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December 20, 2014

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

Number of results: 29,655

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

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
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
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
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

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
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
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
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!! 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

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

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

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
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
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

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
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
You measure Ksp for borax and find it to be 6.2 x 10-3 at 22.8C. 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 is ...
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
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
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

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

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

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
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
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
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

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 (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

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
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
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
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
What are the steps to solve this problem? "The enthalpies of combustion of glucose and ethanol are -2813kj/mol and -1369kj/mol, use Hess's law to calculate the enthalpy change when 0.500 kg of glucose is allowed to ferment." Please help.
November 28, 2014 by Julie

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
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
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
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
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

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
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

Chem
Suppose that the 10.0 g of NH3 is formed in a bomb calorimeter, and that all of the evolved heat for the exothermic reaction is completely absorbed by the surrounding 1000 g of water. Find the change in temperature (ΔT), and the final temperature (TF) of the water if it ...
October 20, 2014 by Feather

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
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

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
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

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

Chemistry due soon
If the following reaction: NO(g) + 1/2O2(g) NO2(g) has the following enthalpy change: H = -56 kJ/mol What is the enthalpy of the decomposition reaction of 2 moles of NO2? A. 112 kJ B. 56 kJ C. -56 kJ D. -112 kJ i think the answer is d
November 7, 2014 by Morgan

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

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

Chem please help
If the following reaction: NO(g) + 1/2O2(g) NO2(g) has the following enthalpy change: H = -56 kJ/mol What is the enthalpy of the decomposition reaction of 2 moles of NO2? A. 112 kJ B. 56 kJ C. -56 kJ D. -112 kJ i think the answer is d
November 7, 2014 by Morgan

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
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

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

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
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(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

Mechanics
A 1-kg ball in the air has an initial velocity vo = [ 20 ] i + [ -30 ] j m/s. It falls for a total time of 1 s. Assume that positive x-values are to the right and positive y-values are upward. A)What is the impulse or change in momentum Delta p of the ball? B)What is the final...
December 5, 2014 by Jo

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
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 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
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
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

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

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

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

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
(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

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

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