Advertisements
Advertisements
प्रश्न
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?
Advertisements
उत्तर
Given:
Enthalpy change = ΔH = –72.3 kJ
Temperature = T = 298 K
To find:
PV work done and internal energy change (ΔU)
Formulae:
1. W = - ΔngRT
2. ΔH = ΔU + ΔngRT
Calculations:
Δng = (moles of product gases) - (moles of reactant gases)
Δng = 1 – 2 = –1 mol
Using formula (i)
W = - ΔngRT
= - (- 1 mol) × 8.314 J K-1 mol-1 × 298 K
= 2477.57 J = 2.48 kJ
Now, using formula (ii) and rearranging,
ΔU = ΔH - Δ ngRT = ΔH + W = –72.3 kJ + 2.48 kJ = –69.8 kJ
∴ The PV work done is 2.48 kJ.
∴ The internal energy change (ΔU) is –69.8 kJ.
APPEARS IN
संबंधित प्रश्न
Select the most appropriate option.
The enthalpy of formation for all elements in their standard states is _______.
Answer in brief.
Obtain the expression for work done in chemical reaction.
Obtain the relationship between ΔH and ΔU for gas phase reactions.
Calculate the amount of work done in the
1) Oxidation of 1 mole HCl(g) at 200 °C according to reaction.
4HCl(g) + O2(g) → 2Cl2(g) + 2H2O(g)
2) Decomposition of one mole of NO at 300 °C for the reaction
2NO(g) → N2(g) + O2(g)
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.
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
Define enthalpy of combustion.
Enthalpy of neutralization is always a constant when a strong acid is neutralized by a strong base: account for the statement.
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
Identify the equation in which change in enthalpy is equal to change in internal energy.
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)
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)
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.
Under what conditions ΔH = ΔU?
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.
