how do you calculate the molar solubility of AgBr when given 0.1 M AgBr at 25 degrees C (Ksp = 5 x 10^-3)? If show me a few examples of how to calculate molar solubility when you're given different things, I would appreciate it. 2. Next, how can I calculate the squilibrium direction of CO2 at 25 degrees C and 9

Heat Related Problems

Hi, I need some assistance with the following questions: 1) You have two pieces of Al metal - one is a thin piece of Al foil, and the other is a thick block. Both have the same length and width. Which will absorb more heat when set on a hotplate for the same period of time to raise the temperature 5 degrees? a) Block b) Fo