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December 7, 2016

# Search: Calculate the enthalpy change (delta H...

Number of results: 36,432

Chemistry
The net reaction in a voltaic cell with Eºcell= +.726V 2Fe^3+(aq) + 3Zn(s) --> 2Fe(s) + 3Zn^2+(aq) What is the delta Gº for this reaction at 25ºC I tries using this equation: delta G = -nFEºcell = -n(90485)(.726) However, I don't know how to calculate n in this. I ...
August 9, 2009 by Sara

Chem 2
for the evaporation of water during perspiration on a hot dry day 1.delta H is greater than zero and Tdelta S is equal to Delta H 2.delta H is greater than zero and Tdelta S is gretaer than Delta H 3.delta H is greater than zero and Tdelta S is less than Delta H 4.delta H is ...
April 29, 2007 by ok

chemistry
Q1) For the reaction, A to B, Delta H= +11.00 kJ mol-1 and Keq is 12.50 Calculate i) delta G and ii) delta S at 25 C (degrees celcius) 0 C degrees celcius = 273.15 K; R = 8.314 J K-1 mol-1]
February 15, 2012 by jenny

Chemistry
2)Which of the following equations represents a reaction for which the delta H can be called a standard enthalpy of formation, delta Hf? a) FeO(s) + CO2(g) -> FeCO3(s) b) 1/2 N2(g) + 2 O(g) -> NO2(g) c) 2 Na(s) + Cl2(g) -> 2 NaCl(s) d) Ba(s) + N2(g) + 3 O2(g) -> Ba...
January 21, 2012 by Hannah

Chemistry
I'm trying to write a sentence like this: Exothermic reactions have a negative enthalpy change value because the enthalpy of the reactants are greater than the enthalpy of the products since the reactants have weaker bonds.... Why do weaker bonds have higher energy/enthalpy? I...
February 17, 2013 by a Canadian

chemistry
Calculate the value of DHo for the reaction 2 CH4 (g) -> C2H6 (g) + H2 (g) given the following thermochemical equations: C2H2 (g) + H2 (g) -> C2H4 (g) delta = – 175.1 kJ C2H6 (g) -> C2H4 (g) + H2 (g) Delta = + 136.4 kJ C2H2 (g) + 3 H2 (g) -> 2 CH4 (g) Delta...
January 23, 2012 by timmy

thermodynamics
find change in enthalpy and change in entropy when liquid water at 30¡ãc is converted to steam at 40 bar,375¡ãc.
May 10, 2015 by yajju

chemistry
CaCO2--> CaO+CO2 <-- Calculate the pressure of CO2 in an equilibrium process at (a)22 Celsius and (b) 755 Celsius . Assume delta H=177.8KJ/mol and delta S=160.5 J/mol*K for that temeprature range. My question is do I have to subtract the two temperatures since it says "...
March 1, 2009 by Anonymous

Chemistry
delta T = ikfm delta T is the amount f.p. is lowered. i is the number of particles; i.e., Na3PO4 will have i = 4 (3 for Na and 1 for PO4). m is molality. k is a constant and need not enter into the calculations. Arrange the following solutions in order of decreasing freezing ...
January 21, 2007 by DrBob222

Chemistry
Hydrogen peroxide is used as a bleachin agent, a disinfectant and medicinally as a topical antibacterial agent. Hydrogen peroxide decomposes according to the reacton 2H^2O^2(l)-->2H^2O(l)+o^2(g) A. Given the standard free energy of formation values shown below, calculate ...
May 16, 2007 by Christian

Chemistry
Consider the following data: * NH3(g) yields 1/2 N2(g) + 3/2 H2(g) delta H = 46kJ * 2 H2(g) + O2(g) yields 2 H2o(g) delta H = -484 kJ Calculate delta H for the reaction: 2 N2(g) + 6 H2O (g) yields 3 O2(g) + 4 NH3(g)
November 13, 2011 by Shellby

Chem
How would one calculate change in enthalpy only knowing heat capacities of all substances involved/required? at a known T... WOuld you use a multi-stepped pathway and if so, how?
January 29, 2008 by Supaman

Chemistry
Is the following reaction spontaneous at 25*C? delta s reaction = -217 J/K*mol delta H rxn = -1202 KJ 2Mg (s) + O2 (g) -> 2MgO (s) delta suniverse = delta s system - delta H system / T i got positive (+) 3.81 x 10 ^ 3 J/K and my notes says it is spontaneous but i feel like ...
June 8, 2011 by ChemLover

Chemistry 152
For a certain reaction, the enthalpy change is -148.5 kJ, the entropy change is 256 J/K, and the free energy change is -250.1 kJ. At what temperature is the reaction occurring, in C? Choose one answer. a. 85 b. 102 c. 124 d. 158 e. 210
July 3, 2010 by Car

chemistry
use the following data, as appropriate, to estimate the molarity of a saturated aqueous solution of Sr(IO3)2. Molarity of a saturated aqueous solution of Sr(IO3)2 Sr(IO3)2(s) delt h kJ/mol=-1019.2 delta G kJ/mol=-855.1 delta S= 234 J mol-1K-1 Sr^2+(aq) delta h= -545.8 kJ/mol ...
December 2, 2012 by Allyx3

chemistry
use the following data, as appropriate, to estimate the molarity of a saturated aqueous solution of Sr(IO3)2. Molarity of a saturated aqueous solution of Sr(IO3)2 Sr(IO3)2(s) delt h kJ/mol=-1019.2 delta G kJ/mol=-855.1 delta S= 234 J mol-1K-1 Sr^2+(aq) delta h= -545.8 kJ/mol ...
December 2, 2012 by Allyx3

Find the following limit where f(x) = 4x^2 − 3x. limit-->(f(x+ delta x)-f(x))/(delta x) delta x **delta x means the triangle symbol with x next to it***
September 26, 2011 by kunti

Calculate the minimum change in velocity (delta V or ∆V) required for the Space Shuttle to decrease its altitude to 60 miles if it’s orbiting with an apogee of 236 miles and a perigee of 215 miles above the surface of Earth. Use the rule of thumb that below an altitude...
December 16, 2010 by Vanessa

Chemistry
I did a lab today in class and part of the lab is to experimentally find the enthalpy for the dissolution of ammonium chloride by dissolving 4.0 g of NH4Cl(s) in 50.0 mL of H2O(l). I got a -5°C temperature change and calculated delta H to be 15 kJ/mol. According to the ...
February 13, 2013 by a Canadian

Physics
this question came up in my work, and i don't remember reading about it in my book. can you tell me what it is asking for, and how to do it.. if the change in position delta x is related to velocity v(with units of m/s) in the equation delta x=Av, the constant A has which ...
January 31, 2009 by y912f

chemistry
Calculate te calue of Ksp for Ca(NO3)2 using the data below. Ba(aq) delta G0f= -561 kJ/mol NO3 (aq) delta G0f= -109 kJ/mol BaNO3 (s) delta G0f= -797 kJ/mol
November 27, 2010 by Jeffery

Chemistry
Determine the entropy change when 7.40 mol of HCl(l) boils at atmospheric pressure. I already have the delta Sfus(12.5 J/Kmol) and delta Svap(93.2 J/Kmol), I just cant seem to figure out the last part.
March 30, 2014 by takashi

chemistry
these are my three thermochemical equations 2Cu(s)+S(s) give Cu_2S(s) delta H -79.5 KJ S(s)+O_2 give SO_2(g) -297 KJ Cu_2S(s)+2O_2(g) give 2CuO(s)+SO_2(g) how i calculate standard enthalpy of formation in Kj per mol of CuO(s)? please don't give the answer only guid me please
April 11, 2010 by mohd

chem
Consider the equation A <-> in a 1L container. At 7.57C, the molar concentrations of A and B are 7.228M and 1.976 (respectively). Suddenly, 1.831 moles of A are added to the system. What is the change in deltaG of the system (Answer in kJ) At first, I thought I would use...
April 1, 2007 by Marisol

chemistry
Calculate the change in free energy when you drop 4.70 g of calcium metal into a beaker containing excess water so that Ca(OH)2(s) and H2 gas are formed? The delta-G values you need are in your textbook. The units are kJ.
February 7, 2015 by danny

chemistry
Exactly .203g of zinc metal is dissolved in dilute HCl(aq) in an ice calorimeter. The heat released melts enough ice to produce a volume change of 0.254mL in the ice water mixture surrounding the reaction vessel. Calculate the enthalpy change per mole of zinc for the reaction...
November 15, 2014 by xx

chemistry
Using data in table below and S °(C2H6(g))= 229.5 J·mol-1·K-1, calculate ÄfS° for C2H6(g) in J·mol-1·K-1. Compound S °, J·mol-1·K-1 Compound S °, J·mol-1·K-1 C(s) 5.69 H2(g) 130.6 I am sorry , last time i did not show my working. thanks for helping me . Delta S= ...
May 15, 2010 by write2khin

delta Go = -431.16kJ/mol - (298k X 0.12529 kJ/K*mol) I am having trouble converting the units for delta H and delta s to match. I multiplied delta H by 1000 to get kJ but this didn't give me the correct answer.
April 25, 2012 by Hannah

Chemistry
consider the following reaction: 2CH3OH(g) yields 2CH4(g) + O2(g) change in enthalpy= 252.8kJ Calculate the amount of heat transferred when 26.0 g of {\rm CH_3OH} (g) is decomposed by this reaction at constant pressure.
March 5, 2012 by Dylan

chemistry
From the following information, calculate the standard change of enthalpy for the combustion of coal. C + O2 -> CO2 COMPOUND HEAT OF FORMATION coal 0.0 carbon dioxide -393.5 water (l) -285.9 oxygen 0.0
July 15, 2012 by Annabelle

chemistry check
please check Write the balanced equation, with the enthalpy component, for the rusting process, given that Hf for iron and oxygen is 0 and Hf for ferric oxide is -826 kJ/mol. 4 Fe (s) + 3 O2 (g) --------> 2 Fe2O3 (s) You need to add the heat one of three ways. 4 Fe (s) + 3 ...
February 8, 2007 by key

Chemistry
What is the enthalpy change for the first reaction? Fe2O3(s) → 2Fe(s) + 3/2O2(g) ΔH = 4Fe(s) + 3O2(g) → 2Fe2O3 (s) ΔH = -1,652 kJ I think I'm supposed to rearrange the equation and double everything but enthalpy isn't my strong suit
October 7, 2014 by Hahn

chemistry
a balloonist is preparing a trip in a helium balloon. the trip begins in early morning at a temp of 15 degrees Celcius. By mid afternoon, the temp has increased to 30 degrees C. assuming the pressure remains constant at 1.00 atm, for each mole of helium, calculate: 1. the ...
March 20, 2011 by Joan

general chemistry
A sample consisting of 0.025 mol of a solid compound is placed inside a metal cylinder. The cylinder was immersed in a water bath consisting of 10.00 kg of water at an original temperature of 25.00 °C. When the compound decomposes, the temperature of the water rises to 29.52...
October 23, 2010 by Nora

Chemistry
Consider the following data. DeltaHf (Na2O (s))=-414kJ/mol Delta H sublimation(Na)=109 kJ/mol I.E. (Na)=495 kJ/mol Bond Energy (O2) = 495 kJ/mol E.A. (O) = -141 kJ/mol E.A. (O -) = 878 kJ/mol Use this information to calculate the lattice energy of Na2O (s). So, we have the ...
December 6, 2014 by Anon

chemistry
2CH3OH(l)+3O2(g)→2CO2(g)+4H2O(g Part B Calculate the standard enthalpy change for the combustion of 1 mol of liquid methanol, assuming H2O(g) as a product. Part C Calculate the heat produced by combustion per liter of methanol. Methanol has a density of 0.791 g/mL. Part ...
October 30, 2014 by how do i even start this?

Chemistry
I'm stuck...that is i believe I've come to an impossible answer: I need to calculate the equilibrium constant 4Fe(s) + 3O2(g) --> 2Fe2O3(s) First off: Delta G G Fe(s) = 0, G O2(g) = 0, G Fe2O3(s) = -741 (x2) -741 (2) - 0 = -1480 = delta G of reaction at equilibrium: 0 = (...
April 29, 2010 by Rico

Chemistry
I'm stuck...that is i believe I've come to an impossible answer: I need to calculate the equilibrium constant 4Fe(s) + 3O2(g) --> 2Fe2O3(s) First off: Delta G G Fe(s) = 0, G O2(g) = 0, G Fe2O3(s) = -741 (x2) -741 (2) - 0 = -1480 = delta G of reaction at equilibrium: 0 = (...
April 29, 2010 by Rico

New AP Chem Question for Dr. Bob
This is a Hess' Law problem. I think I got it but I'm hoping you could check it for me: Calculate the heat of reaction for changing 1 mol of silica, SiO2, that has been extracted from sand into the pure silicon that is needed to make computer chips. Use the following data: ...
January 23, 2007 by Belinda

chemistry
A scientist measures the standard enthalpy change for the following reaction to be -172.4 kJ : 2SO2(g) + O2(g) 2SO3(g) Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of SO2(g) is what in kJ/mol?
March 7, 2015 by jojo

Chem Urgent Help
Plz explain in detail.... i tried to search on internet but i am confused with co-efficents.. how to set up the equaiton .. plz help me ??? Bond enthalpy is the energy required to break a mole of a certain type of bond. O=O = 495 kj/mol S-F = 327 kj/mol S=O = 523 kj/mol Use ...
November 12, 2008 by Sarah

Chemistry
Calculate the enthalpy change, ∆H in kJ, for the reaction H2O(s) → H2(g) + 1/2O2(g) Use the following: A. –291.9 kJ B. +291.9 kJ C. –279.9 k D. +279.9 kJ D??
May 19, 2014 by Angela

Chemistry
Consider the following reaction. CH4(g) + 2 O2(g) CO2(g) + 2 H2O(l) ÄH = -891 kJ Calculate the enthalpy change for each of the following cases. 1.00 103 L methane gas at 719 torr and 26°C is burned in excess oxygen.
November 13, 2011 by Bill

Chemistry
Please help, I am having trouble solving these problems at nonstandard temperatures. Methanol burns in oxygen to form carbon dioxide and water. Using the balanced reaction, 2CH3OH(l) + 3OH2(g) --> 2CO2(g) + 4H2O(g) 1) Calculate delta H(rxn) in kJ at 24 degrees Celsius 2) ...
July 18, 2010 by Miguel

pressure change
What is the pressure change for the reaction below at 25 C in the process of reaching equilibrium if there is initially enough ammonium hydrogen sulfide to reach equilibrium? Kp= 4.0*(10^4) NH3(g)+H2S(g) ---><--- NH4HS(s) Answer: 1.0*[10(-2)] Not sure what to do here; I ...
July 20, 2011 by l

Chemistry
Can anyone help me with these three questions? Predict the sign of delta S° and then calculate delta S° for each of the following reactions a. 2H2S(g) + SO2(g) --> 3S(rhombic)(s) + 2H2O(g) b. 2SO3(g) --> 2SO2(g) +O2(g) c. Fe2O3(s) + 3H2(g) --> 2Fe(s) + 3H2O(g) Thank...
May 14, 2015 by Anonymous

Chemistry
Consider a system consisting of 2moles CO2 gas initially at 25 deg and 10 atm and confined to a cylinder of cross section 10.0 square centimeter. lt is allowed to expand adiabatically against an external pressure of 1.0 atm until the piston has moved outwardsthrough 20cm. ...
June 6, 2015 by Rudo Kanukamwe

chemistry
A scientist measures the standard enthalpy change for the following reaction to be -2923.0 kJ : 2C2H6(g) + 7 O2(g) 4CO2(g) + 6 H2O(g) Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of CO2(g) is _________
October 24, 2012 by Anonymous

Chemistry
When a chemist burns ammonia according to the reaction below she finds that the reaction releases heat. (It is exothermic.) 4NH3(g) + 3O2(g) 2N2(g) + 6H2O(g) The enthalpy of the reaction DH = -1267 kJ. What is the enthalpy change (in kJ) when 7 grams of ammonia are burned?
January 12, 2015 by Devin

chemistry 101
The enthalpy change was determined for the following reactions; Ca (s) + CO2 (g) + ½ O2 (g ) → CaCO3 (s) ΔH = -812.8 kJ/mo l Ca (s) + ½ O2 (g) → CaO (s) ΔH = -634.9 kJ/mo l What is the enthalpy change for the following reaction? CaCO3 (s) → CaO (s...
April 29, 2012 by Anonymous

chem
given the thermochemical equations, B2O3 + 3H2O -> 3O2 + B2H6 delta h = -2035 kj H2O -> H2O delta h = 44 kj H2 + 1/2O2 -> H2O delta h = -286 kj 2B + 3H2 -> B2H6 delta h = 36 kj what is the delta hf for 4B + 3O2 -> 2B2O3?
October 17, 2014 by bekah

chemistry
Equilibrium constant K for some reaction at temperature 300K was found to be 100 .Calculate equilibrium for same reaction at 400K if R= 8.23 change in enthalpy is 5000J
August 18, 2014 by shashank

chemistry
consider the following reaction at 298K 4Al(s)+3O2(g) yields 2Al2O3(s) delta H= -3351.4 Kj find delta S sys find delta S surr find delta S unvi
November 20, 2013 by Jessica

Chemistry
consider the following reaction at 298K 4Al(s)+3O2(g) yields 2Al2O3(s) delta H= -3351.4 Kj find delta S sys find delta S surr find delta S unvi
January 29, 2015 by Jake

winterWx
A 0.30-kg softball has a velocity of 12 m/s at an angle of 30° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of 17 m/s, ...
February 23, 2007 by Physics/Math

Chemistry
The combustion of benzoic acid releases 26.38kJ/g and is often used to calibrate a bomb calorimete. The combustion of 1.045g of benzoic acid caused the temperature of the calorimeter to rise by 5.985 degreeC.Using the same calorimeter, a sample of 0.876g of C8H18 was burned. ...
October 9, 2009 by Sindy

Chemistry
2CH3CH2CH2OH(l)+9O2(g)→6CO2(g)+8H2O(g) I have to find the delta G delta G of CH3CH2CH2OH(l)=−360.5 KJ/Mol delta G of O2(g)=0 KJ/Mol delta G of CO2(g)=−394.4 KJ/Mol delta G of H20(g)=−228.6 KJ/Mol I keep getting -3426.2 KJ/Mol but its not correct.
June 21, 2013 by dave

chemistry
For a certain reaction, Delta H(not) = -76.8 kj and delta S(not) = -217 j/k. If n =3, calculate E for the reaction at 25degrees celcius.
November 22, 2010 by Tara

chemistry
For a certain reaction, Delta H(not) = -76.8 kj and delta S(not) = -217 j/k. If n =3, calculate E for the reaction at 25degrees celcius.
November 24, 2010 by Tara

chem
stilll didn't get it .. .. can u plz explain in detail ... how did u get the answer.. plz plz plz plz plzp l zp thnks Bond enthalpy is the energy required to break a mole of a certain type of bond. O=O = 495 kj/mol S-F = 327 kj/mol S=O = 523 kj/mol Use average bond enthalpies ...
November 12, 2008 by DR BOOBB Plz HELP

chemistry
Delta H is given and is-6186.0 Calculate the difference, deltaH-deltaE=delta(PV) for the combustion reaction of 1 mole of methyl octane. (Assume standard state conditions and 298 K for all reactants and products.)
November 14, 2009 by BREE

chem!
i cant figure this one out! :( a balloonist is preparing a trip in a helium balloon. the trip begins in early morning at a temp of 15 degrees Celcius. By mid afternoon, the temp has increased to 30 degrees C. assuming the pressure remains constant at 1.00 atm, for each mole of...
March 21, 2011 by Joan

Analytical Chemistry
When BaCl2-H2O (s) is dried in an oven, it loses gaseious water: BaCl2-H2O <--> BaCl2(s) + H2O (g) enthalpy change - 63.11 kJ/mol at 25 degrees C entropy change - +148 J/(K-mol) at 25 degrees C Calculate the vapor pressure of gaseous H2O above BaCl2-H2O at 298K.
October 25, 2010 by Tammy

Chemistry (How do I calculate)
Calculate the Molar Enthalpy of Neutralization (ΔHn) in kJ/mol of the reaction between a monoprotic acid and a monoprotic base, given the following information: The temperature change equals 6.92°C, 50.0 mL of 1.00 M concentration of Acid 50.0 mL of 1.00 M concentration ...
June 28, 2013 by Ashley

Chemistry
Hydrogen and methanol (CH3OH) have both been proposed as alternatives to hydrocarbon fuels. a) Write balanced chemical equations for the complete combustion of hydrogen and the complete combustion of gaseous methanol. Combustion reaction for hydrogen: 2H2(g)+ O2 --> 2H2O(l...
November 4, 2010 by Jarrod

a. Calculate the delta H, delta G, and equilibrium constant for the reaction of methane with Cl2 to give CH3Cl and HCl. Use the following information for your calculations: Bond Dissociation Energies: CH3-H (104.8kcal/mol), Cl-Cl(59.0 kcal/mol), CH3-Cl(85.0 kcal/mol), and H-Cl...
October 30, 2011 by Natasha

college chem
Calculate the molar enthalpy of reaction standard enthalpy of formation below. H20 = -285.8 kj/mole H+ = 0.0 kj/mole OH- = -229.9 kj/mol H+(aq) + OH-(aq)→H2O(l) For this, don't you do the summation of products x stoichemtry + the sum of reactants x stoich. from there I'm...
November 20, 2014 by sam

Chemistry
I want to know the enthalpy change for this reaction which occurs in a blast furnace: Fe2O3(s) + 3C(s) --> 2Fe(l) + 3CO(g) You will need the heat of formation for CO, and ironIIIoxide, and the heatofmelting for iron. I suspect you have some temperature in mind also which ...
April 15, 2007 by Alice

chemistry
From the following Information, calculate the standard change of enthalpy for the combustion of coal. SHOW WORK AND BALANCED REACTION!!! Compound DeltaHf (kj/mol) Coal 0.0 Carbon dioxide -393.5 Water (l) -285.9 Oxygen 0.0
June 12, 2012 by Chloe

chemistry
From the following Information, calculate the standard change of enthalpy for the combustion of coal. SHOW WORK AND BALANCED REACTION!!! Compound DeltaHf (kj/mol) Coal 0.0 Carbon dioxide -393.5 Water (l) -285.9 Oxygen 0.0
June 12, 2012 by Chloe

Chemistry
A calorimeter contains 30.0 mL of water at 15.0 C. When 1.50 g of X (a substance with a molar mas of 46.0g/ mol is added, it dissolves via the reaction X (s) + H2O (l) ----> X (aq) and the temperature of the solution increases to 26.5 C. Calculate the enthalpy change for ...
March 11, 2016 by Student

chemistry
divide eq 2 by 2: 2H(g)........> H2(g) delta H= -104.2Kcal H(g) ........> 1/2 H2(g) delta H= -72.1Kcal Now reverse the reaction: 1/2H2(g).......>H(g) delta H=+72.1Kcal subtract this eq from eq 1 1/2H(g)+1/2I2(g).....>HI(g) delta H=-1.1kcal +-1/2H2(g)......>+-H(g...
November 28, 2010 by Anonymous

Chemistry
i tried to do like dis plz chk is it rite or wrong. [2(4(327) + 495 ]- [ 2(4(327) + 523 ] = -28 Bond enthalpy is the energy required to break a mole of a certain type of bond. O=O = 495 kj/mol S-F = 327 kj/mol S=O = 523 kj/mol Use average bond enthalpies to estimate the ...
November 13, 2008 by Chem Help

Chemistry
Calculate the temperature change in the water upon complete melting of the ice. Hint: Determine how much heat is absorbed by the melting ice and then use q =mC*Delta T to calculate the temperature change of the 314 g of water. under the following conditions: A 14.7 g ice cube ...
November 18, 2010 by Ricardo

Chemistry
3.25g of zinc was added to 50cm^3 of a 4.0 molar dm^-3 HCl. When the reaction was completed the temperature rose by 28 degrees celcius. (a) Is the reaction exothermic or endothermic? (b)All the zinc dissolve in this reaction. How many moles of zinc reacted? (c) How many moles ...
March 24, 2014 by Jessica

college chemistry
The chemical reaction representing production of water gas is as follows: C(s)+H2O(l)=CO(g)+H2(g) calculate the enthalpy change in the production of 200L(at 500mmHg and 65degree celcius) of hydrogen by this reaction.
November 3, 2008 by bennett

chemistry
If heat of reaction, Ca(s) + 2H+(aq) Ca2+(aq) + H2(g) , is - 544 kJ/mol, heat of reaction, CaO(s) + 2H+(aq) Ca2+(aq) + H2O(l) , is -192 kJ/mol. and heat of formation of water is -286, what is heat of CaO? Ca(s) etc is equation 1. CaO + 2H^+ etc is equation 2. H2 + 1/2 O2 ==>...
February 10, 2007 by nicholas

Chemistry
Which of the following reactions are spontaneous (favorable)? A] 2Mg(s) + O2(g) -> 2MgO(s) Delta G = -1137 kJ/mol .. B] NH3(g) + HCl(g) -> NH4Cl(s) Delta G = -91.1 kJ/mol ... C] AgCl(s) -> Ag+(aq) + Cl-(aq) Delta G = 55.6 kJ/mol .. D] 2H2(g) + O2(g) -> 2H2O(g) ...
March 8, 2012 by Kat

chemistry
You measure Ksp for borax and find it to be 6.2 x 10-3 at 22.8°C. If the standard enthalpy change, ΔH°, for the dissolution of borax is 58 kJ, calculate the standard entropy change, ΔS°, (in J/K) for the dissolution of borax at this temperature. (Assume ΔH° ...
November 19, 2014 by Anonymous

Chemistry 1150
Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic reaction: NH4NO3(s)→NH+4(aq)+NO...
February 25, 2014 by Smith

Chemistry 143
Write three thermochemical equation needed to calculate delta H for the following reaction: 2Mg(s) + O2(g) = 2MgO Include delta h values in kJ for each reaction. Please help!! I don't even know were to start!!
April 26, 2010 by Shana

science, chemistry
2Al(s)+ 3Cl2(g)=2AlCl3(s) For the above reaction calculate: A) delta H, then state whether the reaction is endothermic or exothermic B) delta s, then whether the reaction becomes more or less disorder. C) delta G, the state whether the reaction is spontaneous or non-spontaneous
May 7, 2012 by Bryan

Chemistry
using a coffee calorimeter, it is found that when an ice cube weighing 24.6g melts, it absorbs 8.19kJ of heat. calculate delta H for the phase change represented by the thermochemical equation: H2O(s) ->H2O(l)
April 21, 2014 by Kera

Chemistry
The molar solubility of lead iodide is 1.45*10^-3M at 20 degrees C and 6.5*10^-3M at 80 degrees C . What are the values of delta H not and delta S not for dissolution of PbI2 ? PbI2(s) ---> Pb2+(aq) + 2I- (aq) You may assume that delta H and delta S are independent of ...
November 20, 2010 by Tal

chemsitry
c. Use the enthalpy diagram provided above and apply Hess’s Law to determine the standard enthalpy of formation for C12O36H20N12 (s) using the results from part (a) and the following values: The standard enthalpy of formation of gaseous carbon dioxide is -393.5 kJ/mol The ...
October 23, 2010 by Nora

Thermodynamics
Consider a system consisting of 2.0 mol Carbon dioxide gas, inititially at 25 deg and 10 atm and confined to a cylinder of cross section 10.0square centimeters. lt is allowed to expand adiabatically against an external pressure of 1.0atm until the piston has moved outwards ...
June 6, 2015 by R. Kanukamwe

Chemistry
Calculate the change in enthalpy for the following reaction: C25H52(g) + O2(g) → CO2(g) + H2O(l) I started off by balancing the equation: C25H52(g) + 38O2(g) → 25CO2(g) + 26H2O(l) Can someone help me with the rest.
October 17, 2012 by Dolcezza

Chemistry
If 0.812g of calcium reacts in a coffee-cup calorimeter that contains 400.0g of water/ The initial temperature of the water is 17.9°C, the final temperature is 26.0°C. Calculate the standard molar enthalpy change for this reaction.
January 28, 2016 by Gem

chemistry
A scientist measures the standard enthalpy change for the following reaction to be -53.4 kJ : Ca(OH)2(aq) + 2 HCl(aq) CaCl2(s) + 2 H2O(l) Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of H2O(l) is kJ/mol
March 18, 2012 by Austin

chemistry
A scientist measures the standard enthalpy change for the following reaction to be -53.4 kJ : Ca(OH)2(aq) + 2 HCl(aq) CaCl2(s) + 2 H2O(l) Based on this value and the standard enthalpies of formation for the other substances, the standard enthalpy of formation of H2O(l) is kJ/mol
March 18, 2012 by Austin

Chemistry
Chloroform (CHCL3) has a normal boiling point of 61 'C and an enthalpy of vaporization of 29.24 kJ/mol. What is the value of delta Gvap (in kJ) at 61'C for chloroform?
April 30, 2013 by Chloe

Chemistry
Calculate the enthalpy change, for the process in which 40.0g of water is converted from liquid at 12.8 degrees C to vapor at 25.0 degrees C. For water, traingle Hvap = 44.0kJ/mol at 25.0 degrees C and s = 4.18 J/(g* C) for H2O (l)
November 5, 2010 by Anonymous

Chemistry
Calculate the enthalpy change, for the process in which 40.0g of water is converted from liquid at 12.8 degrees C to vapor at 25.0 degrees C. For water, traingle Hvap = 44.0kJ/mol at 25.0 degrees C and s = 4.18 J/(g* C) for H2O (l)
November 5, 2010 by Anonymous

Chemistry
At 298 K, deltaGo = - 6.36 kJ for the reaction: 2N2O(g) + 3O2(g) ↔ 2N2O4(g) Calculate deltaG (in kJ) at 298 K when PN2O = 3.12 atm, PO2 = 0.0081 atm, and PN2O4= 0.515 Calculate deltaG (in kJ) at 298 K for some solid ZnF2, 0.025 M Zn2+ and 0.038 M F-(aq). Would these two ...
April 3, 2013 by Anonymous

college physic
Determine a formula for the change in surface area of a uniform solid sphere of radius r if its coefficient of linear expansion is alpha A (assume constant) and its temperature is changed by Delta T.Assume the temperature chan ge is not large, Delta T^2 ~ 0.
February 7, 2012 by noah

Chemistry (Thermochemistry)
Is there any equation out there that links the change in enthalpy (H) to the change in cell potential/voltage (E)? Yes, but the relationship involves the Gibbs Free Energy, which is G = H - TS, snd S is the entropy change. The change in G is approximatly the change in H in ...
August 2, 2007 by Vic

chemistry
Given these reactions : X(s) + 1/2O2(g) --> XO(s) (Delta)H= -707.7 kj XCO3(s) --> XO(s)+CO2(g) (Delta)H= +381.9kj What is (delta)Hrxm for this reaction? X(s)+1/2 O2(g)+CO2(g) ---> XCO3(s) (Delta)H= ?
October 28, 2016 by anon

Chemistry
HELP! :) Consider the following reaction: 3A to 2B The average rate of appearance of B is given by deltaB divided by delta t. Comparing the rate of appearance of B and the rate of disappearance of A, we get Delta B divided by Delta t= ___* (-delta A divided by delta t) Thanks!
May 24, 2012 by Mel

UW-River Falls
Calculate the enthalpy change, for the process in which 40.0g of water is converted from liquid at 12.8 degrees C to vapor at 25.0 degrees C. For water, traingle Hvap = 44.0kJ/mol at 25.0 degrees C and s = 4.18 J/(g* C) for H2O (l)
November 5, 2010 by Anonymous

chemistry
use standard enthalpies of formation to calculate delta Hrxn for the following reaction. 2H2S(g)+3O2(g)-->2H2O(l)+2SO2(g) express the answer using four significant figures Delta Hrxn = ? kJ
October 25, 2011 by jen