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September 20, 2014

Search: Calculate the enthalpy change (delta H..

Number of results: 28,426

CHEMISTRY
I know I posted this question before, but can you clarify it?? MY QUESTION IS AFTER YOU SWITCHED THE DELTA H1 THE CHANGE IN THE ENTHALPY IS NEGATIVE.... BUT THAT DOES NOT MAKE SENSE BECAUSE THE CHANGE IN ENTHALPY OF THE ORIGINAL DELTA H1 IS NEGATIVE(ACCORDING TO THE ...
November 14, 2013 by Anonymous

Chemistry
I know I posted this question before, but can you clarify it?? MY QUESTION IS AFTER YOU SWITCHED THE DELTA H1 THE CHANGE IN THE ENTHALPY IS NEGATIVE.... BUT THAT DOES NOT MAKE SENSE BECAUSE THE CHANGE IN ENTHALPY OF THE ORIGINAL DELTA H1 IS NEGATIVE(ACCORDING TO THE ...
November 14, 2013 by Anonymous

Chemistry
Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 C2H2+2H2---->C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below? C2H4+H2---->C2H6 Delta H = ? A. Delta H 1 + ...
November 11, 2013 by Anonymous

CHEMISTRY
Please explain. The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 C2H2+2H2---->C2H6 Delta H 2 Which expression represents the enthalpy change for the reaction below? C2H4+H2---->C2H6 Delta H = ? A. Delta H 1 + Delta...
November 11, 2013 by Anonymous

Chemistry
Calculate the work involved if a reaction with an enthalpy change of -2418 kJ is carried out in a vessel with a mobile, frictionless piston. Other details: the reaction is H2(g) + 1/2Oxygen2(g) yields H2O(g) with enthalpy change of -241.8 kJ/mol. The product is 180.16gH2O=10....
November 23, 2008 by Mark

Chemistry
Calculate the enthalpy change (delta H) in kJ for the following reaction. 2Al(s) + Fe2O3 (s) ==> 2 Fe(s) + Al2O3(s) use enthalpy changes for the combustion of aluminum and iron. 2Al(s) + 3/2 O2(g) ==> Al2O3(s) Delta H: -1669.8 kJ 2Fe(s) + 3/2 O2(g) ==> Fe2O3 (s) Delta...
May 23, 2010 by Kim

Chemistry
Calculate the enthalpy change (delta H) in kJ for the following reaction. 2Al(s) + Fe2O3 (s) ==> 2 Fe(s) + Al2O3(s) use enthalpy changes for the combustion of aluminum and iron. 2Al(s) + 3/2 O2(g) ==> Al2O3(s) Delta H: -1669.8 kJ 2Fe(s) + 3/2 O2(g) ==> Fe2O3 (s) Delta...
May 23, 2010 by Kim

Chemistry!
Calculate the work involved if a reaction with an enthalpy change of -2418 kJ is carried out in a vessel with a mobile, frictionless piston. Other details: the reaction is H2(g) + 1/2Oxygen2(g) yields H2O(g) with enthalpy change of -241.8 kJ/mol. The product is 180.16gH2O=10....
November 23, 2008 by Elizabeth

AP Chemisty
N2(g)+3F2 yields 2Nf3(g) Delta H(degree)298=-264KJ mol-1;Delta S(degree)298=-278J K-1 mol-1 The following questions relate to the synthesis reaction represented by the chemical equation above. a.)CAlculate the value of the standard free energy change, Delta G(degree)298, for ...
June 7, 2007 by Jenna

CHEM
Can you please check my work? I got -4.3KJ/mol If this is not right can you tell me what I am doing wrong? Thank you! Questions. 1.a. Use Hess's Law and the measured mean enthalpy changes for the NaOH-HCl and NH3-HCl reactions to calculate the enthalpy change to be expected ...
November 8, 2013 by Lauren

chemistry
Calculate the enthalpy of change, Delta H of rxn, for each of the reactions. record the values in the data table part 2 I calculated the heat of rxn of the HCl +NaOH------NaCl + H2O. How do i go from here to enthalpy of change
January 8, 2012 by AP Chemistry Question

Chemistry
CONTINUE>>>>>>>>>>> The enthalpy changes for two different hydrogenation reactions of C2H2 are: C2H2+H2---->C2H4 Delta H 1 (there is a degree sign....standard enthalpy of formation??) *****WAIT A SECOND, IF I USE THE HEAT OF FORMATION ...
November 14, 2013 by Anonymous

Chemistry
"Translate the empirical molar enthalpy given below into a balanced chemical equation, including the enthalpy change (delta H): The standard molar enthalpy of formation for carbon disulfide is 89.0 kJ/mol" I got delta H = 178 kJ (is that right?). However, I'm having trouble ...
February 12, 2010 by Stuck

Chemistry - Enthalpy change and stoichiometry
N2 + O2 = 2NO enthalpy change = +180.6kJ c) what is the enthalpy change for the formation of one mole of nitrogen monoxide? d) What is the enthalpy change for the reaction of 1.000 * 10^2g of nitrogen with sufficient oxygen? I do not understand how to calculate the above, can ...
February 23, 2011 by Farah

chemistry... HELP !!!!!!!
The average bond enthalpy for C__H is 413 kJ/mol. In other words, 413 kJ of energy is required to break a mole of CH into atoms: CH (g) ----> C(g) + H(g) delta H= 413 kJ Using this information, and enthalpy of C6H6=5535kJ, calculate the enthalpy change of the reaction: C6H6...
November 18, 2012 by sarah

Chem
RXN #1: H2 (g) + O2 (g) --> H2O2 (l) ; delta-H =? Calculate the enthalpy change (delta-H1) for the reaction above (RXN #1) using the information below and Hess' Law. RXN A: H2O2 (l) --> H2O (l) + 1/2 O2 (g); delta-H=-98.0 kJ/mol RXN B: 2 H2 (g) + O2 --> 2 H2O (l); ...
July 12, 2011 by Ally

12 Chemistry
What is the molar enthalpy of combustion of magnesium? This was the lab question that I was asked to find after performing a lab based on Hess' law. I can't find anywhere in my notes how to calculate this, and the text book doesn't explain their steps properly, and I have ...
March 29, 2008 by Chase (sorry if this long)

Chemistry
Given 2Al2O3 (s) --> 4Al(s) + 3O2 (g) (standard enthalpy change= 3351.4 kJ) a) What is the heat of formation of aluminum oxide? How do I find heat of formation from standard enthalpy change? I know how to do it when I'm given enthalpy, but they aren't the same thing- ...
January 31, 2007 by Chris

chemistry
Consider the gold-platinum system which has a value of delta w of -4250 J/mole; (a) Calculate the enthalpy of mixing for a solution of 10% platinum and 90% gold. Express your answer in units of kJ/mole. (b) Is the dissolution of 10% platinum into gold an endothermic or an ...
May 4, 2013 by ssss

Chemistry
Consider the gold-platinum system which has a value of delta w of -4250 J/mole; (a) Calculate the enthalpy of mixing for a solution of 10% platinum and 90% gold. Express your answer in units of kJ/mole. (b) Is the dissolution of 10% platinum into gold an endothermic or an ...
December 11, 2012 by Odesa

Chemistry
Consider the gold-platinum system which has a value of delta w of -4250 J/mole; (a) Calculate the enthalpy of mixing for a solution of 10% platinum and 90% gold. Express your answer in units of kJ/mole. (b) Is the dissolution of 10% platinum into gold an endothermic or an ...
December 13, 2012 by Ling

Chemistry
Reposted: Use Hess's law to calculate the enthalpy change for the reaction: 3C(s) + 3H2(g) yield C3H6(g) Given the following thermochemical equations: 2C3H6(g) + 9O2(g) yield 6CO2(g) + 6H2O(l) enthalpy change= -4116.0 kJ/mol C(s) + O2(g) yield CO2(g) enthalpy change= -393.51 ...
March 17, 2012 by Hailee

Chemistry
Calculate the enthalpy change for the reaction: 2S(s) + 3O2(g) --> 2SO3(g) Use the following thermochemical equations: Reaction S(s) + O2(g) --> SO2(g) Delta H(in kJ) -296.8 2SO2(g) + O2(g) --> 2SO3(g) Delta H(in kJ) -197.0
October 13, 2010 by Jordin

Chemistry
Calculate the DELTA H(rxn), DELTA S(rxn), DELTA S(universe), DELTA G(rxn). For each system below indicate whether DELTA S and DELTA H are positive or negative. Then indicate if the reaction is entropy driven, enthalpy driven or neither. C3H8(g) + 2O2(g) => 3CO2(g) + 4H2O(g)
September 19, 2008 by Zach

chemistry
How to calculate enthalpy change of the following reaction? : S + 2h2o >>> so2 + 2h2 given: s+o2 >>> so2 - enthalpy change = -296.8 kJ h2 + 1/2o2 >> h20 enthalpy change= -285.8kj I was trying to solve it myself but i got confused.. i know i have to ...
April 19, 2010 by olexandra

chemistry
Calculate enthalpy change of reaction for the combustion of gaseous ethanol. C2H5OH + 3O2 >> CO2 + 3H2O. Using standard molar enthalpies of formation. C2H5OH -235.3 ( it's negative sign) CO2 -393.5 H2O -241.8 (1) Calculate the enthalpy change of reaction per mole of ...
April 20, 2010 by Alex

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 I keep using equation delta G=delta H-T(...
July 3, 2010 by Car

Chemistry
Calculate the enthalpy of the reaction 2B2H6 + 6O2=2B2O3 +6H2O given the following pertinent information: A. B2O3(s) + 2H2) )g) = 3O2 (g) + B2H6 (g), delta H= +2035kJ B. 2B (s) + 3H2 (g) =B2H6 (g), delta H= +36 kJ C. H2 (g) + 1/2)2 (g) =H2O (l), delta H=-285 D. H2O (l) = H2O (...
April 22, 2012 by B

Chemistry
Calculate the entropy change in the surroundings when 1.00 mol N2O4(g) is formed from 2.00 mol NO2(g) under standard conditions at 298 K. I get +192 J/K. The book says -192 J/K. Here is my work, where am I going wrong? Standard Enthalpy of NO2(g) = 33.18 kJ/mol * 2 mol = 66.36...
February 21, 2009 by chemstudent

Chemistry
Enthalpy changes: H2O2(l) ----> H2O(l) + 1/2P2(g) delta H= -94.6kJ H2(g) + 1/2O2(g)----> H2O2 delta H= -286.0kJ Calculate the value on delta H for the reaction: H2(g) + H2O2(l)----> 2H2O(l)
May 19, 2012 by Megan

chem
calculate the change in enthalpy when 1.00g of hydrogen peroxide decomposes. H2O2(l) yields H2O(l)+ 1/2O2(g) (traingle)H- -98.2kj I will be happy to critique your thinking on this. help me? You know the delta H is for one mole decomposition. So figure the fraction of 1gram/one...
April 12, 2007 by crystine cole

college chemistry-thermochemistry
i have one more question: I know this one has to do with hess's law but i'm not sure of how to get the enthalpy of vaporization from this? Clculate the enthalpy of vaporization of solid potassium bromide to a gas of ions, the process KBr--->K{+1}(g)+Br{-1}(g), from the ...
November 8, 2008 by maryanne

Physics
1. If the change in position delta(x) is related to velocity v (w/ units of m/s) in the equation delta(x)=Av, the constant A has which dimension? a. m/s^2 b. m c. s d. m^2 2. If a is acceleration (m/s^2), delta(v) is change in velocity (m/s), delta(x) is change in position (m...
August 29, 2009 by anonymous

Chemistry
Data: C(graphite) + O2(g) forms CO2 (ga) Delta H = -393.5kJ H2(g) + 1/2O2(g) forms H2O(l)Delta H = 285.8kJ. CH3OH(l) + 3/2O2(g)forms CO2(g) + 2H2O(l)Delta H = -726.4 Using data above, calculate the enthalpy change for the raction below C(graphite) + 2H2 +1/2 O2(g) forms CH3OH(l)
October 27, 2010 by lavonne

chemistry
Ok, I really need to know how to work problems like these so could someone please show me how to set it up?! Given this data: 1. C(graphite) + O2(g) produces CO2(g), delta H = -393.5 kJ 2. H2(g) + 1/2 O2(g) produces H2O(l), delta H = -285.8 kJ 3. Ch3OH(l) + 3/2 O2(g) produces ...
November 23, 2010 by lavonne

chemistry
use the following data to calculate the mean bond enthalpy values for the C-H and C-C bonds. CH4(g)-C(g) + 4H(g) standard enthalpy change is +1648 kj/mol C2H6(g)-2C(g) + 6H(g) standard enthalpy change is +2820 kj/mol
February 22, 2013 by Bliss

Chemistry
If you can show me an example of one problem, I have no idea how to approach this. Calculate where the number 40.67 came from. Use the Clapeyron-Clausisus equation. Assuming that delta H vap does not change with temperature, this equation relates the change in vapor pressure ...
February 26, 2012 by Angel

Chemistry
2M +6HCl>2MCl+3H2 Delta H= -638.0 Kj HClg>HCl aq= Delta H -74.8 Kj H2+Cl2>2HCl Delta H -1845.0 Kj MCl3s> MCl3 aq Delta H -249.0 Kj Use the information above to determine the enthalpy of the following reaction. 2M +3Cl2>2MCl3 Delta H =???
March 22, 2013 by Raul

chemistry
Given the following reaction and enthalpy change, calculate the amount of heat for converting 100.4g of liquid water (18.02g/mole) to a vapor? delta H= +44kJ
November 3, 2011 by Teresa

Chemistry
O3 + NO --> O2 + NO2 (all in gas state) Calculate the change in enthalpy for the reaction at room temp. using the following data ^Hf: O3 = 143 NO = 90 NO2 = 33 So, I have 143+90--> X + 33. I don't know what the enthalpy of O2 is. I assume you simply subtract the enthalpy...
February 18, 2008 by Anonymous

Chemistry
Give the enthalpy change and entropy change values shown below calculate the free energy change for this reaction at 25 degrees C using Gibbs free energy equation. How does this value compare to the free energy change using the standard free energy of formation data? delta H=-...
May 16, 2007 by Christian

Chemistry
"Given that the bond enthalpy of the carbon-oxygen bonds in carbon monoxide and carbon dioxide are 1073 kJ/mol and 743 kJ/mol respectively, and that of the bond in the oxygen molecule is 496 kJ/mol, calculate the enthalpy change for the combustion of 1 mole of carbon monoxide...
April 8, 2010 by Stuck

College (Enthalpy) - College
S(rhombic)+O2(g)--->SO2(g) change in H(rxn)= -296.06 kJ/mol S(monoclinic)+O2(g)--->SO2(g) change in H(rxn)= -296.36 kJ/mol 1. Calculate the enthalpy change for the transformation. S(rhombic)-->S(monoclinic) Our goal is to calculate the enthalpy change for the ...
October 31, 2010 by Lucy

physical chemistry
1.) Calculate delta rH for the freezing of water at one bar and -10 degrees C. The heat capacities are H2O(s)=36.9 JK-1mol-1 and H2O(l)=74.5JK-1mol-1. delta H for freezing of water at 0 degree C is -6602Jmol-1 (assume C is independent of temperature). 2.) Assume the hot brick ...
February 21, 2012 by nicole

Chemistry
If delta Hrxn and delta Srxn are both positive values, what drives the spontaneous reaction and in what direction at standard conditions? The spontaneous reaction is a)enthalpy driven to the left. b)entropy driven to the right. c)entropy driven to the left. d)enthalpy driven...
April 20, 2014 by Alexis

Chemistry
Calculate the work involved if a reaction with an enthalpy change of -2418 kJ is carried out in a vessel with a mobile, frictionless piston. Other details: the reaction is H2(g) + 1/2Oxygen2(g) yields H2O(g) with enthalpy change of -241.8 kJ/mol. The product is 180.16gH2O=10....
November 22, 2008 by Mark

Science: Chemistry - Enthalpy
The enthalpy change in the combustion of the hydrocarbon octane is delta H = -5.48 x 10^3 kJ/mol C8H18(l). How much heat, in kilojoules, is liberated per gallon of octane burned? (Density of octane = 0.703 g/mL; 1 gal = 3.785 L.)
June 8, 2011 by Jackie

Chemistry
calculate the enthalpy change in delta H foor heating 250 grams of liquid water from 0 degrees celcius to 100 degrees celcius.
February 11, 2011 by Bri

Chemistry
The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta H= -74.9 kJ/mol (...
October 31, 2010 by Kristin

Chemistry- college
The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta H= -74.9 kJ/mol (...
November 1, 2010 by Willy

Chemistry
I am having trouble with this equation and calculating the enthalpy of formation. 2 NaHCO3 (s) --> Na2CO3 (s) + H2O (g) + CO2 (g) delta H129.2kj I get as far as this step and then I dont know what to do next. delta H= [1*delta H (Na2CO3) + 1* delta H(H2O (g)) + 1* delta H(...
April 30, 2013 by Laura

Chemistry
calculate the enthalpy change for: (enthalpy of formation of aqueous sodium hydroxide is -469.60 kJ/mol. enthalpy of formation of liquid water is -285.8 kJ/mol) 2Na + 2H2O = 2 NaOH + H2
January 31, 2013 by Annie

Chemistry
You wish to know the enthalpy change for the formation of liquid PCl3 from the elements shown below. P4(s) + 6 Cl2(g)--> 4 PCl3(l) ΔHf = ? The enthalpy change for the formation of PCl5 from the elements can be determined experimentally, as can the enthalpy change for ...
May 1, 2011 by Kat

chemistry
HNO3 (g) + 4H2 (g) NH3 (g) + 3H2O (g)deltaH = -637 kJ Calculate the enthalpy change when one mole of hydrogen reacts and What is the enthalpy change when 10.00 g of ammonia is made to react with excess of steam to form nitric acid and hydrogen gases?
March 8, 2008 by cooper

chemistry
HNO3 (g) + 4H2 (g) ---> NH3 (g) + 3H2O (g) deltaH = -637 kJ Calculate the enthalpy change when one mole of hydrogen reacts; and What is the enthalpy change when 10.00 g of ammonia is made to react with excess of steam to form nitric acid and hydrogen gases?
March 8, 2008 by cooper

chem
HNO3 (g) + 4H2 (g) ---> NH3 (g) + 3H2O (g) deltaH = -637 kJ Calculate the enthalpy change when one mole of hydrogen reacts; and What is the enthalpy change when 10.00 g of ammonia is made to react with excess of steam to form nitric acid and hydrogen gases?
March 8, 2008 by Anonymous

Chem
Change in enthalpy problem. Consider the reaction represented below. Referring to the data in the table below, calculate the standard enthalpy change for the reaction at 25 degrees C. O3(g)+NO(g)-->O2(g)+NO2(g) Standard enthalpy of formation in kJ/mol: O3(g) 143 NO(g) 90 ...
November 19, 2007 by Dan

Chemistry II
Calculate the enthalpy change in kilojoules when 54.7g of MgCO3 decomposes according to the following equation: MgCO3 (s) into MgO (s) + CO2 (g) My delta H answer was 100.6 KJ but the real answer is 76.1 KJ. Can someone please help?
November 29, 2009 by Mandy

Chemistry
Calculate the change in internal energy at 1 atm & 25C. H2 (g) + 1/2 O2 (g) ---> H2O (l) delta(H)= -286 KJ/mol Okay so i started with the equation: delta(E) = delta(H) - RTdelta(n) P= 1 atm T= 298 K but i dont exactly know what to do from here..please help thank you.
August 27, 2011 by ChemLover

Chemistry
given that: delta H [Cl(g)]=121.3 kJ*mol^(-1) delta H [C(g)]= 716.7 kJ*mol^(-1) delta H [CCl(subscript 4)(g)] =-95.7kJ*mol^(-1) calculate the average molar bond enthalpy of the carbon-chlorine bond in a CCl(subscript 4) molecule.
April 8, 2013 by anonymous

chemistry
CH3OH(g) ----> CO(g) + 2H2 (g) (delta H =+90.7k) A) is heat absorbed or released in the course of this reaction? b) calculate the amount of heat transferred when 45.0g of CH3OH(g)is decomposed by this reaction at constant pressure. c) for a given sample of CH3OH, the ...
October 17, 2011 by Anna

Chemistry
Consider the following two thermochemical equations N2+2.5O2-> N2O5(s) Delta H=xkJ N2+2.5O2-> N2O5(g) Delta H=ykJ The enthalpy change in kJ for the sublimation of one mole of N205 solid to gas would be represented by the quantity a)x+y b)x-y c)y-x d)-x-y Assuming it's a)
July 24, 2010 by Bob

Chemistry
Hydrogen sulfide, H2S is a foul smelling gas. It burns to form sulfur dioxide. 2H2S +3O2 ----> 2N2 +6H2O Delta H=-1036kJ Calculate the enthalpy change to burn 26.7 g of hydrogen sulfide.
October 29, 2007 by Lauren

Chemistry
Part A Calculate the standard enthalpy change for the reaction 2A+B --->2C +2D Use the following data: Substance Delta H(kJ/mol) A -263 B -391 C +203 D -523 Express your answer in kilojoules. MY ANSWER FOR PART A: Delta H =277 kJ PART B----THIS ONE I NEED HELP ON Express ...
June 16, 2011 by tina

Chemistry
Part A Calculate the standard enthalpy change for the reaction 2A+B --->2C +2D Use the following data: Substance Delta H(kJ/mol) A -263 B -391 C +203 D -523 Express your answer in kilojoules. MY ANSWER FOR PART A: Delta H =277 kJ PART B----THIS ONE I NEED HELP ON Express ...
June 16, 2011 by tina

Chemistry
H2 + F2--> 2HF deltaH = 518.0 kJ H2 ----> 2H deltaH = 436.8 kJ F2 ---> 2F deltaH = 158.2 kJ (a) calculate Delta H for H + F---> HF (b) what is the standard enthalpy change of formation of F2 Help please!!! i think this is easier than i'm making it. for (b) would i ...
April 28, 2011 by jessica

gen Chem
I've attempted this problem but not sure if i'm on the right track. Use the enthalpy diagram provided above and apply Hesss Law to determine the standard enthalpy of formation for C12O36H20N12 (s) using the results from part (a) and the following values: The standard enthalpy...
October 26, 2010 by Vince

Chemistry
Consider the following two thermochemical equations N2+2.5O2-> N2O5(s) Delta H=xkJ N2+2.5O2-> N2O5(g) Delta H=ykJ The enthalpy change in kJ for the sublimation of one mole of N205 solid to gas would be represented by the quantity a)x+y b)x-y c)y-x d)-x-y I am thinking it...
July 25, 2010 by Bobz

Chemistry
The oxidation of copper(I) oxide, Cu2O(s), to copper(II) oxide, CuO(s), is an exothermic process, 2 Cu2O + O2 --> 4CuO The change in enthalpy upon reaction of 75.30 g of Cu2O(s) is -76.83 kJ. Calculate the work, w, and energy change, ΔUrxn, when 75.30 g of Cu2O(s) is ...
November 4, 2013 by chemgeek

Chemistry
Someone said, "Calculate the total delta H of the reaction and subtract the total delta H of the product from it. If you get a positive value, it radiates heat which means it's exothermic. If it is negative, heat is needed to get a reaction so it is endothermic." ...shouldn't ...
February 11, 2013 by A Canadian

Chemistry
Someone said, "Calculate the total delta H of the reaction and subtract the total delta H of the product from it. If you get a positive value, it radiates heat which means it's exothermic. If it is negative, heat is needed to get a reaction so it is endothermic." ...shouldn't...
February 11, 2013 by A Canadian

Chemistry-College
S(rhombic)+O2(g)--->SO2(g) change in H(rxn)= -296.06 kJ/mol S(monoclinic)+O2(g)--->SO2(g) change in H(rxn)= -296.36 kJ/mol 1. Calculate the enthalpy change for the transformation. S(rhombic)-->S(monoclinic) Our goal is to calculate the enthalpy change for the ...
October 31, 2010 by Lucy

chemistry
Determine the enthalpy for the partial combustion of methane to carbon monoxide- 2CH4(g) + 3O2(g) = 2CO(g) + 4H2O(l) from change in enthalpy (CH4,g) = -890. kJ mol-1 and change in enthalpy (CO,g) = -283.0 kJ mol-1
September 20, 2009 by Anna

Chemistry- please help ASAP!!!! thank you
S(rhombic)+O2(g)--->SO2(g) change in H(rxn)= -296.06 kJ/mol S(monoclinic)+O2(g)--->SO2(g) change in H(rxn)= -296.36 kJ/mol 1. Calculate the enthalpy change for the transformation. S(rhombic)-->S(monoclinic) Our goal is to calculate the enthalpy change for the ...
October 31, 2010 by Annabelle

Chem
The bond enthalpy of N2(g) is 418.0 kJ/mol. Calculate delta Hf for N(g).?
October 2, 2010 by Trinh

Calculus-Solved - Incorrect
calculate delta y for f(x)= x^(3/2) with x= 4 and delta x= dx=0.1 delta y= f(x+delta x)- f(x) = f(4.1) - f(4) delta y= f(4.1)-8 f(x + delta x)= 8 + 3/2*x^(1/2)*0.1 = 8 + 0.15x^(1/2) = 8 + 0.30 = 8.30 delta y= 8.30 - 8 delta y= 0.30 but this is wrong. why is it wrong?
May 4, 2013 by Alaina

Chemistry
How many grams of MgO are produced during an enthalpy change of -96.0 KJ if 2Mg(s) + O2(g) -> 2MgO(s) and delta H= -1204kj
August 13, 2013 by Carolyn

Chem
For the reaction, 3C2H2(g) ===> C6H6 at 25C, the standard enthalpy change is -631 kJ and the standard entropy change is -430 J/K, Calculate the standard free energy change (in kJ) at 25C. What is the formula that relates stand. entropy, enthalpy and free energy changes?
March 30, 2008 by Ginger

Chemistry II
Calculate the enthalpy for the following reaction: 4 NH3 (g) + 5 O2 (g) into 4 NO (g) + 6 H2O (g). You may only use the following information: N2 (g) + O2 (g) into 2 NO (g); Delta Hf = 180.6 kJ N2 (g) + 3 H2 (g) into 2 NH3 (g); Delta Hf = -91.8 kJ 2 H2 (g) + O2 (g) into 2 H2O...
November 29, 2009 by Mandy

chemistry
Data: SO2(g)+ 1/2O2(gas)forms SO3(g)Delta H = -99.1 kJ. Given the above data, calculate the enthalpy change when 89.6 g of SO2 is converted to SO3. Is this a grams to moles conversion or what? I can't find any examples of this type of calculation.
October 27, 2010 by lavonne

Chemistry
Calculate the standard enthalpy change for the reaction 2C8H18(l)+17O2(g)> 16CO(g) + 18H2O(l) Given 2C8H18(l)+25O2(g)>16CO2(g)+18H2O(l) deltaH=-11020 kj/mol 2CO(g)+ O2(g)>2CO2(g) Delta H=-566.0 kj/mol The > is supposed to be an arrow :)
November 17, 2011 by Nicole

Chem
For the reaction I2(s)+Cl2(g) ==> 2ICl(g) delta H= 36kJ, delta S= 158.8J/K at 25 C. Calculate the temperature at which Keq is 4.0*10^3. delta G= (delta H)- T(delta S) = 36 - (298)(0.1588) = -11.32 delta G= -RTlnK -11.32= -8.31Tln(4*10^3) -11.32= -6892.35 T T= .00164 > ...
August 10, 2009 by ---

chemistry
give enthalpy profile diagrams to illustrate endothermic and exothermic reactions. include an explanation of cocepts such as enthalpy change, activation energy and catalysts.explain how the process of bond breakage and formation determine the enthalpy change of a reaction ...
February 2, 2011 by ABRAHAM

APChemistry
Thank you!!! Do catalysts affect: A, B, C, AB, AC, BC, or ABC???: where: A)activation energy B) enthalpy change (I am assuming this is delta H) C) value of the equilibrium constant thank you!!!
May 10, 2010 by GRATEFUL AP CHEMISTRY STUDENT

chemistry
what two conditions must be met by a thermochemical equation so that its standard enthalpy change can be given the symbol delta Hf?
October 12, 2010 by Leslie

chemistry
How many enthalpy changes (Hs) would be required to calculate the total enthalpy change when ice at 0.0oC is turned to steam at 100.0oC?
February 20, 2014 by Anonymous

Chemistry for Eng.
Select the delta H values associated with the dissolution of lithium chloride that are exothermic. delta H1: energy associated with the separation of water molecules delta H2: energy associated with the separation of ions delta H3: energy associated with the formation of water...
November 1, 2012 by Anonymous

Chemistry
The standard free energy change, delta f G, for the formation of NO (g) from its elements is +86.58 kJ/mol at 25 degrees C. Calculate Kp at this temperature for the equilibrium 1/2 N2(g) + 1/2 O2(g) = NO(g) Comment on the sign of delta G and the magnitude of Kp.
April 30, 2014 by Sha

chemistry
I have two questions regarding enthalpy of reactions: 1.) Care must be taken when dissolving NaOH pellets in water because the temp. can rise dramatically. Taking NaOH as system, what can be deduced about the signs of the entropy of system and surroundings? Am I correct in ...
May 2, 2014 by Rebecca

chemistry
If someone could see if I have the right answers, and if I don't maybe give me some hints on what to do to get to the right answerr, please. 1. Calculate the heat required to raise the temperature of 150g of water by 25.0C. [For pure water specific heat capacity=4.18Jg^-1K^-1...
November 10, 2009 by Anonymous

Chemistry
Calculate the change in the enthalpy of the reaction. C4H4(g)+2H2(g)===>C4H8(g) Use the following: change in enthalpy of combustion for: C4H4=-2341 kJ mol-1 H2=-286 kJ mol-1 C4H8=-2755 kJ mol-1
October 25, 2009 by Natalie

Enthalpy Change?
Given the thermochemical equation SO2(g) + O2(g) SO3 (g) DH = -99.1 kJ calculate the enthalpy change (DH) when 89.6 g of SO2 is converted to SO3 a. -69.3 kJ b. -139 kJ c. 69.3 kJ d. 139 kJ e. -111 kJ
June 12, 2009 by JennyB

College Chemistry
Predict the signs of delta H (Enthalpy) and delta S (Entropy) for the evaporation of water at 85 C.
November 9, 2010 by James

Chemistry
For the reaction described by the chemical equation: 3C2H2(g) -> C6H6(l) .. Delta H rxn = -633.1 kJ/mol a) Calculate the value of Delta S rxn at 25.0 C... b) Calculate Delta G rxn... c) In which direction is the reaction, as written, spontaneous at 25 C and 1 bar pressure...
March 9, 2012 by Katherine

Chemistry
Which of the following is the best definition of Hess' Law? A. Since enthalpy is a state function, it will be different if a reaction takes place in one step or a series of steps. B. Heat is always released by the decomposition of 1 mole of a compound into its constitute ...
February 24, 2008 by Anonymous

Physics
please check if these are right 1. Which of the following is the equation for average velocity? a. Vavg=delta x/delta t b. Vavg=delta t/delta x c. Vavg=delta x *delta t d. Vavg=V1-Vf/2 i picked A 2. Suppose you are given a position versus time graph. the slope of a line drawn ...
January 30, 2009 by y912f

Chemistry- HWK CHECK
1. A solution in which no more solid can be dissoved is referred to as ____. Answer: saturated 2.At constant pressure, heat can be referred to as (entropy, enthalpy, or free energy). Answer: enthalpy The measure of disorder or randomness of a system is(entropy, enthalpy, or ...
August 4, 2008 by Blair

CHEMISTRY
NH3(g) + H2O(l) <==> NH4+ (aq) + OH- (aq) a) According to delta H ( Enthalpy ) , which direction the equation will shift ? b) According to Entropy , which direction the equation will shift ? c) Assuming that delta G is positive , then delta S is greater than delta H or ...
July 14, 2014 by MAD

chemistry
Can someone help me with this question? what two conditions must be met by a thermochemical equation so that its standard enthalpy change can be given the symbol delta Hf?
October 12, 2010 by Leslie

Chemistry (Enthalpy)-College
Given that: 2Al(s)+(3/2)O2(g)--->Al2O3(s) change in H(rxn)= -1601 kJ/mol 2Fe(s)+(3/2)O2(g)--->Fe2O3(s) change in H(rxn)= -821 kJ/mol Calculate the standard enthalpy change for the following reaction: 2Al(s)+Fe2O3(s)--->2Fe(s)+Al2O3(s) _______kJ
October 31, 2010 by Lucy

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