मराठी
महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

Does the following reaction represent a thermochemical equation? CHX4(g)+2OX2(g)⟶COX2(g)+2HX2OX(g), ∆fH° = –900 kJ mol–1 - Chemistry

Advertisements
Advertisements

प्रश्न

Does the following reaction represent a thermochemical equation?

\[\ce{CH_{4(g)} + 2O_{2(g)} -> CO_{2(g)} + 2H2O_{(g)}}\], ∆fH° = –900 kJ mol–1

टीपा लिहा
Advertisements

उत्तर

No, the given reaction does not represent a thermochemical equation. The given standard enthalpy of reaction (∆rH°) indicates the enthalpy change accompanying the reaction when the reactants and products involved are in their standard states. The standard state of water is H2O(l) and not H2O(g).

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 4: Chemical Thermodynamics - Long answer questions

APPEARS IN

एससीईआरटी महाराष्ट्र Chemistry [English] 12 Standard HSC
पाठ 4 Chemical Thermodynamics
Long answer questions | Q 3.3

संबंधित प्रश्‍न

Select the most appropriate option.

Which of the following reactions is exothermic?


Answer in brief.

How will you calculate reaction enthalpy from data on bond enthalpies?


Answer in brief.

What is the standard enthalpy of combustion? Give an example.


Answer the following question.

Calculate ΔrH° for the following reaction at 298 K:

1) 2H3BO3(aq) → B2O3(s) + 3H2O(l), ΔrH° = + 14.4 kJ

2) H3BO3(aq) → HBO2(aq) + H2O(l), ΔrH° = - 0.02 kJ

3) H2B4O7(s) → 2B2O3(s) + H2O(l), ΔrH° = + 17.3 kJ


Calculate the total heat required

a) to melt 180 g of ice at 0 °C

b) heat it to 100 °C and then

c) vapourise it at that temperature.

[Given: ΔfusH° (ice) = 6.01 kJ mol-1 at 0 °C, ΔvapH° (H2O) = 40.7 kJ mol-1 at 100 °C, Specific heat of water is 4.18 J g-1 K-1]


State and explain Hess’s law of constant heat summation.


The enthalpy change of the following reaction:

\[\ce{CH_{4(g)} + Cl_{2(g)} -> CH3Cl_{(g)} + HCl_{(g)}ΔH^0 = –104 kJ}\]

Calculate C – Cl bond enthalpy. The bond enthalpies are:

Bond C − H Cl − Cl H − Cl
∆H°/kJ mol−1 414 243 431

Calculate the standard enthalpy of formation of liquid methanol from the following data:

  1. \[\ce{CH3OH_{(l)} + \frac{3}{2} O_{2(g)} -> CO_{2(g)} + 2H2O_{(l)}}\]     ∆H° = – 726 kJ mol–1
  2. \[\ce{C_{(Graphite)} + O_{2(g)} -> CO_{2(g)}}\]          ∆cH° = – 393 kJ mol–1
  3. \[\ce{H_{2(g)} + \frac{1}{2} O_{2(g)} -> H2O_{(l)}}\]          ∆fH° = – 286 kJ mol–1 

The standard heats of formation for CCl4(g), H2O(g), CO2(g), and HCl(g) are −25.5, −57.8, −94.1 and −22.1 kcal mol−1, respectively.

∆H for the reaction

\[\ce{CCl4_{(g)} + 2H2O_{(g)} -> CO2_{(g)} + 4HCl_{(g)}}\] at 298 K


lf, \[\ce{C_{(s)} + O2_{(g)} -> CO2_{(g)}}\], ∆H = x .........(i)

\[\ce{CO_{(g)} + 1/2O2_{(g)} -> CO2_{(g)}}\], ∆H = y .......(ii)

Then, the heat of formation of CO is:


\[\ce{S + 3/2O2 -> SO3 +2{x} kcal}\] .........(i)

\[\ce{SO2 + 1/2O2 -> SO3 + {y} kcal}\] .......(ii)

The heat of formation of SO2 is ____________.


Which of the following compounds is Not present in its standard state at 25°C and 1 atmosphere pressure?


Given the reaction,

\[\ce{CH2O_{(g)} + O2_{(g)} -> CO2_{(g)} + H2O_{(g)}}\] ΔH = −527 kJ

How much heat will be evolved in the formation of 60 g of CO2?


Combustion of glucose takes place as

\[\ce{C6H12O6_{(s)} + 6O2_{(g)} -> 6CO2_{(g)} + 6H2O_{(g)}}\]; ΔH = −72 kcal mol−1

The energy needed for the production of 1.8 g of glucose by photosynthesis will be ___________.


An ideal gas expands isothermally and reversibly from 10 m3 to 20 m3 at 300 K performing 5 .187 kJ of work on surrounding. Calculate number of moles of gas undergoing expansion. (R = 8.314 J K-1 mol-1)


Which of the following equations has ΔfH° and ΔH° same?


Calculate the standard enthalpy of formation of CH3OH(l) from the following data:

  1. \[\ce{CH3OH_{(l)} + 3/2 O2_{(g)} -> CO2_{(g)} + 2H2O_{(l)}ΔH^° = - 726 kJ mol^{-1}}\]
  2. \[\ce{C_{(s)} + O2_{(g)} → CO2_{(g)}Δ_cH^° = – 393 kJ mol^{-1}}\]
  3. \[\ce{H2_{(g)} + 1/2 O2_{(g)} -> H2O_{(l)}Δ_fH^° = - 286 kJ mol^{-1}}\]

Identify the invalid equation.


What is enthalpy of formation of NH3 if bond enthalpies as (N ≡ N) = - 941 kJ/mol.

\[\ce{(H - H)}\] = 436 kJ/mol and \[\ce{(N - H)}\] = 389 kJ/mol?


Define and explain the term, enthalpy of reaction.


Which of the following reactions defines the enthalpy of formation?


The enthalpy of combustion of S (rhombic) is − 297 kJ mo1-1. Calculate the amount of sulphur required to produce 29. 74 kJ of heat.


Calculate heat evolved for combustion of 13 gm of acetylene (C2H2).

Given: \[\ce{C2H2_{(g)} + 5/2O_{2(g)}-> 2CO_{2(g)} + H2O_{(l)} \Delta_{(c)}H^{0} = - 1300 kJ}\]


Heat of combustion of CH4(g) is -890 kJ/mole. What is the value of Δc H of 8gm of methane?


Calculate the standard enthalpy of combustion of methane if the standard enthalpy of formation of methane, carbon dioxide and water are −74.8, −393.5 and −285.8 kJmol−1 respectively.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×