Q37.The heat of atomization of methane and ethane are 360 kJ mol−1 and 620 kJ mol−1 , respectively. The longest wavelength of light capable of breaking the C −C bond is (Avogadro's number = 6.023 × 1023, h = 6.62 × 10−34 J s) (1) 2.48 × 104 nm (2) 1.49 × 104 nm (3) 2.48 × 103 nm (4) 1.49 × 103 nm
What This Question Tests
This question requires calculating bond energy from atomization data and then using this energy to determine the longest wavelength of light capable of breaking a specific bond.
Concepts Tested
Formulas Used
ΔH_atomization = Σ(bond energies)
E = hc/λ
📚 NCERT Sections This Tests
12.5 — A Hydrogen Atom Initially In The Ground Level Absorbs A Photon,
Physics Class 12 · Chapter 12
12.5 A hydrogen atom initially in the ground level absorbs a photon, which excites it to the n = 4 level. Determine the wavelength and frequency of photon.
12.3 — A Difference Of 2.3 Ev Separates Two Energy Levels In An Atom. What
Physics Class 12 · Chapter 12
12.3 A difference of 2.3 eV separates two energy levels in an atom. What is the frequency of radiation emitted when the atom make a transition from the upper level to the lower level?
3.23 — The Rate Constant For The Decomposition Of Hydrocarbons Is 2.418 × 10–5S–1
Chemistry Class 11 · Chapter 3
3.23 The rate constant for the decomposition of hydrocarbons is 2.418 × 10–5s–1 at 546 K. If the energy of activation is 179.9 kJ/mol, what will be the value of pre-exponential factor.
📋 Question Details
- Chapter
- Thermodynamics & Thermochemistry
- Topic
- Bond energy, Relationship with wavelength
- Year
- 2015
- Shift
- 10 Apr Online
- Q Number
- Q37
- Type
- Numerical
- NCERT Ref
- Class 11 Chemistry Ch 6: Thermodynamics
More from this Chapter
Q89.A heat engine absorbs heat Q1 at temperature T1 and heat Q2 at temperature T2 . Work done by the engine is J (Q1 + Q2). This data (1) violates 1st law of thermodynamics (2) violates 1st law of thermodynamics if Q1 is −ve (3) violates 1st law of thermodynamics if Q2 is − ve(4) does not violate 1st law of thermodynamics
Q93.If at 298 K the bond energies of C −H, C −C, C = C and H −H bonds are respectively 414, 347, 615 and 435 kJ mol−1 , the value of enthalpy change for the reaction H2C = CH2( g) + H2( g) →H3C −CH3( g) at 298 K will be (1) −250 kJ (2) +125 kJ (3) −125 kJ (4) +250 kJ
Q94.In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria (1) (dS)V,E > 0, (dG)T,P < 0 (2) (dS)V:E = 0, (dG)TPP = 0 (3) (dS)V,E = 0, (dG)T,P > 0 (4) (dS)V,E < 0, (dG)T,P < 0
Q96.The enthalpy change for a reaction does not depend upon (1) use of different reactants for the same product (2) the nature of intermediate reaction steps (3) the differences in initial or final temperatures of (4) the physical states of reactants and products involved substances