Enthalpy

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Questions

• How are enthalpy changes expressed in chemical equations?
• How can enthalpy change be determined for an aqueous solution?
• How does enthalpy change with pressure?
• How do you calculate standard molar enthalpy of formation?
• Why is enthalpy a state function?
• Why is the enthalpy of formation of oxygen zero?
• Why is enthalpy a state function?
• Why can enthalpy not be measured directly?
• How does pressure affect enthalpy?
• How does enthalpy relate to internal energy?
• How does entropy effect enthalpy?
• How does enthalpy change with temperature?
• How does enthalpy differ from heat?
• How does enthalpy affect the spontaneity of a reaction?
• How does enthalpy change differ from heat flow?
• How can I calculate enthalpy of neutralization?
• How can I calculate enthalpy of fusion?
• How can I calculate enthalpy of formation?
• How can I calculate enthalpy of combustion?
• How can I calculate the enthalpy of a reaction?
• How can I calculate the enthalpy change of a reaction?
• Can enthalpy be measured?
• What is an enthalpy diagram?
• What is an example of an enthalpy practice problem?
• What are some common mistakes students make with enthalpy?
• What are some examples of enthalpy?
• What is enthalpy?
• Why is enthalpy an extensive property?
• What mass of hydrogen is required to produce 10,000 kJ of energy?
• Question #b60b5
• Question #7d863
• Question #d2ef3
• Question #36d12
• Question #857fa
• Question #6ea84
• When 9.41 g of phenol, C6H5OH, are burned in a bomb calorimeter at 25 oC, 305.1 kJ of heat are given off. How to calculate the standard enthalpy of combustion, in kJ/mol, of phenol?
• When a cook heats water to make pasta, energy flows _____ the pot of water, so DH is _____. A) into, 0 or B) into, > 0 ?
• What is the standard change in enthalpy of formation of #"MgO"(s)#?
• Question #53c99
• Question #6ecfc
• Question #342e1
• At constant pressure, the combustion of 5.00 g of C2H6 (g) releases 259 kJ of heat. What is ΔH for the reaction? 2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(l)
• Acetylene torches utilize the following reaction: 2 C2H2 (g) + 5 O2 (g) -----> 4 CO2 (g) + 2 H20 (g) How to calculate Delta H in Celsius for this reaction ? Species Delta H C2H2 (g )= +226.7 CO2 (g )= -393.5 H20 (g) = -241.6
• C2H5OH (l) + 3O2(g)->2CO2 (g) + 3H2O (l) Delta H -1367kJ H2 (g) + 1/2 O2-> H2O (l) Delta H -286kJ C(graphite) + O2 (g) -> CO2 (g) Delta H -394 Calculate the change in enthalpy for this equation 2C (g) + 3H2 (g) + 1/2 O2-> C2H5OH (l) Delta H??
• Can someone please explain how to find the amount of energy released in a chemical reaction? What formulas do I use and how do I use them?
• Question #c44c2
• Question #59ed6
• Question #5a15a
• Question #faee7
• Question #8f2d8
• Question #bbfd1
• Question #fcf72
• Question #b7a75
• Question #e1c0b
• Question #0ff54
• Question #536ac
• Question #a82de
• Question #97d3a
• Question #e4ee3
• Calculate the enthalpy of reaction for the reaction #"CH"_3"COOH" + "H"_2"O" -> "CH"_3"CH"_2"OH" + "O"_2#?
• Question #b4e08
• What is the enthalpy change for the following reaction #2SO_(2(g)) + O_(2(g))->2SO_(3(g))#?
• Question #034f0
• Question #71f02
• What is enthalpy?
• Ammonium nitrate + water = enthalpy?
• If a reaction is endothermic what happens to enthalpy, entropy, and gibbs energy?
• Calculate the standard enthalpy change in kJ for the production of 12.2 g of H2O(l) from a reaction with the reactants: H2S(g), O2(g) and the products: H2O(l), SO2(g)?
• How do you calculate enthalpy of vaporization for 1 mole of water?
• What's the unit of enthalpy?
• What is the standard enthalpy of the reaction CO+H2O --> CO2+H2?
• What is an example of entropy? What is an example of enthalpy?
• Why is enthalpy of formation negative?
• Why is enthalpy a state function?
• Question #ca18e
• What is the enthalpy for the reaction Ca(OH)2 (s) + CO2 (g) --> CaCO3 (s) + H2O (l)?
• How would you calculate the standard enthalpy change for the reaction 2A + B = 2C + 2D, if A = -269 B = -411 C = 189 D = -481?
• What is the standard molar enthalpy of combustion of acetic (ethanoic acid)?
• What is the standard enthalpy of formation of methane, given that the average C-H bond enthalpy is 414 kj/mol and the reactions: C(s) -->C(g) H=716 kj/mol 2H2(g)--> 4H(g) H= 872.8 kj/mol?
• How would you calculate the standard enthalpy change for the following reaction at 25 °C: H2O (g) + C (graphite)(s) --> H2 (g) + CO (g)?
• What are the units for enthalpy of reaction?
• What is the enthalpy change for the reaction of 1.000 x 10^2g of nitrogen with sufficient oxygen according to the equation: N2 + O2 -->2NO H=+180.6 kJ?
• What is the enthalpy of the reaction 2CO2 + 3H2O --> C2H5OH + 3O2?
• How would you calculate the enthalpy of formation of the reaction: 4C3H5N3O9 (l) --> 12CO2 (g) +10 H2O (g) + 6N, where delta H = -5678 J?
• Question #59a26
• Question #55342
• What is the difference between standard enthalpy of combustion and standard enthalpy of formation?
• How would you calculate the enthalpy change, delta H, for the process in which 33.3 g of water is converted from liquid at 4.6 C to vapor at 25.0 C? For water: H = 44.0 kJ/mol at 25.0 C and s = 4.18J/g C for H2O(l).
• Does anyone know the value for the standard enthalpy of formation of liquid nitric acid HNO3 ?
• What is the difference between specific heat and enthalpy of formation?
• The lattice energy of CsI(s) is −604 KJ/mol, and the enthalpy of solution is 33 KJ/mol. How would you calculate the enthalpy of hydration (KJ) of 0.65 moles of CsI? Enter a numeric answer only, do not include units in your answer?
• Is the change in enthalpy positive or negative for an exothermic reaction?
• What is the standard enthalpy of C2H2?
• What is the difference between enthalpy and entropy?
• What is the formula used to calculate enthalpy?
• Calculation of enthalpy and entropy of fusion of an unknown solid..?
• Question #0d3d9
• Question #237b1
• What mass of natural gas (CH4) must you burn to emit 263kJ of heat?
• How many kilojoules are released when 111 g of #Cl_2# reacts with silicon in the reaction #Si(s)+2Cl_2(g) ->SiCl_4(g)# #ΔH = - 657kJ?#
• Question #7782e
• Given that #DeltaH_"combustion"^@# for #"propane"# is #-2043*kJ*mol^-1#, what mass of propane is required to give #425*kJ#?
• Question #cafad
• If the heat of combustion for a specific compound is -1160.0 kJ/mol and its molar mass is 84.45 g/mol, how many grams of this compound must you burn to release 427.20 kJ of heat?
• What is the enthalpy of hydrogenation?
• What are all the relevant extensive and intensive thermodynamic quantities?
• Question #556b2
• What is the enthalpy change for the reaction #Br_2 + Cl_2 -> 2BrCl#?
• A sample of ammonium nitrate having a mass of 3.88 grams of water is dissolved in 60.0 g of water. The temperature of the water decreases from 23.0°C to 18.4°C. What is the molar enthalpy of dissolution for ammonium nitrate?
• Question #f11be
• Given the thermochemical equation #2SO_2+O_2 ->2SO_3#, #ΔH°_(rxn)# #= - 198 # #kJ#, what is the standard enthalpy change for the decomposition of one mole of #SO_3#?
• When 0.560 g of #Na#(s) reacts with excess #F_2#(g) to form #NaF#(s), 13.8 kJ of heat is evolved at standard-slate conditions. What is the standard enthalpy of formation?
• Concerning the reaction #C + O_2 -> CO_2#, if the #ΔH° = -393# #kJ#/#mol#, how many grams of #C# must be burned to release #275# #kJ# of heat?
• Question #4416b
• Question #fe987
• If the heat of combustion for a specific compound is -1220 kJ/mol and its molar mass is 78.35 g/mol, how many grams of this compound must you burn to release 649.90 kJ of heat?
• Question #04705
• Question #b63ca
• What is "electron-gain" enthalpy?
• Question #05692
• Question #fdbbc
• Question #cf988
• Question #a239e
• Question #42d59
• Question #69013
• In the reaction #B_2H_6(g) + 3O_2(g) -> B_2O_3(s) + 3H_2O(g), ΔH = -2035 kJ#, how much heat is released when a mixture of #4.65# #g# #B_2H_6# and #2.94# #g# #O_2# is burned?
• What is the relationship between enthalpy and internal energy? Where does #q = DeltaH# come from?
• Question #758fd
• For the reaction #"B"_2"H"_6(g) + 6"Cl"_2(g) -> "B"_2"Cl"_6(g) + 6"H"_2(g)#, if #"0.252 mols Cl"_2# reacts with #"0.111 mols B"_2"H"_6#, and #DeltaH_(rxn)^@ = -"1396 kJ"#, what is the heat of reaction?
• Question #44af5
• The heat of vaporization of water is 540 cal/g. How many calories would be needed to convert 3 moles of water to vapor?
• How many joules of heat energy are required to change 64 grams of methane from a liquid to a gas at constant temperature and pressure?
• Why are high heats of vaporization usually associated with high boiling temperature?
• Carbon and oxygen react to give carbon dioxide. The reaction of 4.49 g #C(s)# with 9.21 g #O_2(g)#releases 113.2 kJ of heat. What is the enthalpy of formation of #CO_2(g)#?
• Question #c05c3
• Question #ce200
• Question #dbcb5
• Question #bea74
• Question #7aa26
• Question #56be2
• Question #69992
• How much energy is released when 14.0 g of carbon monoxide are completely combusted?
• Question #284c0
• Question #a11ba
• Question #d0e3c
• Question #275b6
• How much heat is required to warm 1.30 kg of sand from 30°C to 100°C?
• Question #cd6d2
• Question #ec791
• How do I assess the enthalpy of a combustion reaction, when MORE than one mole of hydrocarbon is combusted?
• How do we formulate #DeltaH_f^@# for #"carbon tetrachloride"#, and #HCl#?
• Question #de5b9
• Question #1a163
• If 150 grams of water is heated from 200°C to 0°C, how many joules of heat energy are absorbed?
• Question #88b71
• Question #f7a41
• An exothermic reaction releases 80.5 J of energy. How many calories of energy are released in the reaction?
• Acetylene is used in blow torches, and burns according to the following equation: 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) Use the following information to calculate the heat of reaction:?
• The rocket fuel hydrazine, #"N"_2"H"_(4(g))#, is formed by the reaction: #2"H"_(2(g)) + "N"_(2(g)) -> "N"_2"H"_(4(g))# The heat of reaction for this process is #"95.40 kJ/mol"#?
• Question #8697a
• Question #495b7
• Consider the following reaction: #"P"_(4(s)) + 10"Cl"_(2(g)) -> 4"PCl"_(5(g))#, #DeltaH =-"1776 kJ"#, what is the standard enthalpy of formation for #"PCl"_5#?
• If a reaction for the combustion of ethanol has a -29.7KJ/g, what is the molar heat of combustion?
• Write the reaction which has a heat of reaction equal to heat of formation for HCl(g) ?
• Consider the reaction 2 Al2O3(s) -> 2 Al(s) + 3 O2(g). The heat of formation of aluminum oxide is -1669.8 kJ/mol. Calculate the heat of reaction?
• How do you find delta h in a thermochemical equation?
• How do you find delta h of a chemical equation?
• Use the following bond enthalpies to calculate the heat of reaction?
• Question #fbc22
• What is the enthalpy of hydrogenation of propene?
• For the reactions, H2(g)+Cl2(g)----->2HCl(g)+xKJ H2(g)+Cl2(g)----->2HCl(l)+yKJ Which one of the following statement is correct? A)x>y B)x<y C)x=y D)more data required
• Question #f4c22
• If a piece of aluminum is heated from 30.0°C to 50.0°C, what is the value of ∆T?
• Which of the following has highest bond enthalpies? H-F C=O H-H N(triple bond)N
• Why is the [specific] heat capacity of water high?
• What is the heat of formation of water in kcal mol?
• What is the heat of formation of water in kj/mol?
• What is the heat of formation of water vapor?
• How does specific heat capacity of water protect living organisms?
• How does the exceptional heat capacity of water affect climate on earth?
• How can you find heat of formation of water?
• What is the molar heat of formation of water?
• What is the standard enthalpy of formation of water vapor?
• Why is the heat capacity of water important?
• What is the equation for the calculation of heat of fusion?
• What is the formula for latent heat energy?
• What is the formula for #DeltaH_"fus"#?
• Question #356d2
• Can you give examples of exothermic reactions?
• Given the following data, what is the enthalpy associated with the reaction? #(i)# #3H_2(g) + O_3(g) rarr 3H_2O(g)#; #DeltaH_"rxn"=??#
• Question #1556c
• Consider the reaction: #2ClF_3 (g) + 2HN_3(g) -> N_2(g) + 6HF(g) + Cl_2(g)#. When calculating #DeltaH^(o)rxn#, why is the #DeltaH_f^o# for #N_2# not important?
• The #DeltaH# value for the reaction #1/2O_2 (g) + Hg(l) -> HgO (s)# is -90.8 kJ. How many kJ are released when 66.9 g #Hg# is reacted with oxygen?
• Is the following reaction endothermic or exothermic? #Ca_((S)) + 2C_(s) -> CaC_(2(S)) + 62.8 kJ#?
• What is enthalpy a form of?
• Methane, #CH_4#, reacts with oxygen to produce carbon dioxide, water, and heat. #CH_4(g) + 2O_2(g) -> CO_2(g) + 2H_2O(l)#; #DeltaH = -890.3 (kJ)/(mol)#. What is the value of #DeltaH# if 7.00 g of #CH_4# is combusted?
• Why can't ice transfer coldness into another substance?
• When 10.0 g of ammonium nitrate is dissolved in 100 cm3 of water, the temperature of the solution decreases from 19.0°C to 10.5°C, how do I solve the following?
• Why is it when using bond enthalpies to calculate enthalpies of reaction, they are not always accurate and enthalpies of formation are preferred?
• Is mass intensive or extensive?
• Is pressure an extensive or intensive property?
• Question #3ae78
• If given #2C_4H_10 (g) + 13O_2 (g) -> 8CO_2 (g) + 10H_20 (g)# and #DeltaH# = -5750 kJ. How do you determine the molar enthalpy of combustion of butane?
• When thermochemical data are quoted, often the units are #DeltaH*mol^-1#. In the photosynthesis reaction, why is #DeltaH_"rxn"^@=2800*kJ*mol^-1#?
• Question #ea30d
• A 0.25 g sample of a pretzel is burned. The heat it gives off is used to heat 50 g of water from 18°C to 42°C. What is the energy value of the pretzel, in kcal/g?
• Question #26819
• What is the enthalpy change when #"5 g"# of #Y# are dissolved in #"100 g"# of water to decrease its temperature from #22^@ "C"# to #17^@ "C"#? #C_P = "4.184 J/g"^@ "C"# for pure water near #25^@ "C"#.
• Question #9bc2f
• Given #N_2(g) +3H_2(g) rarr 2NH_3(g)+92*kJ#...what energy is associated with the formation of #A.# #"4 moles of ammonia"#; and #B.# #"4 g ammonia is produced"#?
• Given... #N_2(g) + 3H_2(g) rarr 2NH_3(g) + 92.4*kJ#... ..what is #DeltaH_f^@# #NH_3(g)#?
• How does the bond energy for the formation of #"NaCl"(s)# take place? Please explain in steps comprehensively but concisely. Thank you in advance.
• Question #18ac5
• Question #65c16
• Question #da5d4
• Question #a6cdc
• Question #03c5e
• How would you use a standard enthalpies of formation table to determine the change in enthalpy for these reactions?
• A reaction is exothermic and spontaneous. Is the change in entropy of the process positive, negative, or zero? Or can it not be determined from the information given?
• What is the difference between enthalpy of formation, combustion, solution, and neutralization?
• Question #37c52
• The heat of combustion for #n#-heptane, #C_7H_16#is 4,817 kJ/mol. How much heat is released if 550 kg of this liquid burns completely?
• If the temperature of 1 gram of water changes from 22°C to 27°C, how many calories of heat were involved? How many joules?
• What is the change in internal energy of reaction when #"0.721 g"# of titanium is placed into a bomb calorimeter and allowed to combust, if the temperature rises from #25^@ "C"# to #53.8^@ "C"#? #C_"cal" = "9.84 kJ/K"#.
• Question #7fabf
• Question #dc88f
• How do you calculate the molar enthalpy of condensation (#DeltaH_(cond)#) for ammonia when 100.0 g of #NH_3# gas turn into a liquid at its boiling point?
• Question #2add8
• At #100^@ "C"# and #"1.00 atm"#, the molar volume of water vapor is #"30.6 L/mol"# and the enthalpy of vaporization is #"40.66 kJ/mol"#. What is the change in internal energy at this temperature for #"1 mol"# of water? (#rho("H"_2"O"(l)) ~~ "996 g/L"#)
• Question #ff017
• Calculate the enthalpy of formation of acetic acid if its anthalpy of combustion to CO2 and H2O is - 867 kJ/mol and the enthalpies of formation of CO2 and H2O are respectively - 393.5 and -285.9 kJ / mol ?
• When you add 0.857 g of sodium metal to an excess of hydrochloric acid, you find that 8910 J of heat are produced. What is the enthalpy of the reaction?
• How to do you find delta H?
• Question #c1b62
• Question #132b8
• How does energy evolve in the INCOMPLETE combustion of benzene...?
• What is #DeltaH_f^@# for #NO(g)#?
• Question #0d7fc
• Question #0314e
• How do we represent the complete (and incomplete) combustion of benzene?
• What is the standard enthalpy of the combustion of ethene?
• Given the combustion of silane... #SiH_4(g)+2O_2(g)rarrSiO2(s)+2H_2O(g); DeltaH=−1429⋅kJ⋅mol^(−1)#.. How much heat will evolve given combustion of #15.7*g# quantity?
• Question #295d0
• Question #3c373
• What is the standard enthalpy of formation for ethanol #C_2H_5OH#?
• Question #6fd64
• How would you calculate the amount of heat transferred when 3.55 g of Mg(s) react at constant pressure? How many grams of MgO are produced during an enthalpy change of -234 kJ?
• How do you calculate the enthalpy change for the reaction #2C_8H_18(l) + 17O_2(g) -> 16CO(g) + 18H_2O(l)#? #DeltaH^o"_(rxn) =?#
• How much heat i released to the environment as 245 g of steam at 140°C is cooled to -15°C?
• What is the free energy for the dissolution of solid sodium chloride in water at 25C?
• 1.21 g of ethanol, #C_2H_5OH#, was burned in a spirit burner. The heat produced raised the temperature of 400 g of water placed in a beaker above the flame from 17.0 °C to 29.9 °C. How do you calculate the enthalpy change for the reaction taking place?
• What is the enthalpy of reaction in #"kJ/mol"# for when #"0.254 g"# of #"Mg"# is dropped into a coffee-cup calorimeter, if the temperature of #"200. mL"# of water rose from #25.00^@ "C"# to #32.20^@ "C"#?
• What are #"lattice"# and #"hydration energies"#?
• How much energy does the oxidation of 6.03 L of nitrogen absorb?
• Question #ce902
• For the gas-phase reaction #"OF"_2(g) + "H"_2"O"(g) -> "O"_2(g) + 2"HF"(g)#, the nonzero enthalpies of formation are #23.0#, #-241.8#, and #-"268.6 kJ/mol"#, respectively. What are the #DeltaH_(rxn)^@# and #DeltaU_(rxn)^@# in #"kJ/mol"#?
• How do you determine the enthalpy change for the reaction below using the enthalpy of combustion data in the table: #3C_((s)) +4H_(2(s)) -> C_3H_(8(s))#?
• What is the standard enthalpy change of the formation of water?
• What is the standard enthalpy change of combustion of ethane?
• In an experiment at constant pressure, 4.24g of lithium chloride is dissolved in 100. mL of water at initial temperature of 16.3 degrees C. The final temperature of the solution is 25.1 degrees C. What is the enthalpy of solution in kJ/mol?
• Question #e273b
• Question #fb528
• What is the standard enthalpy of atomization?
• How does enthalpy vary with pressure? Doesn't it increase at higher pressure?
• How do you calculate the enthalpy change in the following reaction #4NH_3(g) + 5O_2(g) -> 4NO(g) + 6H_2O#?
• Question #ac0af
• How do I calculate ΔHrxfollowing reaction? CaO(s)+CO2(g)→CaCO3(s) Use the following reactions and given ΔH values: Ca(s)+CO2(g)+1/2O2(g)→CaCO3(s), ΔH= -812.8 kJ 2Ca(s)+O2(g)→2CaO(s), ΔH= -1269.8 kJ Express your answer using four significant figures.
• Question #73593
• What is the change in internal energy for the combustion of #"1.320 g"# of a hydrocarbon in a bomb surrounded by #"2.55 L"# of water if the temperature rises from #20.00^@ "C"# to #23.55^@ "C"#? Assume the heat capacity for the dry device is #"403 J/K"#.
• Question #9151b
• Question #669dc
• Question #8dedd
• Given #H_2+Delta rarr 2dotH# #;DeltaH=104*kcal*mol^-1#, what is #DeltaH_f^@# for #dotH(g)#?
• What do we mean by the 'enthalpy' of a chemical bond? How does it help us to know whether a reaction will be endothermic (take in heat energy from the environment) or exothermic (release heat energy to the environment)?
• Question #8148d
• What if I am not given the initial or final temperature, only the change in temperature? Can I still calculate for the heat flow?
• Question #27cd4
• Question #a1bda
• Question #c63e6
• Question #4b204
• Question #98e63
• Why is the combustion of methanol an exothermic reaction?
• What is Hess's Law?
• What is the difference between #"atomization energy"# and #"bond dissociation energy"#?
• What describes the enthalpy of formation of a substance?
• What symbol is used to represent enthalpy?
• #DeltaH_"combustion"^@# #"propane"=2220*kJ*mol^-1#. What mass of propane is required to yield #76000*kJ# of energy?
• Question #90093
• How can we convert #DeltaH_f^@# at 298K to #DeltaH_f^@# at different temperatures ?? Also tell how to convert bond energy at 298K to bond energy at different temperature
• Given #DeltaH_"combustion"^@# for butane is #-2657*kJ*mol^-1#, what is #"heat of combustion"# for butane in #J*g^-1#?
• What is the #DeltaH_f^@# of liquid water ? Show calculation with bond energies
• How do you solve the heat equation?
• Question #010d4
• What is the enthalpy change of reaction for this reaction?
• Question #f8e22
• How do you determine the amount of heat (in kJ) given off when #1.26 xx 10^4# g of ammonia are produced according to the equation #N_2(g) + 3H_2(g) -> 2NH_3(g)#, #DeltaH°_(rxn)# = -92.6 kJ/mol?
• Question #85b26
• Question #a99e5
• For the reaction #"N"_2(g) + "O"_2(g) -> 2"NO"(g) + "114.14 kJ"#, what mass of #"NO"# would need to be produced in order to release #"5.25 kJ"# of heat?
• Question #6a733
• How can we find #DeltaH_"rxn"^@# for...? #NaOH(s) + HCl(g) rarr NaCl(s) + H_2O(l)#?
• Question #ae5d8
• How is #DeltaH_(fusion)# used to calculate the mass of solid that 1kJ of energy will melt?
• Question #26832
• What is #DeltaH_f^@# for ammonia, and how is it formulated?
• What are the signs of the enthalpy and entropy for the vaporization of acetone?
• Given the following data, what is the enthalpy associated with the given equation? ##
• Question #b773e
• Some drag-racing vehicles burn methanol, as presented by the following equation. What the mass of methanol that burns to produce an enthalpy change of #-9.00 xx 10^4# kJ?
• How would you calculate #DeltaH^@# for the following reaction: #Br_2(g) -> Br_2(l)#?
• Question #c845f
• How do you calculate the standard enthalpy of reaction, #DeltaH_(rxn)^@# for the following reaction from the given standard heats formation (#DeltaH_f^@#) values: #4NH_3(g) + 5O_2(g) -> 4NO(g) + 6H_2O(g)#?
• Question about equation for lattice energy?
• How much propane is required to power the stove that heats and vaporizes this water? What was the efficiency?
• Question #b4781
• Question #899a4
• How much energy is generated from freezing 2.5 g of water?
• Question #7e12c
• Question #d9ce7
• How are #DeltaH_"reaction"^(@)# assessed?
• The standard enthalpy of reaction, #DeltaH^@"_(rxn)#, for the reaction #NH_3(g) + HCl(g) -> NH_4Cl(s)# is -39.65 kJ. How do you determine the value of #DeltaE^@"_(rxn)# for this reaction at 298 K?
• Question #751ec
• Question #ad2cf
• Question #df8e1
• Question #eb3dd
• Calculate the change in enthalpy #( DeltaH)# for the chemical reaction modeled by this chemical equation: #H_2 + Cl_2 rarr 2HCl# Is energy entering or leaving the system? How do you know? What happens to the covalent bonds during this reaction?
• How much heat is lost when a 640 g piece of copper cools from 375°C to 26°C?
• For the aqueous reaction of #"100 mL"# of #"0.50 M"# ammonia with #"300 mL"# of #"0.50 M"# hydrochloric acid to form ammonium chloride, if #"HCl"# is in excess, and the solution heated up by #"1.6 K"#, what is the enthalpy of reaction?
• What if soot (unburned carbon) accumulated on the bottom on the small can? would this produce a greater or a lower heat value than expected?
• Write out the balanced reactions for combustion of methanol, ethanol, propanol, butanol, and pentanol?
• How much heat energy must be absorbed to completely melt 35.0 grams of #H_2O#(s) at 0°C?
• Question #71b3e
• What is the term used for a well insulated reaction vessel used to measure delta H of reactions?
• Calculate the enthalpy of dissolution in #"kJ/mol"# of #"NaOH"#?
• A 445 g sample of ice at -58°C is heated until its temperature reaches -29°C. What is the change in heat content of the system?
• Question #01551
• Using Hess's law, determine the enthalpy change for the overall reaction?
• Question #5034d
• Question #414d3
• How many joules are needed to boil 59.8 g of ethanol if the heat of vaporization is 854 J/g?
• Using the chemical equation below, determine the energy released by burning 2 moles of propane, #"C"_3"H"_8#? a) 4438.4 kJ b) 11096 kJ c) 2219.2 kJ d) 1109.6 kJ
• Question #460c8
• Question #4b921
• Question #302ef
• What is the equation for the reaction that represents the mean #"C-F"# bond energy in carbon tetrafluoride?
• Enthalpy question?
• Thermochemistry?
• Given the reaction: #NaOH(s) + H_2O(l) -> Na^"+"(aq) + OH^"-" (aq) + 10.6 kJ#, the heat of reaction, #ΔH#, is (positive/negative), the entropy, #ΔS#, is (positive/negative) and the reaction is (spontaneous/not spontaneous). Thermochem?
• Given the following reactions the enthalpy of reaction for 2N2O(g) --> 2NO(g) +N2(g) is __________ kJ? N2 (g) + O2(g) --> 2NO(g) ΔH = +180.7 kJ 2N2O(g) --> O2 (g) + 2N2(g) ΔH = -163.2 kJ
• The value of DH0 for the reaction below is #-6535# kJ. __________ kJ of heat are released in the combustion of #16.0# g of #C_6H_6#(l)? 2C6H6(l) + 15O2 (g) --> 12CO2 (g) + 6H2O(l)
• What are the total enthalpy changes for each of the following oxidation or reduction processes?
• How much energy is needed to vaporize 5.00 g of water?
• How much energy is needed to raise the temperature of 2.0 g of water by 5.0°C?
• Question #903e4
• Question #d857d
• How do you equate heat of reaction to heat of formation?
• Question #578de
• Given....#2Mg(s) + O_2(g) rarr 2MgO(s)# #; DeltaH_"rxn"=-1203*kJ*mol^-1# What enthalpy is associated with the combustion of FOUR moles of magnesium metal?
• The heat content of a system is equal to the enthalpy only for a system that is at constant what?
• NaCl has a #DeltaH_(fus)# = 30.2 kJ/mol. What is the mass of a sample of NaCl that needs 732.6 kJ of heat to melt completely?
• Question #17866
• How do we represent the reduction of dinitrogen?
• Why is it that in order to convert the change in enthalpy per mole of product into the change in enthalpy per gram of the same product, you need to divide the change in enthalpy by the molar mass? Can you provide an example, please?
• Can you compare the lattice enthalpies of the salts #MgCl_2#, and #CaCl_2#, and #SrCl_2#, and #BaCl_2#?
• Find ΔErxn for the reaction in kJ/mol hexane. The heat capacity of the bomb calorimeter, determined in a separate experiment is 5.79 kJ/∘C ?
• If the heat of combustion for a specific compound is -1110.0 kJ/mol and its molar mass is 89.45 g/mol, how many grams of this compound must you burn to release 834.20 kJ of heat?
• Why is the heat of hydrogenation of benzene less than expected?
• Determine the masses of titanium and iodine that react if #1.66xx10^3# #"kJ"# of heat is emitted by the reaction?
• Given the ammonia synthesis: #N_2(g) + 3H_2(g) rarr 2NH_3(g)# #DeltaH_"rxn"^@=-92.6*kJ*mol^-1#, what reaction enthalpy is associated with the formation of #8.55xx10^4*g# of ammonia?
• What is the amount of energy required to raise the temperature of 1 g of water 1°C?
• What is the enthalpy associated with the formation of two moles of #NO(g)#?
• Thermochemical Analysis of Trinitroglycerin?
• How do I calculate the standard enthalpy of formation (ΔH∘f) for nitromethane?
• A chemical engineer studying the properties of fuels placed 1.820 g of a hydrocarbon in the bomb of a calorimeter and filled it with O2 gas. What was the heat of the reaction for the combustion per gram of the fuel?
• How many grams of C2H4 must burn to give 84.0 kJ of heat?
• How do I calculate the ΔH this reaction?
• Question #51bcc
• When 150 g of ammonium nitrate dissolves in 450 g of water, the temperature of the solution decreases from 22 °C to 6.9 °C. What is the enthalpy of solution in joules per gram of ammonium nitrate?
• Question #24eab
• What do we call the energy evolved when a gaseous metal cation is hydrated by bulk water?
• Using the balanced equation shown below, what is the mass of C3H8 that must react in order to release 1.25×10^6 kJ of heat? ΔHrxn = –2219.9 kJ
• How would I know the enthalpy of formation of barium carbonate on an exam?
• What is the #DeltaH_(rxn)^@# for the following reaction if 70.4 kJ of energy is absorbed when 28.2L of NO (g) is produced at STP? #2 NO_2 (g) -> 2 NO (g) + O_2 (g)#
• When ammonium chloride dissolved in water the temperature decreases. The energy change for the dissolution of ammonium chloride is #+284Jg^-1# ?
• 50mL of 1 mole of HCI was added to 50mL of 1 mole NaOH. What temperature change would be noticed?
• Question #d203d
• Find the ΔH° for the reaction? a) Fe2O3(s)+3CO2(g)→2Fe(s)+3CO2(g)
• Question #55fec
• Hello there! I think I would need some help for this one. Can you try helping me out please ? Thanks!
• How much energy is required to vaporize 3210 g of water at 100 °C ?
• I have read that when metal like Na, K, Be put into water , heat is evolved. Can we call this heat of hydration? Please let me know what is heat of hydration actually?
• The standard heat of formation of Fe2O3(s) is 824.2kJ/mol. Calculate heat change for the reaction 4Fe(s)+3O2(g)=2Fe2O3(s)?
• Can you explain the notation of enthalpy and how it is denoted and used? Very confused at the moment :/
• Question #75fed
• What is the change in enthalpy for the final reaction?
• Question #88aee
• Question #67549
• Question #3b059
• Considering the reaction shown below, how much thermal energy would be required to run the reaction with 5.0 g of hydrogen and 25 g of iodine?
• Question #f776d
• Question #60074
• The temperature of a #"15-mL"# strong acid solution increases by #2^@"C"# when #"15 mL"# of a strong base is added. By how much should the temperature increase if #"5 mL"# of each are mixed?
• What is the standard enthalpy of formation of SO2(g)?
• What is the enthalpy change for the reaction?
• When 2 moles of #H_2(g)# and 1 mole of #O_2(g)# react to give liquid water, 572 kJ of heat evolve. #2H_2(g)# + #O_2(g)# #rarr# #2H_2O(l)# ; #DeltaH# = -572 kJ a) What is the themochemical eq. for 1 mole of liquid water?
• Calculate the amount of heat evolved in the complete oxidation of #"8.17 g"# of #"Al"# #(M_M = "26.98 g/mol")# at #25^@"C"# and #"1 atm"# pressure?