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April 20, 2014

Search: chemistry - hess's law (check + help)

Number of results: 144,279

chem expirement!
You are required to design an experiment to test Hess's law using the combustion of ethanol. Write a brief design for this experiment. What I wrote as my answer: Hess Law: is the algebraic addition of chemical equations yields a net equation whose enthalpy of reaction is the ...
Thursday, May 17, 2007 at 12:28pm by rob

chem experiment:
You are required to design an experiment to test Hess's law using the combustion of ethanol. Write a brief design for this experiment. What I wrote as my answer: Hess Law: is the algebraic addition of chemical equations yields a net equation whose enthalpy of reaction is the ...
Thursday, May 17, 2007 at 11:23am by rob

Chemistry Hess's Law
(1) 2 Ni(s) + O2 (g) --> 2NiO(s) delta H= -479.4 kJ (2) Ni(s) + Cl2(g) --> NiCl2(s) delta H= -305.3 kJ Using equations 1 and 2 and Hess's Law, determine the amount of moles Nickel (ii) Chloride that was combusted given the following: volume = 15.45 L pressure = 2.29 atm...
Wednesday, October 23, 2013 at 9:20pm by Brian

Chemistry
Use Hess' Law.
Sunday, February 24, 2008 at 3:40pm by DrBob222

College Chemistry- Hess's Law
-109.5
Friday, October 22, 2010 at 8:43pm by Bri

chemistry
By calculating it using Hess' Law.
Monday, November 25, 2013 at 11:03pm by DrBob222

chemistry - hess's law (check + help)
It appears to me that the first equation x 3 gives 3C(graphite) and the fourth x 4 and reversed gives 4C(graphite) so those don't cancel. I stopped there.
Wednesday, June 8, 2011 at 2:37pm by DrBob222

chemistry
At 25 C the following heats of reaction are known: 2CIf (g)+ O2(g) -> CL2O (g) + f2O Delta H rxn= 167.4 kj/mol 2CIf3(g) + 2O2 (g)-> Cl2O(g) + 3F2O(g) Delta H rxn= 341.4 2F2(g) + O2(g) -> 2F2O(g) Delta H rxn= -43.4kj/mol at the temperature, use Hess's Law to calculate ...
Sunday, March 4, 2012 at 10:10pm by Court

Chemistry
Did you look up on the internet what Hess'Law is? That might help?
Wednesday, February 20, 2008 at 1:49pm by Mathilde

Chemistry
Look up Hess' Law. See if it agrees with Statement D.
Wednesday, February 20, 2008 at 1:49pm by DrBob222

Chemistry
i dont understand how and why you use Hess's law to find the equilbiruim constant
Sunday, October 31, 2010 at 1:42pm by MEG

Chemistry
Explain why the calculated value for the (1) enthalpy of combustion for propane using bond energies (bond breaking and bond formation)might not be in close agreement to the values calculated using (2) Hess Law and the values calculated using the (3) summation of the change in ...
Monday, November 1, 2010 at 11:40am by Leah

Chemistry(Please check)
I agree. By the way, I looked at the 2CH4 equation posted by another student and I did not obtain 338 kJ for that Hess' Law problem. You may want to revisit that problem. I specifically remember that I agreed with your answer of 338 kJ. Now I think I was incorrect.
Saturday, January 28, 2012 at 11:55pm by DrBob222

chemistry
if enthalpies for formation of p4o10, h2o and h3po4 are -2984, -285.9 and -1279 respectively calculate the enthalpy change using hess's law
Wednesday, July 4, 2012 at 7:25am by mala

College Chemistry- Hess's Law
Multiply equation 2 by 2 and reverse it. Add in equation 1. That will give you what you want.
Friday, October 22, 2010 at 8:43pm by DrBob222

chemistry
Using Hess' Law.... 3*(-390)+4(-240)-Hf=-2440 solve for Hf(propane).
Thursday, January 13, 2011 at 9:06pm by bobpursley

Hess' law
asdfasd
Friday, February 9, 2007 at 12:34am by Anonymous

Chemistry
Hess Law: sum heats products-sum reactants 8*-228.6 + 6*-394.4-2*360.5= which does not match your answer.
Friday, June 21, 2013 at 1:44pm by bobpursley

Chemistry
I flipped the second equation around to go with Hess's law which gives me a h value of 359.4 for the second one but I am lost after that.
Tuesday, April 7, 2009 at 10:27pm by Kathryn

chemistry - hess's law (check + help)
31. Carbon monoxide reacts with hydrogen gas to produce a mixture of methane, carbon dioxide, and water. (This mixture is known as substitute natural gas.) 4CO(g) + 8H2(g) → 3CH4(g) + CO2(g) + 2H2O(_) Use the following thermochemical equations to determine the enthalpy ...
Wednesday, June 8, 2011 at 2:37pm by Farah

Hess' law
Which of the following is the best definition of Hess' Law? A. Heat is always released by the decomposition of 1 mole of a compound into its constitute elements. B. Since enthalpy is a state function, it will be different if a reaction takes place in one step or a series of ...
Friday, February 9, 2007 at 12:34am by christine

chemistry
Hess Law: Hf(CaCl2) + 2*Hf(H2O)-Hf(Ca(OH2))-2Hf(HCL)=-53.4kJ
Sunday, March 18, 2012 at 6:24pm by bobpursley

CHEMISTRY
And I need to correct my first response. After reading GK's response, I realize I called this the Born-Haber cycle. That is similar but this is an example of Hess's Law.
Monday, September 22, 2008 at 8:13pm by DrBob222

chemistry
I don't understand how you do (b), I got 173kJ for (a) and I understand Hess's law for (c), but (b) I really don't understand (b)
Wednesday, March 30, 2011 at 8:52pm by Chem

Chemistry
Use Hess' Law to calculate the heat of the following equation. Show all work including the reactions that you use, in the form that you use them. 2 C + 2 NO2 ---> 2 CO 2 + N 2
Sunday, April 24, 2011 at 11:14pm by Kat

Chemistry
Edna. I gave you the answer from Hess' Law. Here is what I suggest: It seems to me that something really simple has you flustered and you are not seeing the process of solution. Find a classmate who can sit down with you and go thru some of these. Quickly before you are ...
Saturday, June 6, 2009 at 5:52pm by bobpursley

chemistry - decomposition of water(help)
Thank you, helped, the equations do balance out, and there are more than one ways to solve this either by multiplying the first equation by 2 and then manipulating further as well as just canceling out and adding all by hess's law.
Thursday, March 3, 2011 at 11:05am by Farah

Chemistry!!
I do, but I wasn't sure if I even was doing the right thing, so I didnt bother. But ok so, the equation would be: 2 Fe + 1/2 O2 > Fe2O3 right...and then what do I do? Heat of formation and do the Hess' law equation of products-reactants? Thanks. L
Saturday, November 22, 2008 at 12:29pm by Lulu

Chem 1LB
You would times it by the momentum currency of memorandum which is stated in Hess's law of physics
Sunday, February 21, 2010 at 4:49pm by DrBob222

Chemistry
Hess's law _____. A.) makes it possible to calculate H for complicated chemical reactions B.) states that when you reverse a chemical equation, the sign of H does not change C.) determines the way a calorimeter works D.) describes the vaporization of solids Please help - I ...
Monday, March 4, 2013 at 2:21pm by Jack

check american government
The constitution and the amendments thereto are passed by the required majorities, and are binding law. The law of this land is that the law is the law, an it is is own justification. Promises are not law.
Sunday, October 26, 2008 at 8:31pm by bobpursley

Chemistry
1. Hess's law _____. A.) makes it possible to calculate H for complicated chemical reactions B.) states that when you reverse a chemical equation, the sign of H does not change C.) determines the way a calorimeter works D.) describes the vaporization of solids Please help me...
Monday, March 4, 2013 at 11:52am by Jack

CHEMISTRY
You know the delta T for the metal and the water. heat=masswater*cw*deltaT +massnickel*cn*deltatT b) use that heat, per mole of acetone consumed (convert grams to moles) c) Use Hess'law.
Sunday, September 30, 2007 at 10:37pm by bobpursley

chem
Is A,B,C,D standard heats of formation? If so, then by Hess' Law.. Hr=2(C)+D-2(A)-B That hear of reaction is when 2 moles of A react, so, multiply it by 1.5.
Wednesday, October 8, 2008 at 4:29pm by bobpursley

Chem
What is an experimental technique that could be used to determine the enthalpy of combustion of magnesium directly? Not using Hess's Law!! any help is appreciated :)
Sunday, November 23, 2008 at 10:33pm by z.

Chemistry - General, Hess's Law
Do you have a calorimeter constant listed? Or some way to calculate the constant? The heat gained by the solution (part a) is mass x specific heat x (Tfinal-Tinitial) 111.6 x 3.63 x (31.8-24.5) = ??
Friday, July 24, 2009 at 6:26pm by DrBob222

Chemistry/hydrolysis of ATP
You will have to compute the heat of reaction for the reaction using Hess'Law. Then, divide it by 20.5kJ. You may find the heat of reaction listed under heat of combustion tables.
Thursday, August 28, 2008 at 11:06am by bobpursley

bus 475
hess inc sells a single product with a contribution martgin of $12 per unit and fixed costs of $74400 and sales for the current year of $100000. how much is hess break even point?
Monday, January 18, 2010 at 2:17pm by Anonymous

Accounting
Hess, Inc. sells a single product with a contribution margin of $12 per unit and fixed costs of $74,400 and sales for the current year of $100,000. How much is Hesss break even point?
Sunday, June 13, 2010 at 1:44pm by Anonymous

stats
Hess, Inc. sells a single product with a contribution margin of $12 per unit and fixed costs of $74,400 and sales for the current year of $100,000. How much is Hesss break even point?
Wednesday, July 7, 2010 at 2:04am by Ali

managerial accounting
Hess,Inc.Sells a single product with a contribution margin of $12 per unit, fixed costs of $74,400, and sales for the current year of $100,00. How much is Hess's Break even point?
Tuesday, July 10, 2007 at 8:31pm by cathalina

Chemistry
1. Hess's law ____. (1 point) (1 pt) makes it possible to calculate H for complicated chemical reactions (0 pts) states that when you reverse a chemical equation, the sign of H does not change. (0 pts) determines the way a calorimeter works (0 pts) describes the vaporization ...
Monday, March 4, 2013 at 11:52am by cupcake

Chemistry
Look in your text about Hess' Law. That is what this problem is. The idea is to multiply (if necessary) an equation AND/OR reverse it so that all of them added together will give you the final equation you want. If you get stuck let us know what you don't understand (be ...
Monday, December 24, 2007 at 5:28pm by DrBob222

Chemistry
The combustion reaction for benzoic acid C6H5CO2H(s) + 15 2 O2(g) → 7 CO2(g) + 3 H2O(ℓ) has ∆H0 = −3226.7 kJ/mole. Use Hesss Law to calculate ∆H0 f for benzoic acid.
Sunday, October 7, 2012 at 7:43pm by Austin

Chemistry
The phrase the heat absorbed or released by a system undergoing a physical or chemical change at constant pressure is a. the change in enthalpy of the system. b. the change in internal energy of the system. c. the definition of a state function. d. the temperature change of ...
Tuesday, July 2, 2013 at 5:09pm by Jessica

Chemistry
Hess' law. Multiply equation i by 2 (multiply H by 2 also) and add to equation ii. That will give you the equation you want so delta H for the final reaction is the sum of 2*i + ii = final rxn.
Wednesday, April 6, 2011 at 11:58am by DrBob222

ap chemisty
Balance this equation butane+O2 >> CO2 + H2O Then, apply Hess' Law. I will be happy to critique your thinking.
Friday, September 24, 2010 at 5:30pm by bobpursley

ap chemisty
Balance this equation butane+O2 >> CO2 + H2O Then, apply Hess' Law. I will be happy to critique your thinking.
Friday, September 24, 2010 at 5:30pm by bobpursley

Chemistry
When solving Hess law problems,do we need to use all the equations given to get the Htotal or just choose the relevant equations that are related to the final equation required? Let's say there r 5 equations given,but the relevant equations are 3 only ,so we can neglect the ...
Friday, March 23, 2012 at 2:22am by Meenaakshi

College Chemistry- Hess's Law
Nitrogen oxides undergo many interesting reactions in the environment and in industry. Given the following information, calculate H for the overall equation: 2 NO2(g) + 1/2 O2(g) = N2O5(s). 2 NO(g) + 3/2 O2(g) = N2O5(s), H = -223.7 kJ NO(g) + 1/2 O2(g) = NO2(g), H = -57.1 kJ
Friday, October 22, 2010 at 8:43pm by Tahnee

Chemistry
Why wouldn't you do this reaction directly in a lab (and would rather use Hess' Law to determine the enthalpy of formation)?: 1/2N2(g) + 2H2(g)+ 1/2Cl2(g) -> NH4Cl(s) I don't think the reactants are that dangerous...? It's still pretty safe to do in a lab, isn't it? Are ...
Monday, February 18, 2013 at 7:48pm by a Canadian

Chemistry
Part B: Use the result from part A, data in this chapter (Chapter 7:Periodic Properties of the Elements), and Hess's law to calculate the enthalpy of the above reaction. Part A is: Na(g)--> Na^(+)+e^(-) Cl(g)+ e^(-)--> Cl^(-)(g)
Saturday, November 3, 2012 at 3:54pm by Ezra

Chemistry
Calculate delta H for the reaction below using Hess's Law: C2H6 ---> C2H2 + 2H2 ------------------------------------------ C2H2 + 5/2O2 --> 2CO2 + H2O (H = -1300 kJ) 2H2 + O2 --> 2H2O (H= -572 kJ) 2C2H6 + 7O2 --> 4CO2 + 6H2O (H= -3120 kJ)
Wednesday, November 14, 2012 at 4:24pm by Gabby

Chemistry
Hess' Law. Multiply equation 2 by 2 and reverse it. Multiply equation 3 by 3 and leave as is. Multiply equation 1 by 2 and leave as is. Add the resulting equations. Add the resulting delta Hs also, (after multipling AND changing the sign of those reversed.
Wednesday, June 30, 2010 at 9:13pm by DrBob222

Chemistry
Find the enthalpy for : 4Fe + 3O2 = 2Fe2O3 I got the following informations: Fe + 3H2O = Fe(OH)3 + 3/2H2 - Enthalpy is 160.9 kj H2 + 1/2O2 = H2O - Enthalpy is -285.8 kj Fe2O3 + 3H2O = 2Fe(OH)3 - Enthalpy is 288.6 I try using Hess Law but cannot solve it. Can anyone help me ...
Monday, May 13, 2013 at 2:37pm by Shadow

Science-Chemistry
1. What is Charless law? State the definition of the law in words. What are the assumptions of Charless law? Write mathematical equations that represent the law. What can you do with Charless law? Using a gas-filled balloon as an example, describe what happens to ...
Friday, May 31, 2013 at 2:11pm by Help needed.... Danielle

chemistry
This is an application of Hess' Law. You want to arrange the three equations given to obtain the desired equation. Reverse eqn 3 and 2 and add i eqn 1. When you reverse an equation, change the sign of delta H. If you follow my directions, see if you get the equation you want ...
Monday, January 23, 2012 at 8:05pm by DrBob222

Chemistry
Look up Hess' Law. Multiply equation 1 by 2 and add it to equation 2. Multiply delta H for equation 1 by 2 and add to delta H for equation 2.
Tuesday, March 3, 2009 at 1:05pm by DrBob222

chemistry help please
Given the following data: MnO(s) + H2(g) Mn(s) + H2O(l), H = 100 kJ MnO2(s) + 2 H2(g) Mn(s) + 2 H2O(l), H = 52 kJ use Hess's law to calculate the heat of the reaction MnO2(s) + H2(g) MnO(s) + H2O(l)
Wednesday, January 11, 2012 at 5:46pm by Ari

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 = -...
Friday, March 16, 2012 at 5:10pm by Hailee

Chemistry
That is Hess' Law. IT states that the heat of reaction is equal to the sum of the heats of formations of the products minus the heats of formation of reactions. Example 2HNO3 + Fe >> Fe(NO3)2 + H2 (g) The heat of reaction is equal to the heat of fromation of IronII ...
Sunday, December 14, 2008 at 5:21pm by bobpursley

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.
Wednesday, March 28, 2012 at 5:03pm by Hunter

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= ...
Thursday, December 6, 2012 at 8:58pm by marcus

Chemistry
For a), use Hess' Law. AgCl(s) ==> Ag^+ + Cl^- Ag2CrO4(s) ==> 2Ag^+ + CrO4^-2 b)Since these are equal amounts of NaCl and AgNO3, this will be a saturated solution of AgCl(s) and the solubility is governed by the Ksp for AgCl. AgCl ==> Ag^+ + Cl^- Ksp = (Ag^+)(Cl^-) ...
Sunday, October 31, 2010 at 1:42pm by DrBob222

Hess's law
I need some help with this one please... A+B ----> 2 D H= -765.3 kj S= 344 j/k C ------> D H= 521 kj S= -171 j/k calculate G at 298 K for A+B ------> 2C I know I need to use the formula G= H-TS but I dont know how to get the numbers.
Wednesday, March 20, 2013 at 3:36pm by Caitlin

Math: law of exponents check answers
Look, the law of exponents applies to all... You had a 3^1 in the denominator, specifically (3^1...)^-2 and that changes to 9 in the numerator. Law of exponents does not apply to just variables.
Sunday, September 8, 2013 at 7:53pm by bobpursley

chemistry
Use Hess' Law. Use equation 1 as is. Add to the reverse of equation 2 (change the sign of delta H here) and add to the reverse of equation 3 (change the sign of delta H for 3 also). You should get H + I ==> HI, then add all of the delta Hs together to arrive at a delta H ...
Tuesday, November 16, 2010 at 3:25am by DrBob222

Chemistry
Reposted: Use Hess's law to calculate the enthalpy change for the reaction: 3C(s) + 3H2(g) yield C3H6(g) Given the following thermochemical equations: 2C3H6(g) + 9O2(g) yield 6CO2(g) + 6H2O(l) enthalpy change= -4116.0 kJ/mol C(s) + O2(g) yield CO2(g) enthalpy change= -393.51 ...
Saturday, March 17, 2012 at 11:11am by Hailee

CHEMISTRY
Addendum: This is an example of a Hess's Law problem. Your textbook should have some solved examples. Here is one solved example online: http://answers.yahoo.com/question/index?qid=20080514171625AAsqOoC
Monday, September 22, 2008 at 8:13pm by GK

Chemistry (Hess's Law)
NO2(g) → 1⁄2N2(g) + O2(g) ΔH1 = -33.9 kJ NO2(g) → NO(g) + 1⁄2O2(g) ΔH2 = 56.5 kJ What is ΔH for the reaction 1⁄2N2(g) + 1⁄2O2(g) → NO(g) ?
Friday, April 15, 2011 at 1:52am by Monty

Chemistry
In accordance with Hessfs Law, manipulate the following equations and their Hrxnfs to calculate Hrxn for the reaction HClO4 + NH3 NH4ClO4... HClO4(aq)+ LiOH(aq) LiClO4(aq)+H2O(l) CH3COOH(aq)+ NH3(aq) NH4CH3COO(aq) CH3COOH(aq)+LiOH(aq) LiCH3COO(aq)+H2O(l)
Sunday, July 7, 2013 at 3:21pm by Angela

Chemistry(Please help, thank you)
You have an error on the product side of the third reaction. The reaction produces SnCl4. I was wondering what was wrong Haha. Anyway... Hess's Law...Oh Joy! If we look at the given reactions we see that we must flip three of the reactions to produce the overall reaction that ...
Saturday, February 4, 2012 at 8:51pm by Declan

Chemistry
I will number the equations. 1) AgCl --> Ag^+ + Cl^- Ksp = ?? 2)Ag2CrO4 ==> 2Ag^+ + CrO4^-2 Ksp = ?? Technically, I may not have named it right. Perhaps I should have said in a Hess' Law process. Multilply equation 1 by 2 (which will make Ksp for AgCl squared. Reverse ...
Sunday, October 31, 2010 at 1:42pm by DrBob222

Chemistry check Please
If you wished to use the ideal gas law, yes.
Monday, March 9, 2009 at 8:11pm by DrBob222

chemistry
Use Hess's law and the following equations to calculate H for the reaction N2(g) + 2O2(g) N2O4(g). 2NO2(g)->N2O4(g) H = 57.0 kJ/mol N2(g)+O2(g)->2NO(g) H = 180.6 kJ/mol 2NO2(g)->2NO(g)+O2(gH = 114.4 kJ/mol
Monday, May 14, 2012 at 2:15pm by princess cunningham

CHEM
Can you please check my work? I got -4.3KJ/mol If this is not right can you tell me what I am doing wrong? Thank you! Questions. 1.a. Use Hess's Law and the measured mean enthalpy changes for the NaOH-HCl and NH3-HCl reactions to calculate the enthalpy change to be expected ...
Friday, November 8, 2013 at 3:45pm by Lauren

Chemistry (DrBob222)
OK. I am stunned. After reading your intro to your intro (the comments, instructions of your teacher and comrades in arms) I am inclined to think two pages is too little Your teacher doesn't want an introduction; she wants a book. It would take me two pages or more to describe...
Tuesday, February 19, 2013 at 5:39pm by DrBob222

Chemistry
Which of the following is the best definition of Hess' Law? A. Heat is always released by the decomposition of 1 mole of a compound into its constitute elements. B. The enthalpy of a process is the difference between the enthalpy of the products and the enthalpy of the ...
Wednesday, February 20, 2008 at 1:49pm by Anonymous

HIPPA
please check my answer thanks If HIPPA law is stricter than state law, which standards should you follow and why ? What if state all was stricter ? This is all I have so far any input would be great HIPPA laws are stricter than any state law. This standard over rules any state...
Monday, May 12, 2008 at 11:17am by Casie

chemistry
No, the are not the same. The Combined Gas Law is: P1V1/T1 = P2V2/T2 The Ideal Gas Law is: PV = nRT Your chemistry textbook should explain the difference. The most importance difference is that in the Combined Gas Law, the amount (moles) of gas are assumed to be constant. In ...
Monday, March 2, 2009 at 7:25pm by GK

chemistry
1. what gas law does the nitric oxide relate to and why? (**charles law, boyles law, combined gas or gay-lusaacs law) 2. What gas law does nitrogen monoxide relate to? (**charles law, boyles law, combined gas or gay-lusaacs law)
Monday, October 4, 2010 at 7:52pm by navroz

Chemistry
In accordance with Hess's Law, manipulate the following equations and their change in Hrxn to calculate change in Hrxn's for the reaction HClO4 + NH3 N NH4ClO4... HClO4(aq)+ LiOH(aq) LiClO4(aq)+H2O(l) CH3COOH(aq)+ NH3(aq)  NH4CH3COO(aq) CH3COOH(aq...
Sunday, July 7, 2013 at 3:49pm by Angela

Chemistry
Consider the gas-phase transfer of an electron from a sodium atom to a chlorine atom: Na(g)+Cl(g)-->Na^(+)(g)+Cl^(-)(g) I was able to write the reaction that relates to an ionization energy and that relates to an electron affinity. I broke it up into: Na(g)--> Na^(+)+e...
Saturday, November 3, 2012 at 3:54pm by Ezra

Bus law
Why is the United State a common law country? We're a common law country because we follow precedents established over hundreds of years in Britain and the U.S. Common law is followed except when statutory law opposes a specific practice. Check this site for more information...
Monday, February 19, 2007 at 6:09pm by mike

government
Which branch of the law regulates wrongful acts involving injury to ones person, property, or reputation in a situation not covered by the terms of a contract? A. common law B. tort law C. civil law D. contract law
Thursday, March 8, 2012 at 4:22am by Johana

government
Which branch of the law regulates wrongful acts involving injury to one's person, property, or reputation in a situation not covered by the term of a contract? A. common law B. tort law C. civil law D. contract law
Monday, April 2, 2012 at 8:26pm by Charlette

12 Chemistry
What is the molar enthalpy of combustion of magnesium? This was the lab question that I was asked to find after performing a lab based on Hess' law. I can't find anywhere in my notes how to calculate this, and the text book doesn't explain their steps properly, and I have ...
Saturday, March 29, 2008 at 10:58am by Chase (sorry if this long)

trigonometry
Use logarithms and the law of tangents to solve the triangle ABC, given that a=21.46 ft, b=46.28 ft, and C=3228'30" I have to use logarithms and law of tangents . and then provide the check. which says law of sine or mollweids equation. I can't us the cosine law. If you ...
Saturday, February 26, 2011 at 6:21pm by Anon

Chemistry
Which of the following is the best definition of Hess' Law? A. Heat evolved in a given process can be expressed as the sum of the heats of several processes that, when added, yield the process of interest. B. The enthalpy of a process is the difference between the enthalpy of ...
Monday, May 7, 2007 at 12:45am by Jared

Chemistry - General, Hess's Law
In an experiment, 11.6g of a salt was dissolved in 100.0ml of water contained in the above calorimeter, all at an initial tmperature of 24.5 degrees Celsius. After dissolution was complete, the temperatur was 31.8C. The specific heat of the solution is 3.63J/gxC and the ...
Friday, July 24, 2009 at 6:26pm by Sahar

Chemistry
The molar heat of reaction, H rxn , for the reaction of Ca(s) + 2H+(aq)-> Ca2+(aq) + H2(g) was found to be -550kJ/mol The change Hrxn , for the reaction of CaO(s) + 2H+(aq)-> Ca2+(aq) + H2O(l) was found to be -189kJ/mol Based on these results if the formation of water is...
Saturday, February 21, 2009 at 9:15pm by Anonymous

bus law
What is the chronological order of the major legislation that makes up the history of employment law in this country? For each law, state the social problem the law was designed to address, and discuss how employment law has affected the workplace in the last two decades.
Thursday, September 2, 2010 at 6:32pm by kash

Chemistry
Which of the following is the best definition of Hess' Law? A. Since enthalpy is a state function, it will be different if a reaction takes place in one step or a series of steps. B. Heat is always released by the decomposition of 1 mole of a compound into its constitute ...
Sunday, February 24, 2008 at 7:01pm by Anonymous

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 ...
Wednesday, November 14, 2012 at 9:24pm by marcus

Levy
Given the following data: MnO(s) + H2(g) Mn(s) + H2O(l), H = 100 kJ MnO2(s) + 2 H2(g) Mn(s) + 2 H2O(l), H = –52 kJ use Hess's law to calculate the heat of the reaction MnO2(s) + H2(g) MnO(s) + H2O(l)
Wednesday, January 11, 2012 at 5:46pm by Ari

Chem 121
Use Hess's law and the reactions 1) CH 4(g)+ Cl 2 (g)--->CH 3 CL(g) + HCl (g) 2) CH 3 Cl (g) + Cl 2 (g)---> CH 2 Cl 2 (g) + HCl (g) to determine the enthalpy for the reaction CH4 (g) + 2CH 2 (g)---> CH2 Cl 2 (g) + 2HCl (g)?
Tuesday, March 29, 2011 at 4:49pm by Jessica Jones

Government Law question
What kind of law is it when judges make the law by their decisions on the bench? ___ Law
Monday, January 14, 2013 at 6:15pm by Allyson

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 ...
Friday, January 20, 2012 at 5:58pm by Hannah

business law
No, because the the store did not create a situation that led her to assume that Hall was a sales clerk. Check out page 416 in your Business Law book/
Tuesday, April 12, 2011 at 2:38pm by just a student

Law
Research and identify a labor law that is specific to your state. Share a brief summary of the law with us and discuss why you believe this law is or is not important to the employer-employee relationship.
Friday, November 29, 2013 at 9:48pm by Mattiazz

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