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September 21, 2014

Search: A reaction has deltaHrxn=-127 kJ and delta S rxn=314 J/K. At what temperature is the

Number of results: 19,032

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

CHEMISTRY
You carry out a reaction with 28.9mL of 0.711M solution of NiNO3)2. The reaction has a change in H of -26.4KJ/mol rxn. What is the q, the heat of the reaction, in joules? I first found the mols of the solution using molarity and then found the joules of the reaction through ...
April 23, 2013 by markymark

chemistry
I originally used 1 gram of NaOH. What if I used 2 grams of NaOH. Would that change the heat evolved, Q and change in ethalpy, (delta)H? Through direct calculation, I see that the Q change by only about 0.1 kcal, but for (delta)H, I see that the value halved(which is expected ...
July 18, 2008 by Anonymous

chemistry
Thermite mixtures are used for certain types of weldings and the thermite reaction is highly exothermic. Given delta H= -852 KJ/mol, 1 mole of granular Fe2O3 and 2 moles of granular aluminum are mixed at room temperature and the reaction is initiated. the liberated heat is ...
July 27, 2013 by sharmaine

chemistry
Thermite mixtures are used for certain types of weldings and the thermite reaction is highly exothermic. Given delta H= -852 KJ/mol, 1 mole of granular Fe2O3 and 2 moles of granular aluminum are mixed at room temperature and the reaction is initiated. the liberated heat is ...
July 27, 2013 by sharmaine

chemistry
Assume that a particular reaction evolves 241 of heat and that 25 of work is gained by the system. What are the values of delta E and delta H for the system?
December 10, 2012 by LaK

Chem
Does adding a catalyst to a rxn mixture add energy that causes the rxn to proceed more quickly. I answered: No, a catalyst simply lowers the activation energy by providing an alternate route to the desired product allowing the rxn to speed up. Does that make sense? Anything I ...
February 21, 2008 by Anonymous

Physics please check
Please tell me where i went wrong. During an all-night cram session, a student heats up a one-half liter (0.50 10-3 m3) glass (Pyrex) beaker of cold coffee. Initially, the temperature is 19C, and the beaker is filled to the brim. A short time later when the student returns, ...
April 13, 2007 by Mary

stat mech
how to solve this problem 3. Five moles of an ideal monatomic gas with an initial temperature of 127 C expand and, in the process, absorb 1200 J of heat and do 2100 J of work. What is the final temperature of the gas?
June 23, 2014 by acinad

Chemistry
Assume that a particular reaction evolves 230 kJ of heat and that 28 kJ of PV work is gained by the system. What are the values of delta E and delta H for the system? For the surroundings?
December 6, 2012 by Thalia

Chemistry
A 2.75 g sample of the hydrocarbon acetone, CH3COCH3, is burned in a bomb calorimeter with 975 mL of water, initially at 23.50 degrees celsius. The bomb is constructed of 285.0 g of nickel metal having a specific heat capacity of Cp = 0.826 J/ g degrees C. The final ...
September 30, 2007 by Kate

Chemistry
A 2.75 g sample of the hydrocarbon acetone, CH3COCH3, is burned in a bomb calorimeter with 975 mL of water, initially at 23.50 degrees celsius. The bomb is constructed of 285.0 g of nickel metal having a specific heat capacity of Cp = 0.826 J/ g degrees C. The final ...
September 30, 2007 by Kate

Chemistry
When 0.643 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 105C is observed. Assume the solution's final volume is 200.0 mL, the density is 1.00 g/mL, and the heat capacity is 4.184 J/gC. (Note: Pay attention to significant figures. Do not ...
May 7, 2007 by Jared

chemistry
The following reaction is at equilibrium at a pressure of 1 atm, in a closed container. NaOH(s) + CO2(g) NaHCO3(s); ΔHrxn < 0 Which, if any, of the following actions will decrease the concentration of CO2 gas present at equilibrium? A. lowering the temperature B. ...
April 23, 2010 by bme1

Chemistry(Please check)
1)A piece of metal with a mass of 5.50 grams changed in temperature from 25 to 55 degrees celsius when 21.3 joules was absorbed. What is the specific heat of the metal? a)0.256 b)0.129 c)3.91 d) 7.75 e)0.710 Jg^-1 C^-1 I chose 7.75 because I did 5.50/21.3 and then multiplied ...
January 20, 2012 by Hannah

chem
stilll didnt 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

Physical Chemistry
When the reaction glucose-1-phosphate (aq) --> glucose-6-phosphate (aq) is at equilibrium at 25.0 degrees celcius, the amount of glucose-6-phosphate present is 95% of the total. A.) Calculate the Standard Delta G at 25.0 degrees celcius. B.) Calculate Delta G for the ...
October 20, 2006 by Angela

ap chemistry
Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction: 2CO2 + O2 yields 2CO2 Delta H for this reaction is -566 kJ/mol run. What is the delta H for CO? 1). +270 kJ/mol 2). -110 kJ/mol 3). +65 kJ/mol 4). -405 kJ/mol 5). -65 kJ/mol 6). -182 kJ/mol 7...
October 18, 2012 by bridget

Calc
The temperature of a chemical reaction, t seconds after the reaction starts, is given by: T(t)= 20+5.25t^.75 degrees F , What is the average temperature during the whole process, if the reaction lasts for 4 minutes and 16 seconds ?
February 9, 2014 by Rebekah

Chemistry
Consider the reaction 2 SO2 + O2 in equilibrium with 2 SO3 . At 25C Ho = -197.78 kJ and So = -187.95 J/K. Using this information, calculate the equilibrium constant for the reaction at 50C. (R = 8.314 J/K) Enter your answer using TWO significant figures.
April 6, 2011 by Laura

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

Chemistry :(
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 PLEASE EXPLAIN IM SOOO ...
October 31, 2010 by Lucy

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
Can you check my calculations, please? It's for a lab we did in order to find the the enthalpy of formation of NH4Cl(s). My final answer was -299.4 kJ, while the theoretical, or actual, value is -314.4 kJ. It was the closest value out of everyone in the entire class. I'm not ...
February 20, 2013 by a Canadian

chemistry 30
Consider the following reaction: 2NO(g)+O2(g)-->2 NO2(g)+ energy if the number of moles of oxygen is increased to two moles, the a. reaction speeds up b. reaction slows down c. temperature increases d. temperature decreases
December 30, 2011 by Tucker

Chemistry-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

Chemistry
A calorimeter contains 22.0 mL of water at 14.0 C. When 2.50 g of X (a substance with a molar mass of 66.0 g/mol) is added, it dissolves via the reaction X(s)+H_2O(l)--------> X(aq) and the temperature of the solution increases to 25.5 C. Calculate the enthalpy change, ...
April 2, 2012 by Amanda

chemistry
Calculate the temperature at which it is thermodynamically possible for C (s) to reduce iron(III) oxide by the reaction: 2Fe2O3 (s) + 3 C (s) ---> 4Fe (s) + 3CO2 I don't need a specific answer, but I'm not sure how to approach the problem. I'm assuming it has to do with ...
February 28, 2013 by Janet

chemistry
What effect (shift to the right or left) does an increase in temperature have on each of the following systems at equilibrium? a) 3O2(g) ==> 2O3 (g) <== Delta H = 284 KJ b) 2SO3(g) + O2(g) ==> 2SO3(g) <== Delta H = -198.2 KJ
June 15, 2010 by kyle

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
In general, reaction rates double when the temperature is increased by 10C. The temperature of a reaction is increased by 40C. The rate of the reaction will increase by a factor of ____? is it 16?
January 9, 2011 by tycoon

Chemistry
Could someone explain Le Chatelier's principle to me? Thanks Reactions tend to go to the direction that reduces stress: stress from pressure, temperature. If a reaction gives off heat (exothermic), it will go faster if temperature is reduced, ie, it is easier to give off heat ...
March 15, 2007 by Aubrey

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

Chemistry
The four statements below are used for applications of Hess's law. One of the statements is erroneous. Choose that statement. a) the value of delta H for any reaction that can be written in steps is the sum of the values of delta H for each of the individual steps. b) when an ...
January 20, 2012 by Hannah

Physics
I got part a and b, but not c. We are trying to find delta T in part c, but I'm still confused on where to start even with the help. (a) An iron block of the mass 1.2 kg is suspended on a spring of the spring constant 140 N/m, and merged into a vessel with 5 liters of water. ...
December 3, 2010 by Susan

Chemistry
The following standard free energies are given for 25 degrees celcius. 1) N2(g) + 3H2(g)-> 2NH3(g) delta g = -33.0 kJ 2) 4NH3(g) + 5O2(g)-> 4NO(g) + 6H20() delta g = -1010.5 kJ 3) N2(g) + o2(g)-> 2NO(g) delta g = 173.1kJ 4) N2(g) + 2O2(g) -> 2NO2(g) delta g = 102.6...
July 6, 2011 by K

Chemisty - Unsure how to proceed- Combustion rxn
Question as follows: If you combusted 23g of ethanol with an excess of oxygen how much heat would be released or absorbed? the only thing I've deduced is the chemical reaction: C2H6O + 302 -> 3H20 + 2C02 I'm not sure how to proceed. I need Q. Not sure which equation to use ...
March 21, 2014 by Angely R.

CHEMISTRY!! NEED IMMEDIATE HELP PLEASE!!!
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

moles of water produced?
We mixed HCl and NaOH into water and got this table, all for trial 1 Here is all of the info for trial 1: trial 1: volume of 2 M NaOH used: 50.0 mL initial temperature of NaOH: 24.4 degrees C volume of 2 M HCl used: 50.0 mL initial temperature of HCl: 24.3 degrees C final ...
March 12, 2010 by Abdullah

Chemistry(Please help)
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 didnt give me the correct answer. Chemistry(Please help) - Dev, Wednesday, April 25, 2012 at 6:56pm ...
April 28, 2012 by Hannah

AP CHEMISTRY!!!!
Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction: 2 CO(g) + O2(g) → 2 CO2(g) ∆H for this reaction is −566 kJ/mol rxn. What is the ∆H for CO(g)?
October 18, 2012 by Joe King

chem
For the gaseous equilibrium represented below, it is observed that greater amounts of PCl3 and Cl2 are produced as the temperature is increased. PCl5(g) <===> PCl3(g) + Cl2(g) a) What is the sign of S for the reaction? Explain. b) What change, if any, will occur in G ...
April 29, 2008 by Luke

reaction rate help
In general, reaction rates double when the temperature is increased by 10C. The temperature of a reaction is increased by 40C. The rate of the reaction will increase by a factor of ____? is it 16?
January 9, 2011 by tycoon

Chemistry
Consider the reaction Zn(OH)2(s) + 2CN-(aq) <--> Zn(CN)2(s) + 2OH-(aq) a) Calculate K for the reaction. (Ksp Zn(CN)2= 8.0 x 10^-12) b) Will Zn(CN)2 precipitate if NaCN is added to a saturated Zn(OH)2 solution? I tried splitting this into two equations: Zn(OH)2(s)<--&...
April 11, 2007 by Kristina

Chemistry (11th)
When A + B --> C then this reaction occurs in water, heat is given off. 1) Will the temperature of water go up or go down ? - is the asnwer down ? since the energy is released to the surrounding. 2) What is the sign for delta H ? + or - ?
September 11, 2010 by Anonymous

chemistry
Calculate Kp at 298 K and 490 K for the reaction NO(g) + 1/2 O2(g) = NO2(g) assuming that Delta H(g) is constant over the interval 298 K - 600 K. Do you expect Kp to increase or decrease as the temperature is increased to 600 K?
April 7, 2013 by hayley

chemistry
For the following fusion reaction, Calculate change in energy per mole.( Answer in J/mole) 2H1 + 2H1 ---> 3H1 + 1H1 (the mass number is in front of the atom and the atomic number is behind the atom) Given info:Atoms with their masses(amu) H-1 1.00782 H-2 2.01410 H-3 3.01605...
April 28, 2012 by Mima

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
The water gas shift reaction used commercially to produce H2(g): CO (g)+ H2O (g) --> CO2 (g) + H2(g). DeltaH=-41.2 kJ/mol Delta S= -42.1 J/mol*K Delta G= -28.6 kJ\mol Determine Kp at 850 K
December 2, 2012 by Allyx3

Urgent Chem help plz
is answer +103 KJ.. plz chk 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...
November 12, 2008 by Sarah

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

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

CHEMISTRY
Method for getting correct answer? Thank you! The reaction below is an endothermic reaction. What would one have to do to shift the equilibrium to the right? SO2Cl2(g)↔SO2(g) + Cl2(g) a. Decrease the temperature b. Increase the temperature c. Remove some reactant d. An ...
April 6, 2014 by Chemistry

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
Temperature Rate Constant 310 0.830 320 2.27 330 5.83 340 14.2 350 32.8 Use an Arrhenius plot to determine the frequency factor for the reaction. I know the equation to find the frequency factor is K= Ae^-Ea/RT but i am still getting the wrong answer. Do I convert the ...
September 19, 2011 by Tc

chemistry
A mass of 2g of magnesium wire is oxidized with 150 ml of 0.5 mole/l (HCL solution) write the half rxn and the balanced equation of the overall rxn
October 16, 2010 by Anonymous

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

Chemistry
A gas is allowed to expand at constant temperature from a volume of 2.00 L to 11.20 L against an external pressure of 1.500 atm. If the gas loses 256 J of heat to the surroundings, what are the values of q, w, and ΔU? Pay careful attention to units. -----My attempt: q = ...
October 9, 2012 by Syed

Chemistry
A gas is allowed to expand at constant temperature from a volume of 2.00 L to 11.20 L against an external pressure of 1.500 atm. If the gas loses 256 J of heat to the surroundings, what are the values of q, w, and ΔU? Pay careful attention to units. -----My attempt: q = ...
October 9, 2012 by Syed

Chem, help please
Consider the reaction N2 + 3H2 in equilibrium with 2 NH3 . At 25C Ho = -92.22 kJ and So = -198.53 J/K. Using this information, calculate the equilibrium constant for the reaction at 226C. (R = 8.314 J/K) Enter your answer using TWO significant figures. You may use scientific...
November 19, 2010 by Shayne

CALCULUS help please
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

CHEMISTRY
During an experiment, a student adds 1.23 g of CaO to 200.0 mL of 0.500 M HCl. The student observes a temperature increase of 5.10 C. Assuming the solution\'s final volume is 200.0 mL, the density if 1.00 g/mL, and the heat capacity is 4.184 J/(gC), calculate the heat of ...
June 26, 2013 by imstupid

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 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
A calorimeter contains 21.0 mL of water at 14.0 degreesC. When 1.90 g of X (a substance with a molar mass of 70.0 g/mol) is added, it dissolves via the reaction X(s)+H_2O(l)reacts to make X(aq) and the temperature of the solution increases to 28.5degreesC. Calculate the ...
October 22, 2010 by Ellen

Chemistry
When a vehicle is parked in the sunlight on a hot summer day, the temperature inside can approach 55 deg C. one company has patented a non-CFC propelled aerosol that can be sprayed inside a vehicle to reduce the temperature to 25 deg C within seconds. the spray contains a ...
November 20, 2010 by Rayana

Chemistry
When a vehicle is parked in the sunlight on a hot summer day, the temperature inside can approach 55 deg C. one company has patented a non-CFC propelled aerosol that can be sprayed inside a vehicle to reduce the temperature to 25 deg C within seconds. the spray contains a ...
November 21, 2010 by Rayana

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

College Chemistry
The molar heat of reaction, H rxn, for the reaction of Ca(s) + 2H+(aq) Ca2+(aq) + H2(g) is -544.789 kJ/mol and Hrxn, for the reaction of CaO(s) + 2H+(aq) Ca2+(aq) + H2O(l) is -192.42 kJ/mol, the heat of formation of water is -286 kJ/mol, The H ffor CaO(s) is _____ kJ/mol. ...
February 18, 2011 by HELP PLEASE!

ap chemistry
Some reactions that are predicted by their sign deltaG to be spontaneous at room temperature do not proceed at a measurable rate at room temperature. A suitable catalyst increases the rate of such a reaction. What effect does the catalyst have on deltaG for the reaction? AND ...
February 27, 2008 by kali

calculus
correct me if I'm wrong please. 1. What is the value of Lim 2x+3/4x-5 when x>00 (infinity?) a.-3/5 b.0 c.1/2 <.. my answer d.1 2. An object moves according to the law s = t^2 + 5t - 8. What is the average rate of change of s with respect to t in the interval t to (t + ...
February 6, 2011 by Anonymous

chemistry
to calculate Ea i solved for slope and i got -7.6111x10^3 so i did this for Ea: 7.61x10^3 x 8.314/mole= 63.3 KJ/Mol but someone told me im missing the number 2.30? that i have to mulitply (2.30)(8.314)(7.61x10^3)=? which is right?
October 24, 2010 by ben

chemistry
to calculate Ea i solved for slope and i got -7.6111x10^3 so i did this for Ea: 7.61x10^3 x 8.314/mole= 63.3 KJ/Mol but someone told me im missing the number 2.30? that i have to mulitply (2.30)(8.314)(7.61x10^3)=? which is right?
October 24, 2010 by ben

temperature change
What is the temperature change when 9.8 g of KNO3( with 34.9 kJ/mol enthaply of solution) is dissolved in 150 g of water? Assume that the specific heat capacity is 4.18 J/K*g. Answer in celcius. So far I have the Q= ^T*m*s but i don't know what numbers go where and what not. ^...
May 29, 2007 by ty

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
Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g) delta H1? MgO(s) + 2HCl(aq) ->MgCl2(aq) + H2O(l) delta H2? To make these equations add up to the formation reaction of MgO, you will need to include the following: H2(g) + 1/2O2(l) delta H =-241.8 kJ Using Hess's Law and manipulating...
February 14, 2012 by Hannah

Chemistry
How much heat (in kilojoules) is released on reaction of 4.10 g of Al? Reaction: 2Al(s) + 3Cl2(g)--->2AlCl3(s) Delta H= -1408.4 KJ
February 16, 2010 by Jackie

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(Please help)
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 didnt give me the correct answer.
April 25, 2012 by Hannah

Chemistry
When 0.250 mol of CH4(g) reacts with excess Cl2(g) at constant pressure according to the chemical equation shown below, 177 kJ of heat are released. Calculate the value of Delta H for this reaction, as written. 2CH4(g)+3Cl2(g)-->2CHCl3(l)+3H2(g) delta H=?
March 18, 2010 by Daqa

Chemistry
A particular reaction has an activation energy of 51.6 kJ/mol-rxn. How much faster is the reaction at 50 oC versus 25 oC? a. 2 times b. 5 times c. 3 times d. half as fast d. 20% as fast I think it would be A??
February 23, 2012 by Mohamed

chemistry
My chem book gives me the following Hess' Law example: Mg + 2HCl --> H2 MgCl2 Delta H1 MgO +2HCl --> H2O +MgCl2 Delta H2 H2 + 1/2 O2 --> H2O Delta H3=-68.3kcal The desired reaction is the formation reaction of MgO as follows: MgS +1/2 O2 --> MgO Delta H final= ...
December 6, 2012 by marcus

Chemistry
Delta H reaction for the following reaction: C(s)+H2O(g)=>CO(g)+H2(g)
October 23, 2011 by Chris

Chemistry
According to the following reaction, how much energy is evolved during the reaction of 32.5g B2H6 and 72.5g Cl2? The molar mass of B2H6 is 27.67g/mol. B2H6(g)+6Cl2(g)----->2BCl3(g)+HCl(g) Delta H reaction=-1396
April 2, 2012 by Amanda

chemistry
Consider the following reaction: 2 NO(g) + O2(g) ---> 2 NO2(g) + energy if the number of moles of oxygen is increased to two moles, the a. reaction speeds up b. reaction slows down c. temperature increases d. temperature decreases I'm not really sure what the answer to this...
February 21, 2012 by Aria

Chemistry
Which of the following would involve the largest production of heat per mole? a)the burning of gasoline b)the evaporation of water c)the fission of uranium d)the freezing of water e)the rusting of iron Is it C) Which of the following would involve the greatest absorption of ...
July 23, 2010 by Christian

Chemistry
Calculate ΔHrxn for the reaction 3 O2(g) ==> 2 O3(g) This is the information I am given: 2H2S(g) + SO2g) ==> 3S(s) + 2H2O(l)
December 10, 2008 by Chris

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

Algebra- is my answer right
Charlie is going to rent a truck for one day. There are two companies he can choose from, and they have the following prices. Company A charges $127 and allows unlimited mileage. Company B has an initial fee of $55.00 and charges an additional $0.90 for every mile driven. For ...
February 5, 2011 by Rachal

Chemistry (Equilibrium)
Given the reaction below 2NOBr(g) <==> 2NO(g) + Br2(g) and the value of Kc = 1.98, at a temperature of 480 K what is the value of Kp ? (Hint: Use the value of R in the appropriate units.) I used the equation Kp=Kc(RT)^Delta N Then plugged in to get Kp=1.98(.0821x480k)^-1...
December 9, 2011 by Summer

Chemistry
For the following electrochemical cell, Co(s)/Co2(aq,.0155M)// Ag+(aq,2.50M)/Ag(s) 1.Write the net cell equation. 2.Calculate the following values at 25 degrees celcius. Eocell, Ecell, deltaGo rxn, and delta Grxn
July 25, 2013 by Brianna

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

chem
calculate the delta Hf of c6h12o6 (s) from the following data: Delta H combustion= -2816 kj/mol delta Hf of Co2 = -393.5 kj/mol delta Hf= of H2 O= -285.9kj/mol
March 4, 2012 by Cece

Physics
A2.0-kg piece of steel with a temperature of 70 degree C is submerged in 1.0 kg of water at 15 degree C. At what temperature does the water/metal system reach equilibrium? The specific heat of steel is 0.107 cal/(g*K). Specific Heat of water is 4185 J/(kg*K.( The answer is 27 ...
July 1, 2012 by AL

chemistry
A metal sample weighing 45.0 g and at a temperature of 99.1 degrees Celsius was placed in 38.6 g of water in a calorimeter at 25.0 degrees Celsius. The calorimeter reached a maximum temperature of 32.8 degrees Celsius. what was the delta t of water? what was delta t of metal? ...
November 18, 2010 by Anonymous

AP Chemistry
1) Calculate the volume of air at 30 degrees C and 1.00 atm that is needed to burn completely 10.0 grams of propane. Assume that air is 21.0 percent O2 by volume. 2) Assuming all of the heat evolved in burning 30.0 g of propane is transferred to 8.00 kg of water (specific heat...
October 29, 2006 by OhGodChemistry

Chemistry
Given the following heats of combustion. CH3OH(l) + 3/2 O2(g) CO2(g) + 2 H2O(l) ΔHrxn = -726.4 kJ C(graphite) + O2(g) CO2(g) ΔHrxn = -393.5 kJ H2(g) + 1/2 O2(g) H2O(l) ΔHrxn = -285.8 kJ Calculate the enthalpy of formation of methanol (CH3OH) from its elements...
September 18, 2011 by Ellie

college chemistry
The voltaic cell described by the balanced chemical reaction has a standard emf of 4.05 V. Calculate the equilibrium constant (Kc) for the reaction at 25 oC. Round your answer to 3 significant figures. F2(g) + Mn(s) → 2F-(aq) + Mn2+(aq) Mn2+/Mn -1.18 F2/F- +2.87 0 C = ...
December 2, 2010 by sparkle

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