Advertisements
Advertisements
प्रश्न
Calculate the work done in the decomposition of 132 g of \[\ce{NH4NO3}\] at 100°C.
\[\ce{NH4NO3_{(s)} -> N2O_{(g)} + 2H2O_{(g)}}\]
State whether work is done on or by the system.
Advertisements
उत्तर
Given: Decomposition of 1 mole of NH4NO3
Temperature = T = 100°C = 373 K
To find: Work done and to determine whether work is done on the system or by the system.
Formula: W = −Δ ngRT
Calculation:
Molar mass of NH4NO3 = (2 × 14) + (3 × 16) + (4 × 1) = 80 g mol−1
Moles of NH4NO3 = n = `(132 "g")/(80 "g mol"^-1)` = 1.65 mol
The given reaction is for 1 mole of NH4NO3. For 1.65 moles of NH4NO3, the reaction is given as follows:
\[\ce{1.65 NH4NO3_{(s)} -> 1.65 N2O_{(g)} + 3.30 H2O_{(g)}}\]
Now,
Δng = (moles of product gases) − (moles of reactant gases)
Δng = (1.65 + 3.30) − 0 = +4.95 mol ...(∵ NH4NO3 is in solid state)
Hence,
W = −Δng RT
= − (+ 4.95 mol) × 8.314 J K−1 mol−1 × 373 K
= −15350 J
= −15.35 kJ
Work is done by the system (since W < 0).
The work done is −15.35 kJ. The work is done by the system.
APPEARS IN
संबंधित प्रश्न
Select the most appropriate option.
The enthalpy of formation for all elements in their standard states is _______.
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.
Obtain the relationship between ΔH and ΔU for gas phase reactions.
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)
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 mathematical relation between ΔH and ΔU during the formation of one mole of CO2 under standard conditions.
Write the expression showing the relation between enthalpy change and internal energy change for gaseous phase reaction.
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
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: \[\ce{SO2 + 1/2O2 -> SO3}\]
The standard enthalpy of formation of ammonia is −46.0 kJ mol−1. The enthalpy change for the reaction:
\[\ce{2NH3_{(g)} -> 2N2_{(g)} + 3H2_{(g)}}\] is ____________.
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
The difference between heats of reaction at constant pressure and at constanl volume for the reaction
\[\ce{2C6H6_{(l)} + 15O2_{(g)} -> 12CO2_{(g)} + 6H2O_{(l)}}\] at 25°C in 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 ____________.
When 4 g of iron is burnt to ferric oxide at constant pressure, 29.28 kJ of heat is evolved. What is the enthalpy of formation of ferric oxide?
(Atomic mass of Fe = 56)
In which of the following reactions, ∆H is greater than ∆U?
For the reaction, \[\ce{N_{2(g)} + 3H_{2(g)} -> 2NH_{3(g)}}\], ΔH is equal to ______.
What is the amount of work done when 0.5 mole of methane, CH4 (g), is subjected to combustion at 300 K? (Given, R = 8.314 JK-1mol-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.
Calculate the work done in oxidation of so2(g) at 25°C if, \[\ce{2SO_{2(g)} + O2_{(g)} -> 2SO_{3(g)}}\], R = 8.314 J K−1 mol−1.
Calculate ΔS of the surrounding if the standard enthalpy of formation of methanol is − 238.9 kJ mol−1.
Calculate work done in oxidation of 4 moles of SO2 at 25°C. (Given: R = 8.314 JK−1 mol−1 ).
