Write the mathematical relation between ΔH and ΔU during the formation of one mole of CO2 under standard conditions. - Chemistry

Advertisements
Advertisements
Numerical

Write the mathematical relation between ΔH and ΔU during the formation of one mole of CO2 under standard conditions.

Advertisements

Solution

Formation of one mole of CO2 under standard conditions:

\[\ce{C_{(s)} + O_{2(g)} -> CO_{2(g)}}\]

Δng = (moles of product gases) − (moles of reactant gases)

Δng = 1 – 1 = 0

Now, ΔH = ΔU + ∆ngRT

ΔH = ΔU + 0 × RT

∴ ΔH = ΔU

Concept: Enthalpy (H)
  Is there an error in this question or solution?
Chapter 4: Chemical Thermodynamics - Very short answer questions

APPEARS IN

SCERT Maharashtra Question Bank 12th Standard HSC Chemistry Maharashtra State Board
Chapter 4 Chemical Thermodynamics
Very short answer questions | Q 2

RELATED QUESTIONS

Select the most appropriate option.

The enthalpy of formation for all elements in their standard states is _______.


Select the most appropriate option.

If the standard enthalpy of formation of methanol is –238.9 kJ mol–1 then entropy change of the surroundings will be _______. 


Select the most appropriate option.

Bond enthalpies of H–H, Cl–Cl, and H–Cl bonds are 434 kJ mol–1, 242 kJ mol–1, and 431 kJ mol–1, respectively. Enthalpy of formation of HCl is _______.


Answer in brief.

Obtain the expression for work done in chemical reaction.


Answer the following question.

Calculate standard enthalpy of reaction,

Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g), from the following data.

Δf H°(Fe2O3) = - 824 kJ/mol,

Δf H°(CO) = - 110 kJ/mol,

Δf H°(CO2) = - 393 kJ/mol


Answer the following question.

Calculate ΔU at 298 K for the reaction,

C2H4(g) + HCl(g) → C2H5Cl(g), ΔH = - 72.3 kJ

How much PV work is done?


Answer the following question.

When 6.0 g of O2 reacts with CIF as per 

\[\ce{2ClF_{(g)} + O2_{(g)} -> Cl2O_{(g)} + OF2_{(g)}}\]

The enthalpy change is 38.55 kJ. What is the standard enthalpy of the reaction? (Δr H° = 205.6 kJ)


Answer the following question.

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

CH3OH(l) + `3/2`O2(g) → CO2(g) + 2H2O(l); ΔrH° = - 726 kJ mol-1 

`"C"_("graphite") + "O"_(2("g")) -> "CO"_(2("g"));` ΔrH° = - 393 kJ mol-1

H2(g) + `1/2` O2(g) → H2O(l); ΔrH° = - 286 kJ mol-1


Calculate the work done and comment on whether work is done on or by the system for the decomposition of 2 moles of NH4NO3 at 100 °C
NH4NO3(s) → N2O(g) + 2H2O(g)


Write the expression showing the relation between enthalpy change and internal energy change for gaseous phase reaction.


An ideal gas expands from the volume of 1 × 10–3 m3 to 1 × 10–2 m3 at 300 K against a constant pressure at 1 × 105 Nm–2. The work done is


The work done by the liberated gas when 55.85 g of iron (molar mass 55.85 g mol–1) reacts with hydrochloric acid in an open beaker at 25°C


Define enthalpy of combustion.


Define enthalpy of neutralization.


Enthalpy of neutralization is always a constant when a strong acid is neutralized by a strong base: account for the statement.


Derive the relation between ∆H and ∆U for an ideal gas. Explain each term involved in the equation.


Calculate the enthalpy change for the reaction \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\] from the following data.

\[\ce{2Fe + 3/2O2 -> Fe2O3}\]; ΔH = −741 kJ

\[\ce{C + 1/2O2 -> CO}\]; ΔH = −137 kJ

\[\ce{C + O2-> CO2}\]; ΔH = −394.5 kJ


The standard enthalpies of formation of SO2 and SO3 are −297 kJ mol−1 and −396 kJ mol−1 respectively. Calculate the standard enthalpy of reaction for the reaction: \[\ce{SO2 + 1/2O2 -> SO3}\]


What is standard N ≡ N bond enthalpy from following reaction,

\[\ce{N2_{(g)} + 3H2_{(g)} -> 2NH3_{(g)}; \Delta H^0 = - 83 kJ}\]

\[\ce{ΔH^0_{(H-H)}}\] = 435 kJ; \[\ce{ΔH^0_{(N-H)}}\] = 389 kJ


When 6.0 g of O2 reacts with CIF as per \[\ce{2ClF_{(g)} + O2_{(g)} -> Cl2O_{(g)} + OF2_{(g)}}\] the enthalpy change is 38.55 kJ. The standard enthalpy of the reaction is ____________.


The enthalpy change for two reactions are given by the equations

\[\ce{2Cr_{(s)} + 1.5 O2_{(g)} -> Cr2O3_{(s)}}\];

∆H1 = −1130 kJ ............(i)

\[\ce{C_{(s)} + 0.5 O2_{(g)} -> CO_{(g)}}\];

∆H2 = −110 kJ .........(ii)

What is the enthalpy change, in kJ, for the following reaction?

\[\ce{3C_{(s)} + Cr2O3_{(s)} -> 2Cr_{(s)} + 3CO_{(g)}}\]


In which of the following reactions, ∆H is greater than ∆U?


For the reaction, \[\ce{A_{(s)} + 2B_{(g)} -> 5C_{(s)} + D_{(l)}}\], ∆H and ∆U are related as ____________.


For the reaction, \[\ce{N_{2(g)} + 3H_{2(g)} -> 2NH_{3(g)}}\], ΔH is equal to ______.


In which of the following reactions, ΔH is not equal to ΔU?


The work done during combustion of 9 × 10-2 kg of ethane, C2H6 (g) at 300 K is ______.
(Given R = 8.314 J deg-1, atomic mass C = 12, H = 1)


Calculate ΔU if 2 kJ heat is released and 10 kJ of work is done on the system.


Calculate the work done during the combustion of 0.138 kg of ethanol, C2H5OH(l) at 300 K.
Given: R = 8.314 Jk−1 mol−1, molar mass of ethanol = 46 g mol−1.


Under what conditions ΔH = ΔU?


Calculate ΔS of the surrounding if the standard enthalpy of formation of methanol is − 238.9 kJ mol−1.


In a particular reaction, 2 kJ of heat is released by the system and 8 kJ of work is done on the system. Determine ΔU.


Calculate work done in oxidation of 4 moles of SO2 at 25°C. (Given: R = 8.314 JK−1 mol−1 ).


Define enthalpy.


Share
Notifications



      Forgot password?
Use app×