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Unformatted text preview: iffer? 5 Any molecule has 3n-6 vibrational modes where
n = number of atoms present in the molecule. Given that a C=C bond stretch occurs at 1640 cm-1, what value
would you would predict for a CΞC? A. 1405 cm-1.
B. 2115 cm-1. How many vibrational modes would be predicted for
formaldehyde (CH2=O)? 1
frequency (λ in cm) = υ = —
λ A. 3 wave length (λ) B. 6 C. 8 D. 20 E. 32 F. >32 3n-6 = 3(4) – 6 = 6
3 1 9/23/2011 Any molecule has 3n-6 vibrational modes where
n = number of atoms present in the molecule. ΞC-H C-H C=C CΞC =C-H
O-H CO2H C=O 1165 cm-1 1750 c...
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- Spring '08
- Organic chemistry