Explain why each of the following names is incorrect (a) 2,2-Dimethyl-6-ethylheptane
(b) 4-Ethyl-5,5-dimethylpentane
(c) 3-Ethyl-4,4-dimethylhexane
(d) 5,5,6-Trimethyloctane
(e) 2-Isopropyl-4-methylheptane

Explanation:

Alkanes are the hydrocarbons in which single bonds are present between the carbon atoms

The suffix for alkane hydrocarbons used is '-ane'. The rules to write the nomenclature of alkanes follows:

Select the longest possible continuous carbon chain and it will be the parent chainNumbering is done as such that the alkyl substituents are given the lowest numberIf different alkyl groups are present, they are written in an alphabetical order irrespective of their position in the carbon chainIf two or more similar alkyl groups are present, the words, di, tri, tetra, and so on are used to specify the number of times alkyl groups appearIf two or more alkyl groups are present and the branching occurs, the numbering is done which gives the minimum possible number to all the substituents

For the given options:

(a) 2,2-Dimethyl-6-ethylheptane

The longest possible carbon chain has 8 carbon atoms (prefix used is 'oct-') and not 7(prefix used is 'hept-').

Thus, the correct IUPAC name will be 2,2,6-trimethyloctane.

(b) 4-Ethyl-5,5-dimethylpentane

The longest possible carbon chain has 6 carbon atoms (prefix used is 'hex-') and not 5(prefix used is 'pent-').

Thus, the correct IUPAC name will be 4-isopropylhexane.

(c) 3-Ethyl-4,4-dimethylhexane

The substituents are not given the minimum possible number. Total sum of the number in original compound = [4 + 4 + 3] = 11

But, if both the methyl groups are placed at 3rd position, then total sum of the number = [3 + 3 + 4] = 10

Thus, the correct IUPAC name will be 4-ethyl-3,3-dimethylhexane

(d) 5,5,6-Trimethyloctane

The substituents are not given the minimum possible number. Total sum of the number in original compound = [5 + 5 + 6] = 16

But, if both the methyl groups are placed at 3rd position and 4th position, then total sum of the number = [3 + 3 + 4] = 10

Thus, the correct IUPAC name will be 3,3,4-trimethyloctane

(e) 2-Isopropyl-4-methylheptane

The longest possible carbon chain has 8 carbon atoms (prefix used is 'oct-') and not 7 (prefix used is 'hept-').

Thus, the correct IUPAC name will be 2,3,5-trimethyloctane

The structures of the compounds are attached below.

Bthe s the

  remember that hf is only the energy of one photon. not two. not three. one.  1) 5.12 * 10^3 photons  find the energy of one photon, then determine how many photons are needed to reach the sensitivity.  e = hf  = (6.626 * 10^-34 js)(5.95 * 10^19 hz)  = 3.94247 * 10^-14 j per photon  (2.02 * 10^-10 j) / (3.94247 * 10^-14 j/photon) = 5123.69149 photons  round to three sig figs.  2) 5.77 * 10^-17 j  energy of pulse = energy per photon * number of photons  = hfn  = (6.626 * 10^-34 js)(1.66 * 10^13 hz)(5250)  = 5.774559 * 10^-17 j  round to three sig figs.  3) 4.07 * 10^8 kj/mol  10^12 pm = 1 m  c = fλ  f = c/λ  e = hf  = hc/λ  = [(6.626 * 10^-34 js)(3.00 * 10^8 m/s) / (2.94 * 10^-12 m)](1 kj/1000 j)(6.02 * 10^23 photons/mol)  = 40702571.4 kj/mol  round to three sig figs.  4) 9.94 * 10^-1 m  e = hc/λ  λ = hc / e  = (6.626 * 10^-34 js)(3.00 * 10^8 m/s) / (2.00 * 10^-25 j)  = 0.9939 m  round to three sig figs.  5) 9.06 * 10^3 photons  energy of pulse = energy per photon * number of photons  number of photons = energy of pulse / energy per photon  = energy of pulse / (hf)  = (3.87 * 10^-13 j) / [(6.626 * 10^-34 js)(6.45 * 10^16 hz)]  = 9055.23695 photons  round to three sig figs.  6) 2.78 * 10^-15 j  this is problem 1, except in reverse.  sensitivity = minumum number of photons * energy per photon  = (5930)(6.626 * 10^-34 js)(7.077 * 10^14 hz)  = 2.78070758 × 10^-15 j  round to three sig figs.