Wednesday
September 17, 2014

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

Number of results: 28,387

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
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

chemsitry
c. 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 of formation of gaseous carbon dioxide is -393.5 kJ/mol The ...
October 23, 2010 by Nora

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
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 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
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
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
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
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
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 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

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 (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
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

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
Hydrazine, N2H4, is a colorless liquid used in rocket fuel. What is the enthalpy change for the process in which hydranzine is formed from its elements? N2(g) + H2(g) => N2H4(l) Use the following reactions and enthalpy changes: N2H4 + O2 => 2H2O DeltaH = -622.2KJ H2 + 1/...
September 10, 2008 by Austin

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
1. Nitrogen gas and sodium liquid are produced by the decomposition of sodium azide NaN3 (s). what volume of nitrogen gas, measured at 25 C and 0.980 atm, is produced by the decomposition of 62.5 g of sodium azide? 2. A gas sample in a container with a volume V at a ...
December 9, 2010 by Helen

chemistry
what is the standard enthalpy formation of liquid diethylamine (CH3CH2)2 NH? N2O5(g) + 8CH4(g) ==> 2(CH3CH2)2NH(l) +5H2O(l), delta H= -1103kJ
June 21, 2010 by Ellie

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

Chemistry
HCl(aq) +NaOH(aq) ---> NaCl +H2O In a coffee cup calorimeter 50 ml of 2.00M HCl was combined with 50ml of 2.05M NaOH. a) What is the enthalpy change for the reaction? b) What is the molar enthalpy for the reaction? Given: Change in T= 14 degrees celsius heat capacity of the...
October 8, 2013 by Kuu

Physics
(delta)Eg = -14.7J Therefore, Ek = -(delta)Eg = 14.7J I don't understand how you'd come to the above conclusion? Does Ek just always equal -(delta)Eg?
June 21, 2013 by a Canadian

Chemistry
Nitrogen dioxide, a pollutant in the atmosphere, can combine with water to from nitric acid. One of the possible reactions is shown below. Calculate ∆G0 and Kp for this reaction at 25oC and comment of on the spontaneity of the reaction (MUST plot the data and find ...
April 18, 2013 by Yasemine

Chemsitry
Nitrogen dioxide, a pollutant in the atmosphere, can combine with water to from nitric acid. One of the possible reactions is shown below. Calculate ∆G0 and Kp for this reaction at 25oC and comment of on the spontaneity of the reaction (MUST plot the data and find ...
April 19, 2013 by Yasemine

chemistry
Nitrosyl chloride (NOCl) decomposes at high temperature. The equation is 2 NOCl (g) -> 2 NO (g) + Cl2 (g) at 227C Using delta H = 81.2 kJ and delta S = 128 J/K, calculate the value of the equilibrium constant for this reaction. a 1.60 X 10-2 b. 2.1 X 10-7 c. 62.8 d. 4.9 X ...
April 21, 2012 by CHRIS

chemistry
Nitrosyl chloride (NOCl) decomposes at high temperature. The equation is 2 NOCl (g) -> 2 NO (g) + Cl2 (g) at 227C Using delta H = 81.2 kJ and delta S = 128 J/K, calculate the value of the equilibrium constant for this reaction. a 1.60 X 10-2 b. 2.1 X 10-7 c. 62.8 d. 4.9 X ...
April 21, 2012 by CHRIS

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

Chem
I need to figure out Delta H, Delta S, and Delta G for the following problem. H2+F2 Yeilds 2HF the temperature is at 298K
June 18, 2011 by Stacy

chemistry
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. 1. 69.3 kJ 2. -111 kJ 3. -139 kJ 4. 139 kJ 5. -69.3 kJ help plz
November 19, 2009 by noshi

chemistry
Hydrogen peroxide decomposes according to the following thermochemical reaction H2O2 --> H2O +1/2 O2 ; H= -98.2 kJ calculate the change in enthalpy when 1.00 g of hydrogen peroxide decomposes.
November 20, 2009 by Brittany

Chemistry
Calculate the change in enthalpy when 52.0 g of solid chromium at 25C and 1 atm pressure is oxidized. (Hf for Cr2O3(s) is 1135 kJ/mol.) 4Cr(s) + 3O2(g)  2Cr2O3(s) a. 1135 kJ b. 284 kJ c. 568 kJ d. +1135 kJ e. +568 kJ
July 1, 2013 by Jessica

CHEMISTRY
The enthalpy change of an endothermic reaction is 8 kJ , and this reaction is spontaneous at 25 oC ,, what is the expected entropy change ? thank you a lot
July 6, 2014 by MAD

Chemistry - Enthalpy reactions
What is the reaction enthalpy for CaCO3(s) --> CaO(s) + CO2(g)? should i be using a enthalpy reaction table?
February 29, 2012 by Rose Bud

chemistry
Calculate (delta)Suniv in J/mol-K for the above process at 298.15 K. Again, balance all chemical reactions using the loweset ratio of whole numbers. 1Fe2O3(s) + 3CO(g)--> 2Fe(s) + 3CO2(g) the standard entopy change is 16.4 J/molK
October 2, 2009 by Anonymous

calculus
limit as delta x approaches 0 when f(x) = 4/ sqr x Have to use the (F(x+delta x)-f(x))/delta x method
August 31, 2012 by kale

Chemistry
Estimate the temperature where Delta G = 0 for the following reaction (Given: Delta H=-176 and Delta S = -284.5 J/K NH3 + HCl --> NH4Cl
May 1, 2013 by ramire2

Enthalpy Chemistry
Can someone make sure I did this write! What is the molar change in enthalpy when 100 g of ice is heated from -18.2 C to -72 C (Cp = 37.4 J/K*mol) 100g of ice = 100 g/-18.2 C = 5.56 mol 5.56 mol * 37.4 J/K * mol * 53.8 K = 1118 J
June 7, 2010 by Libby

chemistry
Data: SO2(g) + O2(g) SO3 (g) H = -99.1 kJ Given the above data, calculate the enthalpy change H when 89.6 g of SO2 is converted to SO3.
October 16, 2011 by syd

chemistry
The Clapeyron-Clausisus Equation is ln(P2/P1) = dHvap/R [(1/T1)-(1/T2)]. Assuming that dHvap doesn't change with the temperature, this equation relates the change in vapor pressure and temperature to a substances enthalpy of vaporization (R is the molar gas constant). Use this...
February 18, 2012 by isabelle

Chemistry
Using standard enthalpies information, calculate the standard enthalpy change for this reaction: a) (thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b) Mg(OH)2(s) = MgO(s) + H2O(I) c) N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d) SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)
July 3, 2014 by Brett

Chemistry
Using standard enthalpies information, calculate the standard enthalpy change for this reaction. a)(thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b)Mg(OH)2(s) = MgO(s) + H2O(I) c)N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d)SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)
July 3, 2014 by Dan

chemistry
The following reation has the following standard thermodynamic parameters: delta H= -33.6 kJ/mol delta S= -59.8 J/(mol*K). C(g) + D(g) --> E(g) Calculate the temperature at which the reaction becomes nonspontaneous.
October 5, 2012 by Brunette

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

science
1mole of liquid water at 25 c and 1 atm forms 1 mole of steam at 100 c and 1 atm. the molar heat capacity of water 373 k is 40.79kj/mol and the molar heat capacity of water is 75.3 J. assume ideal gas behavior for steam. Calculate delta U, delta H and delta S
March 29, 2013 by bob

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

Chemistry
BrO-3 + 5Br- + 6H+ ---> 3Br2 + 3H2O the value of - delta[BrO3]/delta T= 1.5x10^-2M/s at a particular time what is the value of -delta [Br-]/Delta t at the same instant? 13 M/s 7.5x10^-2 1.5x10^-2 3.0x10^-2 330 M/s
February 25, 2008 by drew

calculus
Find f(x+ (delta)x)- f(x) --------------------- (delta)x if f(x)=8x(squared)+ 1 This is so confusing! What is all the delta x stuff?
September 18, 2008 by Kim

Chemistry
The following thermodynamic data was obtained for an unknown compound. Delta Hvap = 31.3 kj/mol and Delta S Vap= 79.7 kj/mol .Calculate the normal boiling point of this compound in Celcius.. Thank you!
April 29, 2013 by Chloe

Chemistry practice
Using the form of energy diagram,make a concept map of the two different methods of calculation of reaction enthalpy(via the bond enthalpy and via the enthalpy of formation)
July 31, 2011 by Gift

Chemistry
To obtain the rate of the reaction 3I-(aq) + H3AsO4(aq) + 2H+(aq) --> I3-(aq) + H3AsO3(aq) + H2O (l) I got that the rate is 1/3 delta [I-]/ delta t = delta [H3AsO4]/ delta t is this correct
February 17, 2008 by Lauren

Chemistry
To obtain the rate of the reaction 3I-(aq) + H3AsO4(aq) + 2H+(aq) --> I3-(aq) + H3AsO3(aq) + H2O (l) I got that the rate is 1/3 delta [I-]/ delta t = delta [H3AsO4]/ delta t is this correct
February 17, 2008 by Lauren

Chemistry
To obtain the rate of the reaction 3I-(aq) + H3AsO4(aq) + 2H+(aq) --> I3-(aq) + H3AsO3(aq) + H2O (l) I got that the rate is 1/3 delta [I-]/ delta t = delta [H3AsO4]/ delta t is this correct
February 18, 2008 by Lauren

Chemistry
To obtain the rate of the reaction 3I-(aq) + H3AsO4(aq) + 2H+(aq) --> I3-(aq) + H3AsO3(aq) + H2O (l) I got that the rate is 1/3 delta [I-]/ delta t = delta [H3AsO4]/ delta t is this correct
February 18, 2008 by Lauren

science
the specific heat capacity of lava is 1600 j kg -1 oC -1. when all the erupted lava cools from the eruption temperture of 1050 oC to 15 oC, the heat released is 15 2x10 j. calculate a value for the total mass of lava that erupted. give your answer in scientific notation. The ...
May 16, 2007 by smartypants

Chemistry
50 mL of copper(II) sulfate reacts with 50 mL of sodium hydroxide. Their concentrations are 0.3 M and 0.6 M respectively. The temperature increased to 23.6 C from 23.4 C. Determine the enthalpy change for the reaction in kJ/mol of sodium hydroxide. Q=mcΔT =(50g + 50g)(4....
March 3, 2013 by a Canadian

chemistry
When water freezes, the phase change that occurs is exothermic (DH = -6.02 kJ). Based on the change in enthalpy, you would expect that water would always freeze. Use the concepts of entropy and free energy to explain why this phase change is favourable only below o degrees ...
April 6, 2008 by Sarah

chem question
This is on a practise exam I have and I cant get part of it, I don't know if it is not only due to my not understanding but to the fact that the first two parts might be wrong. Thanks for your help if you can. Heres the question: A coffee-cup calorimeter normally consists of ...
June 20, 2006 by Natalie

Physics
The bulk modulus of water is B = 2.2 x 10^9 N/m2. What change in pressure Delta P (in atmospheres) is required to keep water from expanding when it is heated from 12.4 C to 31.1 C? I know that the equation for pressure is Delta P = Force / Area but I have no idea what I have...
April 21, 2014 by Kace

Chemistry
Calculate the amount of heat released in the complete combustion of 8.17 grams of Al to from Al2O3 at 25 celcius and 1 atm. The delta enthalphy change in the heat of formation for Al2O3 = 1676 KJ/mol 4Al(s) + 3O2(g) --> 2Al2O3(s)
April 16, 2012 by Philip

Physics
It is reasonable to assume that the bulk modulus of blood is about the same as that of water (2.20 GPa). As one goes deeper and deeper in the ocean, the pressure increases by 1.0*10^4 Pa for every meter below the surface. If a diver goes down 33.0 m (a bit over 100 ft) in the ...
November 14, 2007 by Christina

Physics
It is reasonable to assume that the bulk modulus of blood is about the same as that of water (2.20 GPa). As one goes deeper and deeper in the ocean, the pressure increases by 1.0*10^4 Pa for every meter below the surface. If a diver goes down 33.0 m (a bit over 100 ft) in the ...
November 14, 2007 by Marie

science
hi guys I really need some help with my homework its so confusing here it is. 5.00g of glucose,C6H12O6, is dissolved in 500g of acetic acid. What is the new freezing point and boiling point for the solution? Kf,acetic acid = 3.90 Kb,acetic acid = 3.07 (normal freezing point ...
March 24, 2007 by stacy

Chemistry
(1) Why are fractional coefficients permitted in a balanced thermochemical equation? In thermochemical reactions, only small amounts of matter are considered. If fractional coefficients were not used, the scale of the reaction would be excessively large. Fractional ...
May 12, 2010 by Zacky

chemistry
The change in internal energy for the combustion of 1.0 mol of octane at a pressure of 1.0 atm is 5084.3kJ. if the change is enthalpy is 5074.1kJ, how much work is done during the combustion?
February 20, 2011 by Anonymous

Chemistry
4Fe + 3O2 -> 2Fe2O3 + 1.65E3 kJ C) what is the enthalpy change for the formation of 23.6 g of iron(iii) oxide? I'm trying to understand thermochemical reactions and stoichiometry, so could you please tell me if this is correct? And please explain the parts that I clearly ...
February 6, 2013 by A Canadian

Chemistry
4Fe + 3O2 -> 2Fe2O3 + 1.65E3 kJ C) what is the enthalpy change for the formation of 23.6 g of iron(iii) oxide? I'm trying to understand thermochemical reactions and stoichiometry, so could you please tell me if this is correct? And please explain the parts that I clearly...
February 6, 2013 by A Canadian

differentiation
by determining : lim f(x+h)-f(x) h->0 --------------- h show that if f(x)=2x^2+2 then dy/dx=4x. i figured out that f'(x) is 4x...but i am confused about what to do next...someone help? "i figured out that f'(x) is 4x..." That's the answer! dy/dx is just a notation for the ...
May 25, 2007 by Emma

Chemistry(Please help)
1) Nitrosyl chloride (NOCl) decomposes at high temperature. The equation is 2 NOCl (g) -> 2 NO (g) + Cl2 (g) at 227oC Using delta Ho = 81.2 kJ and delta So = 128 J/K, calculate the value of the equilibrium constant for this reaction. I do not know how to start this problem ...
April 23, 2012 by Hannah

chemistry
consider the following changes at constant temperature & pressure H2O(s) --yields-- H20(l); Delta H1 H2O(l) --yields-- H2O(g); Delta H2 H2O(g) --yields-- H2O(s); Delta H3 Using Hess's law, the sum of the deltas is a. equal to 0 b. sometimes greater than zero, sometimes less ...
November 14, 2012 by marcus

Chemisty-Freezing Points
The freezing point of benzene is 5.5C. What is the freezing point of a solution of 8.50 g of naphthalene (C10H8) in 425 g of benzene (Kf of benzene = 4.90C/m)? delta T = Kf m m = mols/kg solvent. Change 8.5 g naphthalene to mols and 425 g benzene to kg. That will get delta T...
January 21, 2007 by Swim4eva

chmistry
3O2(g)---> 2O3(g) Delta H = +284.6 kJ what is the sign of delta G and delta S
February 5, 2013 by bb

Chemistry
Explain the significance of positive and negative values for each thermodynamic quantity in the free energy equation. (enthalpy change, entropy change, and free energy change) I think this is something you can find in your text/notes. If not, explain what you don't understand ...
May 14, 2007 by Dave

chemistry
Under the appropriate conditions, NO forms NO2 and N2O: 3NO(g) <--> N2O(g) + NO2(g) Use the values for delta G naught for the following reactions to calculate the value of Kp for the above reaction at 500.0 C 2NO(g) + O2(g) <--> 2NO(g) delta g=-69.7 kJ 2N2O(g) <...
November 5, 2012 by Victoria

chemistry
I have to find delta G from a problem. Not the standard free energy, from the change in engery. So this delta G does not have the degree sign above. The equation i used was deltaG=standard G+RTlnQ If deltaG was a positve number, what does that tell me. I know that if the ...
March 1, 2009 by Anonymous

chemistry
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
For the reaction shown below complete the following calculations. H2(g) + C2H4(g) --> C2H6(g) (a) Estimate the enthalpy of reaction using the bond energy values in Table 9.4. (b) Calculate the enthalpy of reaction, using standard enthalpies of formation. (ΔHf for H2, ...
October 27, 2008 by hannah

chem
Calculate the standard enthalpy change for the reaction 2A+B->2C+D Use the following data: Substance A=-257kj/mol B=-413kj/mol C=189kj/mol D=-475kj/mol For the reaction given , how much heat is absorbed when 3.00mol of A react?
October 8, 2008 by tomi

chemistry
In the experiment you have added 50.0 mL of Ni(H2O)6 2+ to the calorimeter. To this you add 5.0 mL of ethlylenediamine and measure the change in temperature of the solution as the reaction proceeds. The temperature increases by 3.4 oC. Calculate the enthalpy (H) for ...
April 9, 2013 by Barb

Chemistry
Mg + 2HCl -> MgCl2 +H2 delta H = ? MgO + 2HCl (aq) -> MgCl2+ H2O delta H = ? H2+ 1/2O2 -> H2O delta H = -285.8 kJ Using Hess' Law find both the missing delta H values.
March 28, 2012 by Hunter

Chemistry
Hi I need help with these following questions. I have all of the data needed. Calculate the enthalpy change of the reaction for each trial (in kJ) 3. Calculate the heat released by the reaction for each trial (in J): 2. Calculate the heat absorbed by the calorimeter for each ...
November 17, 2013 by Matt

Chemistry
I would really appreciate some help with this thermochemistry problem! I'm really confused as to why I keep getting the wrong answers... I have gotten w=-1.305kj and energy change = 78.13kj... both of which were marked wrong. Here's the question: The oxidation of copper(I) ...
November 3, 2013 by DC

Re: Physics/Math
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 24, 2007 by winterWx

Chemistry
One more problem with 1/2 reactions Pb(s) + PbO2(s) + 2H2SO4(aq)->2PbSO4(aq)+2H2O(l). How do you split them up with two Pb solids on the same side of the equation? Again you need to identify what is being reduced and what is being oxidised. I think I read the question wrong...
April 19, 2007 by amy

physics help!!!
the volume occupied by 1kg of water at 100C and atmospheric pressure changes from 1L in the liquid phase to 1700L in the vapor phase. evaluate the difference in internal energy of 1kg of water vapor and 1kg of liquid water at the normal boiling point: So i have the equation is...
June 24, 2009 by sarah

Chemistry/stoichiometry
If you can do just one for me I can used it as a template to do the rest. Thank you in advance For each reaction, calculate the mass (in grams) of the product formed when 10.3 of the underlined reactant completely reacts. Assume that there is more than enough of the other ...
October 26, 2012 by Dale

chemistry
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. 1. 69.3 kJ 2. -111 kJ 3. -139 kJ 4. 139 kJ 5. -69.3 kJ i got -139 kj but im so unsure may some one confirm it for me?
November 24, 2009 by paneet

chemistry
c= q/m*(delta)T q= heat or energy, measured in joules (J) c= specific heat of the substance m= mass of substance (delta)T= change in temperature It requires 14,749 J to heat 75.0 g of water from 20.0 degrees C to 67.0 degrees C?
September 9, 2012 by waffles

Chem, LAST ONE PLEASE HELP!
consider the reaction: CO(aq) + Cl2 (aq) --> COCl2 (aq). Calculate Delta G at non standard conditions. T = 298.15K. Concentration of COCl2 is reduced to 0.01832 M while the concentrations of CO and Cl2 remain 1M. Delta G rxn = -67.4 kj.
November 24, 2010 by Tara

Chemistry
Use Hess's law to calculate the enthalpy change for the reaction: 3C(s) + 3H2(g) C3H6(g) Given the following thermochemical equations: 2C3H6(g) + 9O2(g) 6CO2(g) + 6H2O(l) H = -4116.0 kJ/mol C(s) + O2(g) CO2(g) H = -393.51 kJ/mol H2(g) + O2(g) H2O(l) H = -...
March 16, 2012 by Hailee

chemistry
For a certain change, value of Delta U is -2.37 kJ. During the change, the system absorbs 650 joules. How much work did the system do? Please help! I get 3.02 but is not correct!!
March 1, 2013 by Mary

Chemistry
I'm working on a problem dealing with calculating the heat of vaporization for vapor pressures problem. By substituting the problems values into the Clausuis-Clapeyron equation I get: .642= (2.28x10-5) x Delta H vap (J/mol) However, from this point I don't know how to ...
March 11, 2013 by Marcus

Teddy
f(x,y) = 3x + 3y Show that for any epsilon in: |2x + 3y - 5| < epsilon There is a delta value: sqrt((x - 1)^2 + (y - 1)^2) < delta Solve for delta in terms of epsilon ------ I understand that this is a proof that the limit of f(x,y) as (x,y) -> (1,1) is 5. But I'm ...
January 24, 2013 by calculus

Chemistry
At 298K and 1bar pressure, the density of water is 1.00 g/cm^3 , Cpm = and 75.3 J/Kmol. The change in volume with temperature is given by delta V = ViB(deltaT), where B, the coefficient of thermal expansion, is 2.07 * 10^-4 K^-1. If the temperature of 350g of water is ...
September 24, 2012 by Danielle

A.P. Economics
1. Marginal is the change in one variable due to a unit change in another. For example, the change in the X value from 2 to 3 is 1 or a "unit change", which leads to an increase in Y from 12 to 21 or a "marginal increase" in the Y value of 9. The symbol Δ (the Greek ...
December 22, 2010 by Namchi

Chemistry
use the data from this table of thermodynamic properties to calculate the maximum amount of work that can be obtained from the combustion of 1.00 moles of ethane, CH3CH3(g), at 25 C and standard conditions. on the chart is said ethane(C2H6) is -84.0. In the hint it said ...
April 28, 2014 by Alexis

Pages: <<Prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | Next>>

Search
Members