Advertisements
Advertisements
प्रश्न
The standard enthalpy of formation of water is - 286 kJ mol-1. Calculate the enthalpy change for the formation of 0.018 kg of water.
Advertisements
उत्तर
Mass of H2O = 0.018 kg = 18 g
Number of moles of H2O = `("Mass of H"_2"O")/("Molar mass of H"_2"O") = (18 "g")/(18 "g mol"^-1)` = 1 mol
The thermochemical equation is,
\[\ce{H_{2(g)} + \frac{1}{2} O_{2(g)} -> H2O_{(l)}}\], ΔfH° = – 286 kJ mol–1
∴ Enthalpy change for formation of 1 mole H2O = - 286 kJ
APPEARS IN
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?
Calculate the standard enthalpy of combustion of CH4(g) if ΔfH°(CH4) = – 74.8 kJ mol–1, ΔfH°(CO2) = – 393.5 kJ mol–1 and ΔfH°(H2O) = – 285.8 kJ mol–1.
Define standard enthalpy of formation.
Define the Bond enthalpy.
Define the Enthalpy of ionisation.
Classify the following into intensive and extensive properties.
Pressure, volume, mass, temperature.
A compound that has a high negative heat of formation is normally ____________.
The volume of oxygen required for complete combustion of 0.25 mole of methane at STP is ______.
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
The standard heats of formation in kcal mol−1 of NO2(g) and N2O4(g) are 8.0 and 2.0 respectively. The heat of dimerization of NO2 in kcal is ____________.
\[\ce{2NO2_{(g)} ⇌ N2O4_{(g)}}\]
The enthalpy change accompanying a reaction in which 1 mole of the substance in the standard state reacts completely with oxygen or is completely burnt is called as ____________.
\[\ce{S + 3/2O2 -> SO3 +2{x} kcal}\] .........(i)
\[\ce{SO2 + 1/2O2 -> SO3 + {y} kcal}\] .......(ii)
The heat of formation of SO2 is ____________.
Enthalpy of formation of two compounds x and y are −84 kJ and −156 kJ respectively. Which of the following statements is CORRECT?
Standard enthalpy of formation of water is - 286 kJ mol-1. When 1800 mg of water is formed from its constituent elements in their standard states the amount of energy liberated is ______.
Heat of formation of ethane, ethylene acetylene and carbon dioxide are - 136, - 66, - 228 and - 395 (all in kJ) respectively, most stable among them is ______.
Calculate the standard enthalpy of formation of CH3OH(l) from the following data:
- \[\ce{CH3OH_{(l)} + 3/2 O2_{(g)} -> CO2_{(g)} + 2H2O_{(l)}ΔH^° = - 726 kJ mol^{-1}}\]
- \[\ce{C_{(s)} + O2_{(g)} → CO2_{(g)}Δ_cH^° = – 393 kJ mol^{-1}}\]
- \[\ce{H2_{(g)} + 1/2 O2_{(g)} -> H2O_{(l)}Δ_fH^° = - 286 kJ mol^{-1}}\]
Calculate the standard enthalpy of:
\[\ce{N2H_{4(g)} + H_{2(g)} -> 2NH_{3(g)}}\]
If ΔH0(N – H) = 389 kJ mol–1, ΔH0(H – H) = 435 kJ mol–1, ΔH0(N – N) = 159 kJ mol–1.
What is the amount of water formed by the combustion of 1.6 g methane?
When the enthalpy of combustion of carbon to carbon dioxide is - 360 kJ mol-1, then the enthalpy change for the formation of 18 g of CO2 from carbon and dioxygen at the same temperature in kJ will be ______.
Calculate the standard enthalpy of the reaction, \[\ce{SiO2_{(s)} + 3C_{(graphite)} -> SiC_{(s)} + 2CO_{(g)}}\] from the following reactions:
- \[\ce{Si_{(s)} + O2_{(g)} -> SiO2_{(s)}}\], ΔrH0 = −911 kJ
- \[\ce{2C_{(graphite)} + O2_{(g)} -> 2CO_{(g)}}\], ΔrH0 = −221 kJ
- \[\ce{Si_{(s)} + C_{(graphite)} -> SiC_{(s)}}\], ΔrH0 = −65.3 kJ
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.
The heat evolved in the combustion of 6.022 x 1021 carbon particles is 3.94 kJ. The heat of combustion of carbon is ______.
Calculate ΔsubH of the H2O from the given data:
\[\ce{H2O_{(s)}->H2O_{(l)},}\] ΔfusH = 6.01kJ mol−1
\[\ce{H2O_{(l)}-> H2O_{(g)},}\] ΔVapH = 45.07 kJ mol−1.
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?
