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Energetics and Thermodynamics

Change in Free Energy: Combustion

Calculate change in Gdegree for the combustion of ethanol vapor, C2H5OH(g), at 750degree C in oxygen to form carbon dioxide and water vapor. The following data is valid at 25 degree C: Changein H degree(KJ/mol) change in Gdegree(KJ/mol) C2H5OH(g) -234.8 -167.9 O2(g) 0 0 H20(g)

Auto-ionization of Water

Kw for the auto-ionization of water, H2o(l) -> H positive(aq) + OH negative (aq) is 1.0 x 10 to the negative 14. Calculate deltaGdegree,DeltaSdegree and DeltaHdegree for the reaction at 25 degree C?

Decomposition of Nitrosyl Chloride

Nitrosyl chloride (NOCl) decomposes at elevated temperatures according to the eqation 2 NOCl(g) <-> 2 NO(g) + Cl2(g) Calculate Kp for this reaction at 227 degrees C. For this reaction change in Hdegree =81.2 KJ/mol, change in Sdegree= 128 J/K x mol

Oxygen and Spontaneous Reactions

The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury oxide: HgO(s)->Hg(l) + (1/2)O2(g) delta H = 90.84 KiloJoule/mol S(Hg)=76.02 J/K x mol S(o2)=205.0 J/K x mol s(HgO) =70.29 J/k x mol Estimate the temperature at which this reaction will become spontaneous under standard state conditions.

Calculating Heat of Combustion

The DH of combustion of CH4 is -882kJ/mol.How many grams of water, which has a specific heat of 4.184 J/g-oC can be heated from 30oC to 95oC by the heat produced in the combustion of 2.25 mol of CH4?

Calorimetry and work

One mole of water evaporates in an open container at 273 Kelvin. The formula is H20 liquid---->>>>H20 gas. What is the work done on or by the system? a. 2.3 kJ b. -2.3 kJ c. 22kJ d - 22kJ

Inorganic Thermodynamics

Calculate the standard enthalpy of formation of gaseous diborane, B2H6, using the following thermochemical information: (See attachment for full question)

Inorganic Chemistry Midterm Study Guide

Please do all of the midterm. These are the sections that will be covered in our midterm please complete with long explanations as well as giving related info to questions asked. Thanks.

Heat Loss and Specific Heat

a) A student wishes to determine the specific heat of a metal using a coffee cup calorimeter (calorimeter constant 50.35 cal/degrees Celsius). The student heats 130.56 grams of unknown metal from 25.0 degrees Celsius to 100.4 degrees Celsius. The initial temperature of the calorimeter (coffee cup plus 30 mL water) was 23.5 degre

Work of expansion

One mole of nitrogen gas confined within a cylinder by a piston is heated from 9.1°C to 883.6°C at 1.30 atm. Calculate the work of expansion (include sign) in joules (1 J = 9.87à?10-3 atm L). Assume all of the energy is used to do work.

Reaction equations and mass

Please give step by step solutions and answers. 1) Write the balanced molecular equation for the reaction of calcium with molecular oxygen to form calcium oxide. 2) You start out with an empty crucible weighing 19.3350g. After adding some calcium to the crucible, the mass is now 22.1156g. After heating the calcium and co

Combustion & Mass

Limestone(CaCO3) is used to remove acidic pollutants from smokestack flue gases in a sequence of decomposition-combination reactions. The limestone is heated to form lime (CaO), which reacts with sulfur dioxide to form calcium sulfite. Assuming a 74.7% yield in the overall reaction, what mass of limestone is required to remove a

Chemistry review questions

Question 2 An imaginary element X consists of two isotopes having masses of 110.00 amu and 112.00 amu. ("amu" is an atomic mass unit.) A sample of X was found to consist of 79.94% 110X and the rest is 112X. What would be the average atomic mass of X in this sample? Give your answer to four significant figures. Do not enter a

Evaluting Melting Point Determination

1. In a mixture of approximately 20% camphor and 80% naphthalene. What would you expect the melting point to be? (+/-)camphor (175-177 Celsius) and naphthalene (80-81 Celsius). 2. Describe the expected type of error in the observed m.p. (unaffected, high, low and/or broad) when the melting point is determined as follows: a.

Entropy of mixing

I am trying to figure out how, for the entropy of mixing of two polymers, one gets from: Change in entropy of mixing (delta S sub m) = k[(N1 + N2) ln (N1 + N2) - N1 ln N1 - N2 ln N2] to the result: change in entropy of mixing (delta S sub m) = -k(N1 ln v1 + N2 ln v2) where v1 and v2 are the volume fractions of the two

What is the percent of CdSO4 by mass in a 1.0 molal aqueous solution?

1. What is the percent of CdSO4 by mass in a 1.0 molal aqueous solution? 2. Calculate the amount of heat that must be absorbed by 10.0 gram of ice at -20 C to convert it to gaseous water at 110 C. Given: Specific heat ice = 2.1 Joule/gram water = 4.184 Joule/gram steam = 1.84 Joule/

Molar enthalpy of vaporization

The normal boiling point of bromine is 58.8 C. Given that the vapor pressure pressure of methanol (sic) is 75.0 torr at 2.5 C, Calculate the molar enthalpy of vaporization of bromine. Show all work and thanks for your help and time.

Vapor Pressure Sample Question

The vapor pressure of ethanol is 400 mmHg at 63.5 C. Its molar enthalpy of vaporization is 39.3 K Joule/mol. What is the vapor pressure of ethanol, in mmHg, at 34.9 C? Show work. For iodine, the molar enthalpy of sublimation is 62.3 k Joule/mol. The molar enthalpy of fusion is 15.3 k/Joule/mol. Calculate the molar enthal

Melting and Vaporizing Substances

Show the heating curve of a subtance that melts and then vaporizes. (a) Sketch the heating curve of carbon dioxide at atmospheric pressure, starting at -100 C and ending at 30 C. (b) Sketch the same heating curve as it would appear at a pressure of 10 atm. (c) Under what conditions would the heating curve resemble the on

Enthalpy Of Solution

Look at the dissolution of various salts. Compare the dissolution of sodium hydroxide with that of sodium chloride. a) How do the energy changes for the overall processes compare? b) Discuss the difference in magnitude of each of the three steps for dissolution of the two compounds.

Heat of formation

Methylene chloride can be prepared from the reaction of methane and chlorine, by the following equation: CH4(g) + Cl2(g) ---> CH2Cl2(g) + HCl(g) Calculate the standard heat of formation in kilojoules for the reaction using the following measured heats of formation. HCl(g) + CH3Cl(g) --> CH4(g) + Cl2(g) Delta H = +98.3 kJ CH

Entropy Change

Question: The reaction of ammonium nitrate when added to water is endothermic (H=25.7 kJ) and can be written as: NH4NO3(s) + H2(l) ---> NH4NO3(aq) a) Determine the heat of formation of NH4HO3(aq). b) What would be the final temperature of a solution that contained 50 grams of NH4NO3 dissolved in 125 mL of water. Use a spec

Metal Heating

Given that: Initial temperature of metal: 20c Final temperature of metal: 100c Initial temperature of water from calorimeter: 20c Final water temperature from calorimeter: 28c 1. What is estimate of specific heat for metal? (use 1 cal/gm°C for water) 2. What is estimate the atomic weight of metal?

Hydrate Formula and Gravimetric of Cloride

1. Given that moles of water loss = Weight of water / GMW H2O (=18.051 ) and moles of CuSO4 = final weight/ GMW CuSO4 (=159.61) :Initial Weight: 116.877g (cooper II sulfate hydrate 30g + water ) :Final Weight: 19.177g (after heat compound with burner) :Weight of Water driven off (Initial weight - final weight) : 97.

Heat Capacity and Calorimetry

When steam condenses to liquid water, 2.26 kj of heat is released per gram. The heat from 168g of steam is used to heat a room containing 6.44 x 10 to the 4th grams of air (20ft x 12 ft x 8 ft). The specific heat of air at normal pressure is 1.015 j/(g.C). What is the change in air temperature, assuming the heat from the stea

Calorimetry

In a coffee-cup calorimeter, 1.10 g of NH4NO3 is mixed with 76.0 g of water at an initial temperature of 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents is 23.93°C. Assuming the solution has a heat capacity of 4.18 J/°C · g and assuming no heat loss to the calorimeter, calculate the

Calculating enthalpy change

The bombardier beetle uses an explosive discharge as a defensive measure. The chemical reaction involved is the oxidation of hydroquinone by hydrogen peroxide to produce quinone and water. Please see the attached file for full problem description.

Enthalpy Change for Dissolution

In a coffee-cup calorimeter, 1.10 g of NH4NO3 is mixed with 76.0 g of water at an initial temperature of 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents is 23.93°C. Assuming the solution has a heat capacity of 4.18 J/C/g and assuming no heat loss to the calorimeter, calculate the entha