Friday

April 18, 2014

April 18, 2014

Number of results: 43,843

**Chemistry**

Use standards entropies and heats of formation to calculate delta Gf at 25C for a. cadmium (II) chloride (s) b. methyl alcohol, CH3OH (l) c. copper (I) sulfide (s) I really have no idea where to start with this problem. I have no idea how to calculate delta Gf, and everything ...
*Saturday, November 9, 2013 at 7:41pm by Olivia*

**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...
*Tuesday, February 14, 2012 at 10:16am by Hannah*

**Physics**

delta x = .05 * 10^-9 m m = mass of electron delta p = mass of electron * delta v delta x * delta p = hbar/2 delta x * m * delta v = h bar/2 delta v = hbar/(delta x * 2 * m electron)
*Saturday, February 8, 2014 at 4:15pm by Damon*

**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)
*Sunday, July 31, 2011 at 2:01pm by Gift*

**Chemistry**

I need to calculate the value of Kp at 25 degrees celsius using the delta Go value. Delta Go = -29.10kJ I know that Delta Go = -RT lnK and that R=8.314e-3kJ/K mol -delta Go / RT I did -29.10 / 8.314e-3 X 298K and -11.74 but this was wrong. I am stuck. What did I do wrong?
*Monday, April 23, 2012 at 6:01pm by Hannah*

**Physics**

The liear expansion coefficient for steel in that temperature range is ab9out 12*10^-6 per degree C change. Solve this equation for L: (delta L) = 0.52 m = L*(alpha)*(delta T) where delta T = 30 - 2 = 28 C L = 0.52 m/{28 * 12*10^-6)
*Saturday, April 5, 2008 at 3:27am by drwls*

**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
*Saturday, July 3, 2010 at 11:00am by Car*

**Chem**

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 enthalpy delta H (rxn) of the following reaction: 2SF4 + O2 ---- 2OSF4 Express your answer numerically...
*Wednesday, November 12, 2008 at 11:27pm by Dr BOB plz ANSWER*

**PHYSICAL SCIENCE**

(1/2)MV^2 = M C (delta T) Solve for the temperaure change: delta T. C is the specific heat of the metal head. M cancels out and is not needed. delta T = V^2/(2 C) C should have units of Joules/(kg C). Use a C value for stainless steel. They should have told you what the ...
*Friday, November 2, 2007 at 9:20pm by drwls*

**physics**

The change in internal energy (U) is equal to heat in (Q) minus work out (W). The key to this probloem is knowing that the internal energy per mole of a MONATOMIC gas is (3/2) R T. Thus, delta Q = (3/2)*n* R*(delta T) = 1300 - 2040 = -740 J n is the number of moles and R = 8....
*Sunday, October 4, 2009 at 2:13am by drwls*

**chemistry**

delta Hrxn = (delta H products)-(delta H reactants) delta H products = 3*CO2 + 2*H2O delta H reactants = X delta H rxn given.
*Thursday, December 2, 2010 at 3:48pm by DrBob222*

**general chemistry**

A sample consisting of 0.025 mol of a solid compound is placed inside a metal cylinder. The cylinder was immersed in a water bath consisting of 10.00 kg of water at an original temperature of 25.00 °C. When the compound decomposes, the temperature of the water rises to 29.52 °...
*Saturday, October 23, 2010 at 11:32am by Nora*

**Urgent Chemistry Problem!!**

Calculate Delta G at 298 K for the following reactions. Ca(s) + CO2(g) + 1/2O2(g) -> CaCO3(s) 2KClO3(g) -> 2KCl(s) + 3O2(g) CH4(g) + 3Cl2(g) -> CHCl3(g) + 3HCl(g) Delta G^0f CHCl3 is - 70.4 kJ/mol The following reactions are important ones in catalytic converters in ...
*Monday, April 1, 2013 at 5:20pm by Amy*

**chemistry**

delta G = delta H -TdeltaS. Generally, but not always, if delta H is negative, then delta G is more likely to be negative, and the reaction will be spontaneous. But delta H can be + and the temperature can be high enough to make the TdeltaS term override the + delta H and ...
*Tuesday, April 22, 2008 at 10:17pm by DrBob222*

**Chemistry**

Answered previously. The delta Hs you have listed. Is that per mol or per gram? And the unit is J or kJ? Write balanced equations for the combustion of each gas. 0.800 x 1.00 x delta H CH4 = ?? 0.200 x 1.00 x delta H C2H6 = xx ?? + xx = total for mixture. Note: If delta H is J...
*Thursday, November 1, 2007 at 9:18pm by DrBob222*

**chemistry**

2. Methanol, CH3OH, is used as fuel in race cars. This liquid fuel can be synthesized using the following process C(s)+ ½ O2(g) + 2H2(g) CH3OH(l) Calculate delta G using the deta Gf of the reaction. Calculate Kp. What is the relation between the magnitude of delta G ...
*Thursday, April 15, 2010 at 7:32am by Kristen*

**Chemistry Urgent**

Do you want enthalpy/grams or enthalpy/mol. Most prefer it to be kJ/mol. q = g H2O x specific heat H2O x (Tfinal-Tinitial) That gives you q/2.30g X = ? J/g If you want J/mol it is J/g x 82.0 = ? J/mol. You can change that to kJ/mol if you wish.
*Tuesday, March 11, 2014 at 10:35pm by DrBob222*

**Physics**

The bulk modulus of water is 2.2*10^9 Pa. You omitted some terms. Use the formula which you wrote But with a minus sign) to solve for (delta V/V). At 33 m depth, the delta P is 33*10^4 Pa You will find that deltaV/V is a small fraction at this depth. Then find that delta P ...
*Wednesday, November 14, 2007 at 10:43pm by drwls*

**Chemistry**

Given the thermodynamic data in the table below, calculate the equilibrium constant for the reaction: 2SO2(g)+O2--> 2SO3 Substance (DeltaH^o) (Delat S^o) SO2 -297 249 O2 0 205 SO3 -395 256 Answer (it was given) 2.32x10^24 Even though the answer is given (2.32x10^24) I just ...
*Sunday, March 16, 2008 at 12:00am by Sara*

**Chemistry**

Given the thermodynamic data in the table below, calculate the equilibrium constant for the reaction: 2SO2(g)+O2--> 2SO3 Substance (DeltaH^o) (Delat S^o) SO2 -297 249 O2 0 205 SO3 -395 256 Answer (it was given) 2.32x10^24 Even though the answer is given (2.32x10^24) I just ...
*Sunday, March 16, 2008 at 10:23pm by Sara*

**calculus**

f(x+delta x)-f(x)/delta x = [2(x+delta x)^2 -4 -2x^2 +4]/(delta x) = [2x^2 + 4(x delta x +(delta x)^2 -2x^2 +4]/(delta x) = 4x + delta x Which becomes 4x when delta x -> 0
*Thursday, October 1, 2009 at 7:12pm by drwls*

**Chemistry**

How would you calculate delta H for the following reaction: 2P + 5Cl2 -> 2PCl5 Given: PCl3 + Cl2 -> PCl5 Delta H=-87.9 kJ 2P + 3Cl2 -> 2PCl3 Delta H=-574 kJ I have no clue how to do this since I was absent. Can someone help?
*Tuesday, March 3, 2009 at 1:05pm by Samantha*

**Chemistry**

MnO2(s) -> MnO(s) + 1/2O2(g) Delta H1 = +32.5 kcal MnO2(s) + Mn(s) -> 2MnO(s) Delta H2 = -59.0 kcal Calculate Delta H final of MnO2 in KJ. The answer is not as important to me as the explanation. So, can someone please show me how to do this type of a problem?
*Monday, April 26, 2010 at 2:57am by Lisa*

**chemistry**

what is the difference between these two equation: delta G= delta H-T(delta S) and deltaG(knot)=delta H(knot)-T(delta S knot) Which G do i use to tell whether the reaction is spontaneous
*Sunday, October 17, 2010 at 3:05am by nighter*

**chemistry**

what is the difference between these two equation: delta G= delta H-T(delta S) and deltaG(knot)=delta H(knot)-T(delta S knot) Which G do i use to tell whether the reaction is spontaneous
*Sunday, October 17, 2010 at 5:50pm by nighter*

**Physics**

the velocity when the ball first contacts the floor is: V1 = sqrt(2*g*s) V1= sqrt(2 * 9.8(m/s^s) * 1.8m) The velocity when the ball just leaves (rebounds) works the same way except for the distance sign V2 = sqrt(2 * 9.8(m/s^2) * (-1.06m)) V1 - V2= delta V (you will be ...
*Thursday, October 4, 2007 at 6:47pm by Quidditch*

**chemistry**

delta H rxn = delta H products - delta H reactants. Look up delta H formation in your text or on line.
*Sunday, October 19, 2008 at 10:26pm by DrBob222*

**Chemistry**

delta E = delta m x c^2 2.5165E11 J = delta m x (3E8)^2 and delta m should come out in kg; BUT I don't see a choice there.
*Wednesday, May 16, 2012 at 2:21pm by DrBob222*

**chemsitry**

Basically, this is as follows: delta Hrxn = (delta H products) - (delta H reactants) Where delta H products and delta H reactants follow this set up. #moles*delta H product 1 + # moles*delta H product 2.....
*Saturday, October 23, 2010 at 2:36pm by DrBob222*

**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 ...
*Thursday, August 2, 2007 at 8:39am by Vic*

**chemistry**

Q = m*c* [(delta)T] where Q= heat, m=mass, c=specific heat capacity, and delta T= change in temperature
*Friday, October 1, 2010 at 1:44pm by TutorCat*

**chemistry**

these are my three thermochemical equations 2Cu(s)+S(s) give Cu_2S(s) delta H -79.5 KJ S(s)+O_2 give SO_2(g) -297 KJ Cu_2S(s)+2O_2(g) give 2CuO(s)+SO_2(g) how i calculate standard enthalpy of formation in Kj per mol of CuO(s)? please dont give the answer only guid me please
*Sunday, April 11, 2010 at 3:57pm by mohd*

**chemistry**

delta H rxn = (delta H products-delta H reactants). You will need to look up the delta H for H2O unless you have it and didn't post it.
*Sunday, September 20, 2009 at 9:21pm by DrBob222*

**Chemistry**

A .25 g chunk of sodium metal is cautiously dropped into a mixture of 50g of water and 50 g of ice both at 0 C 2Na(s) + 2h2o(l) -> 2naoh(aq) + H2 Delta H = -368 kj Will the ice melt Assuming the final mixture has a heat capacity of 4.18 J/g C calculate the final ...
*Sunday, January 15, 2012 at 3:29pm by Adriths*

**Chemistry**

A .25 g chunk of sodium metal is cautiously dropped into a mixture of 50g of water and 50 g of ice both at 0 C 2Na(s) + 2h2o(l) -> 2naoh(aq) + H2 Delta H = -368 kj Will the ice melt Assuming the final mixture has a heat capacity of 4.18 J/g C calculate the final ...
*Monday, January 16, 2012 at 2:33pm by Adriths*

**Physic please help!**

The change in B divided by the time (0.45 s), multiplied by the loop area in square meters, is the average voltage in the loop during the interval. The wire resistance is 2 pi R * 3.3 10-2 ohms(?)/m. Coumpute the average current (Vav/R) and multiply it by the average voltage, ...
*Tuesday, October 9, 2007 at 6:32pm by drwls*

**Chemistry**

Look up delta Go for each, then delta Gorxn = (delta Goproducts)-(delta Goreactants)
*Thursday, June 3, 2010 at 4:52am by DrBob222*

**Chemistry**

q = 16,770 x delta T =? J delta H/g = ?J/2.839 delta H/mol = delta H/g x molar mass
*Monday, September 17, 2012 at 9:08pm by DrBob222*

**Chemistry**

Clapeyron equation: dp/dT = ΔS / ΔV My textbook says, for fusion/melting reactions: dp/dT = ΔH / (T ΔV) this implies that T * ΔS = ΔH. I know T * ΔS = q and at constant pressure, that equals H, but the dp/dT reaction is not at constant...
*Wednesday, March 11, 2009 at 12:59pm by reed*

**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 ...
*Thursday, November 18, 2010 at 1:32am by Ricardo*

**Chem**

Calculate delta H for the formation of one mole of N2O5 from the elements at 25 degrees C using the following data. 2H2 + O2 - 2H2O delta H = -571.6 kJ N2O5 + H2O - 2HNO3 deltaH = -73.7 kJ 1/2N2 + 3/2O2 + 1/2H2 - HNO3 delta H = -174.1 kJ
*Thursday, April 8, 2010 at 3:26pm by Anonymous*

**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.
*Monday, November 22, 2010 at 3:24pm by Tara*

**chemistry**

For a certain reaction, Delta H(not) = -76.8 kj and delta S(not) = -217 j/k. If n =3, calculate E for the reaction at 25degrees celcius.
*Wednesday, November 24, 2010 at 1:08am by Tara*

**chemistry**

delta T = Kf*i*m You know Kf, i, and m. Calculate delta T and subtract from the normal freezing point of water which is zero degrees C.
*Wednesday, January 27, 2010 at 2:13am by DrBob222*

**physics help please**

(b) Since the pressure is constant, T is proportional to V in this process. Use the ideal gas law to get the initial temperature. (c) Heat added = Internal energy change + work done = (3/2)R(delta T)*n + P *delta V
*Sunday, December 14, 2008 at 10:56pm by drwls*

**Chemistry**

Multiply eqn 1 by 2 and reverse. Multiply the delta H value by 2 and change the sign. Multiply eqn 2 by 2 and reverse it. Multiply the delta H value by 2 and change the sign. Add the new eqn 1 + eqn 2 along with eqn 3 and you get twice the equn you want. Add new delta H values...
*Wednesday, November 14, 2012 at 4:24pm by DrBob222*

**Chemistry**

1. Use standard entropies and heats of formation to calculate delta-G of formation at 25° C for a) cadmium(II) chloride (s) b) methyl alcohol, CH3OH (l) c) copper(I) sulfide (s) My problem is that I don't know how to calculate delta-G of formation. I know that the Gibbs-...
*Sunday, March 4, 2007 at 4:03pm by Chris*

**chemistry (for DrBob222)**

Yes, NaOH is added to the water. How much will adding twice the mass of NaOH will change Q? I am asked what would have been the heat evolved based on my actual observations and what effect would this have on my calculation of (delta)H. Would saying "based on the assumption ...
*Friday, July 18, 2008 at 6:02pm by Anonymous*

**college: Chemistry**

delta E = hf Substitute 4.34 x 10^-19 for delta E, substitute Planck's constant for h and calculate frequency.
*Sunday, February 15, 2009 at 2:06am by DrBob222*

**chemistry**

Data: SO2(g) + ¨öO2(g) ¡æ SO3 (g) ¥ÄH = -99.1 kJ Given the above data, calculate the enthalpy change ¥ÄH when 89.6 g of SO2 is converted to SO3.
*Sunday, October 16, 2011 at 7:52am by syd*

**Calculus - Riemann Sum**

Given a function f(x) = squr(3 + 2x), on [-1,1], subdivided into 4 equally large intervals, calculate the Riemann sum SR4 = 4Ei=1 f(xi)delta(x). my attempt at the solution: [-1,1], a = -1 and b = 1 delta(x) = 1 - (-1)/n = 2/n xi = a + delta(x)i xi = -1 + 2/n(i) so after adding...
*Monday, August 6, 2012 at 10:07pm by Robert*

**Chemistry**

Calculate (from tables) delta Go for each reaction, then delta Go = -RT*lnK.
*Sunday, July 18, 2010 at 10:04pm by DrBob222*

**ap chemistry**

Since delta G = delta H - T*delta S, for constant delta S, increasing T will make the right term more negative and that will make delta G more negative. I don't know what you mean by "increasing" delta G, especially when dealing with negative numbers. The safe way to answer ...
*Wednesday, February 27, 2008 at 7:36pm by DrBob222*

**Chemistry**

Calculate the molar enthalpy for the following reaction. HCl(aq) + NH3 (aq) --> NH4Cl (aq). HCl = 50 ml (2.00M) NH3 = 50 ml (2.05 M) Delta T = 9.28 degrees Celsius. Ccal = 28.9J/g degrees celcius.
*Monday, November 12, 2012 at 11:05pm by Emma*

**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 ...
*Sunday, November 17, 2013 at 8:08pm by Matt*

**Chemistry**

Do you know how to calculate the heat of the reaction; i.e., delta Hrxn? Write the equations. CH4 + 2O2 ==> CO2 + 2H2O CH3OH + 2O2 ==> CO2 + 2H2O Now look up in your text the delta Hof for each of the products and reactants (elements are zero) delta Hrxn = delta ...
*Saturday, February 16, 2008 at 1:41pm by DrBob222*

**Chemistry**

deltaHrxn = (n*deltaHf products) - (n*deltaHf reactants). Look up delta Hf values, substitute, and calculate delta H rxn.
*Sunday, April 24, 2011 at 11:14pm by DrBob222*

**Chem**

Hydrogen peroxide decomposes according to the following: H2O2--> H2O(l) + 1/2O2(g); deltaH = -98.2kJ Calculate the change in enthalpy, deltaH, when 1.00g of Hydrogen peroxide decomposes
*Thursday, November 19, 2009 at 4:29pm by Lindsey*

**Physical Chemistry**

I'm not positive I understand exactly; however, the delta G you are looking up is for 25 C. It is not for 100 C. I suspect that is your problem. Can you correct for that by using delta G = delta H - T*delta S.
*Friday, February 19, 2010 at 9:29pm by DrBob222*

**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)
*Friday, November 5, 2010 at 10:08pm 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)
*Friday, November 5, 2010 at 10:21pm by Anonymous*

**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?
*Wednesday, October 8, 2008 at 4:29pm by tomi*

**Chemistry**

Are my answers correct? C6H14 + 19/2 O2 -> 6 CO2 + 7H2O enthalpy change = -4163 kJ a) if 0.537 mol of carbon dioxide is produced in the reaction represented by the equation above, how much heat is released by the reaction? Enthalpy change = 0.537 mol CO2 x -4163kJ/6 mol CO2...
*Sunday, February 10, 2013 at 11:33pm by A Canadian*

**Chemistry**

If the cyclohexane is initially contaminated with a soluble non-reactive, non-volatile substance, will the change in freezing point, delta Tf, be a. Higher b. Lower c. The same as the uncontaminated cyclohexane? There will be no change hence delta Tf will be the same as the ...
*Tuesday, March 22, 2011 at 2:30am by Cassie*

**Chemistry**

Calculate the enthalpy change when 100. g of ice at 0.0 °C is heated to liquid water at 50.0°C. (The heat of fusion for water is 333 J/g.) 1)54.2 kJ 2)33.3 kJ 3)54,220 kJ 4)20.9 kJ
*Tuesday, October 23, 2007 at 9:39pm by Robert*

**Chemistry(Please check)**

Delta G^o for a reaction can be calculated from? 1. delta G^o f data 2. Delta H^o f and delta S data 3. equilibrium constants I chose that delta G can be calculated from H and S values. Would you agree?
*Sunday, April 22, 2012 at 11:46pm by Hannah*

**Chemistry**

Can you turn the reaction around (which will change the sign of K?) and work it that way. Then after finding delta G for the reverse direction, that can be reversed again for delta G in the original direction.
*Sunday, February 17, 2008 at 5:24pm by DrBob222*

**Chemistry**

Can you turn the reaction around (which will change the sign of K?) and work it that way. Then after finding delta G for the reverse direction, that can be reversed again for delta G in the original direction.
*Sunday, February 17, 2008 at 5:24pm by DrBob222*

**Chemistry**

Can you turn the reaction around (which will change the sign of K?) and work it that way. Then after finding delta G for the reverse direction, that can be reversed again for delta G in the original direction.
*Sunday, February 17, 2008 at 5:24pm by DrBob222*

**Chemistry**

1: Set all the delta g's for solids equal to 0 2:Find thr delta g for the gases. 3:Find the delta g for the second equation. 4:Add the delta g's for the 2 questions together. 5: Solve for the value of Q using the equation -Delta G not =RTLnQ
*Wednesday, March 14, 2012 at 11:51pm by Janavi*

**CHEMISTRY- PLEASE HELP:)!**

delta T = Kf*m You know delta T (43-39) and you know m. Calculate Kf.
*Wednesday, April 16, 2008 at 9:46pm by DrBob222*

**Chemistry (How do I calculate) **

Calculate the Molar Enthalpy of Neutralization (ΔHn) in kJ/mol of the reaction between a monoprotic acid and a monoprotic base, given the following information: The temperature change equals 6.92°C, 50.0 mL of 1.00 M concentration of Acid 50.0 mL of 1.00 M concentration ...
*Friday, June 28, 2013 at 3:43pm by Ashley*

**Physics**

The more correct way to write the change of momentum equation is F = (delta p)/(delta t) If there is a time-varying force, the above equation applies for short time intervals, in the limit as delta t approaches zero. Using calculus notation, one writes f = dp/dt If there is NO...
*Saturday, October 3, 2009 at 12:25pm by drwls*

**Chemistry**

Given the following data, calculate the enthalpy change for the reaction S(s)+ O2(g)->SO2(g) S(s)+(3/2)O2(g)->SO3(g) H=-395.2 kJ 2SO2(g)+ O2(g)->2SO3(g) H=-198.2 kJ
*Tuesday, January 10, 2012 at 11:10pm by Alisa*

**chemistry**

a. heat combustion = [delta H products]-[delta H reactants]. 1. You know what 1 mole is, set up ratio/proportion for 00108 mol. This is q. 2. q = 9.273 kJ/c x delta T. Solve for delta T.
*Wednesday, March 10, 2010 at 7:28pm by DrBob222*

**chemistry**

delta Go = -RTlnK Look up values of delta Go for O3 and O2, delta Go rxn = delta Goproducts - delta Go reactants.
*Sunday, November 23, 2008 at 1:01am by DrBob222*

**Finding Delta G**

The following reactions are important ones in catalytic converters in automobiles. Calculate Delta G for each at 298 K. Predict the effect of increasing temperature on the magnitude of Delta G. 2CO(g) + 2NO(g) -> N2(g) + 2CO2(g) 5H2(g) + 2NO(g) -> 2NH3(g) + 2H2O(g) 2H2(g...
*Friday, March 29, 2013 at 1:06pm by Amy*

**chemistry**

Calculate the Delta G(not) for the reaction: C(s) + CO2 (g) --> 2 CO Delta Gf : CO2 = -394.4 kj/mol Delta Gf : CO = -137.2 kj/mol
*Monday, November 22, 2010 at 3:19pm by Tara*

**Physics**

change in volume = surface area * delta h delta volume/volume = 45 * 9.5 * 10^-4 volume = 3 liters = 3*10^-3 m*3 so delta volume = 3 *10^-7 *45 * 9.5 = 1282*10^-7 m^3 surface area = .135*.13 = 1.755*10^-2 so 1.282*10^-4 = 1.755 *10^-2 delta h delta h = .73 * 10^-2 meters or ....
*Friday, January 17, 2014 at 5:35pm by Damon*

**Physics HELP!!!!!!!!**

Suppose a monatomic ideal gas is contained within a vertical cylinder that is fitted with a movable piston. The piston is frictionless and has a negligible mass. The area of the piston is 3.06 10-2 m2, and the pressure outside the cylinder is 1.02 105 Pa. Heat (2109 J) is ...
*Saturday, April 21, 2007 at 1:23am by Mary*

**Chemistry**

One cubic meter of ideal diatomic gas is expanded from 150oC, 8 bar isothermally to the final volume. The gas is then cooled at constant volume until 50oC and 3 bar. Calculate the total change in work, heat, enthalpy, and internal energy.
*Tuesday, April 9, 2013 at 10:36pm by BASSS*

**PHYSICS**

The change in internal energy is delta U = (3/2)R*(delta T)*n where n is the number of moles. delta T is only 1.1 K in this case. Note: (3/2)R is the specific heat at constant volume of any monatomic gas Get the number of moles from n = PV/RT Use the initial P and T. V = 680 m...
*Thursday, February 21, 2008 at 10:31pm by drwls*

**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...
*Tuesday, February 25, 2014 at 9:14pm by Smith*

**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?
*Sunday, February 20, 2011 at 8:18pm by Anonymous*

**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. (ΔH°f for H2, ...
*Monday, October 27, 2008 at 11:24pm by hannah*

**chemistry**

I'm not sure I will get all of the questions but I'll start. First, O2 is zero (by definition, I suppose) since anything in the standard state is zero. That's how delta H is defined. Look in your table and you will find O2, H2, Cl2, etc (in the free state) is zero in the ...
*Monday, April 19, 2010 at 4:19pm by DrBob222*

**Chemistry**

For a particular reaction at 195.1 °C, ΔG = -1488.09 kJ/mol, and ΔS = 288.67 J/(mol·K).? Calculate ΔG for this reaction at -20.0 °C. delta G = delta H - (T*delta S) -1488.09 kJ/mol = (delta H) - ((461.8K)*(+288.67 J/(mol x K))*(1 kJ/1000 J)) -1488.09 kJ/mol = (...
*Tuesday, April 30, 2013 at 4:01pm by Dee*

**Chem Urgent Help**

Plz explain in detail.... i tried to search on internet but i am confused with co-efficents.. how to set up the equaiton .. plz help me ??? Bond enthalpy is the energy required to break a mole of a certain type of bond. O=O = 495 kj/mol S-F = 327 kj/mol S=O = 523 kj/mol Use ...
*Wednesday, November 12, 2008 at 10:18pm by Sarah*

**Chemistry**

Hydrogen peroxide, H2O2, is a colorless liquid whose solutions are used as a bleach and an antiseptic. H2O2 can be prepared in a process whose overall change is the following. H2(g) + O2(g) H2O2(l) Calculate the enthalpy change using the following data. H2O2(l) H2O(l) + 1/2 O2...
*Saturday, October 18, 2008 at 10:36pm by Glenna*

**Chemistry**

One of my homework problems deals with finding the change in entropy of the surroundings using the equation delta(S)= -delta(H)/T(temp.) The numbers given were T=263K and delta(H)fusion=6.0*10^(3) J/mol I know how to solve the problem, I just want to know why it is that even ...
*Sunday, February 24, 2013 at 12:39am by Confused*

**College Chemistry**

Make sure the equation is balanced. Is this for "so-called" standard conditions? If so, go the tables in your text and look up delta Hfo values. delta H rxn = (delta H products) - (delta H reactants). That will give you the delta H for the reaction for 64 g oxygen. Set up a ...
*Tuesday, March 30, 2010 at 2:38pm by DrBob222*

**Thermodynamics**

Both dQ and dW are zero. Therefore dU = 0 That means the temperature does not change. Pressure decreaseds by a factor of two because of the doubled volume of the gas. Enthalpy also doesn't change because PV = constant along with U.
*Monday, March 15, 2010 at 7:47pm by DrWLS*

**Organic Chemistry**

Not quite sure I understand the question. If we go to the Gibb's free energy equation: delta G = delta H - (T)(delta S) where T is the temperature in kelvin Remember that a more negative value of delta g is more spontaneous, and a large positive value of delta g is less ...
*Tuesday, December 1, 2009 at 11:07pm by Dr Russ*

**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)
*Friday, November 5, 2010 at 9:57pm by Anonymous*

**Physics**

Determine the velocity just as the ball makes first contact with the floor. Determine the velocity as the ball just just leaves the floor. Calculate the delta velocity. Divide this by the delta t to get (delta v)/((delta t) which is average acceleration. Look for the forumula ...
*Thursday, October 4, 2007 at 3:47pm by Quidditch*

**Chemistry**

Please help, I am having trouble solving these problems at nonstandard temperatures. Methanol burns in oxygen to form carbon dioxide and water. Using the balanced reaction, 2CH3OH(l) + 3OH2(g) --> 2CO2(g) + 4H2O(g) 1) Calculate delta H(rxn) in kJ at 24 degrees Celsius 2) ...
*Sunday, July 18, 2010 at 7:30pm by Miguel*

**AP Chemistry**

2SO2 + O2 ==> 2SO3 Initial values: SO2 = 8.00 mols and (SO2) = 8.00/2 = 4.00M O2 = 10.00 mols and (O2) = 10.00/2 = 5.00 M At equilibrium: (SO3) = 2x (O2) = 5.00-x (SO2) = 4.00-2x Plug into the equilibrium constant expression and solve for x. Then you can calculate the other...
*Saturday, January 12, 2008 at 10:45pm by DrBob222*

**chemistry**

Using data in table below and S °(C2H6(g))= 229.5 J·mol-1·K-1, calculate ÄfS° for C2H6(g) in J·mol-1·K-1. Compound S °, J·mol-1·K-1 Compound S °, J·mol-1·K-1 C(s) 5.69 H2(g) 130.6 I am sorry , last time i did not show my working. thanks for helping me . Delta S= Delta S ...
*Saturday, May 15, 2010 at 9:35pm by write2khin*

**Chemistry**

The long way is to make up a value for q and m and calculate delta T for each metal as in q = m*c*delta T then choose the one that has the highest delta T value. The more esoteric way is to reason it out. q = mcdelta T and solve for delta T. dT = q/m*c The problem says q is ...
*Saturday, April 28, 2012 at 11:07am by DrBob222*

**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 ...
*Thursday, April 18, 2013 at 11:02am by Yasemine*

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