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प्रश्न
What is the action of heat on potassium permanganate?
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उत्तर
KMnO4 when heated to 473 K, readily decomposes giving oxygen.
\[\ce{2KMnO4 ->[Heat] K2MnO4 + MnO2 + O2}\]
At red heat, potassium permanganate decomposes into potassium manganate (K2MnO3) and oxygen.
\[\ce{2K2MnO4 ->[Red heat] 2K2MnO3 + O2}\]
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संबंधित प्रश्न
Absolute entropies of solids, liquids and gases can be determined by
- Measuring heat capacity of substance at various temperatures
- Subtracting standard entropy of reactants from products
- Measuring vibrational motion of molecules
- Using formula ΔS° = ST° - SO°
Determine whether the reactions with the following ΔH and ΔS values are spontaneous or non-spontaneous. State whether the reactions are exothermic or endothermic.
(a) ΔH = -110kJ, ΔS = + 40JK-1 at 400 K
(b) ΔH = + 40kJ, ΔS = -120JK-1 at 250K
300 M mol of perfect gas occupies 13 L at 320 K. Calculate the work done in joules when the gas expands-
(a) isothermally against a Constant external pressure of 0.20atm.
(b) isothermal and reversible process.
(c) into vaccum until the volume of gas is increased by 3L (R=8.314J mol-1 K-1)
One mole of a gas expands by 3L against a constant pressure of 3 atmosphere. Calculate the work done in -
(a) L.atmosphere
(b) Joules
(c) Calories
Which of the following pairs is an intensive property?
(A) Density, viscosity
(B) Surface tension, mass
(C) Viscosity, internal energy
(D) Heat capacity, volume
55 L atm of work is obtained when 1.0 mole of an ideal gas is compressed isothermally from
a volume of 28.5 L to 18.5 L, the constant external pressure is
(A) 5.05 atm
(B) 5.5 atm
(C) 0.05 atm
(D) 0.55 atm
For a certain reaction, ∆H = − 50 kJ and ∆S = − 80 J K-1, at what temperature does the
reaction turn from spontaneous to non-spontaneous?
(A) 6.25 K
(B) 62.5 K
(C) 625 K
(D) 6250 K
Derive the equation : W = - PextAV
5 moles of helium expand isothermally and reversibly from a pressure 40 × 10-5 N m-2 to 4 × 10-5 N m-2 at 300 K. Calculate the work done, change in internal energy and heat absorbed during the expansion. (R = 8.314 J K-1 mol-1).
