Chem: Chemical Bond
29) The structural formulas are given for these cis or trans alkenes.
(a) trans-1,2-dichloropropane (b) cis-2-pentene
(c) cis-3-hexene (d) trans-2-hexene
Write the structural formula for:
(a) cis-1,2-dichloropropene (b) trans-2-pentene
(c) trans-3-hexene (d) cis-2-hexene
30) In each case, tell whether cis and trans exist. If they do, write the structural formulas for two isomers and label each cis or trans,
(a) Br2CH2 : No
(b) CH3CH2CH=CHCH2CH3: Yes
(c) CH3CH=CHCH3: Yes
(d) CH2=CHCH2CH3:No
31) Which of these molecules can have cis and trans isomers? For those that do, write the structural formulas of these two isomers and label each cis or trans. For those that cannot have these isomers, explain why.
(a) CH3CH2BrC=CBrCH3
(b) (CH3)2C=C(CH3)2
(c) CH3CH2 lC=ClCH2CH3
(d) CH3ClC=CHCH3
(e) (CH3)2C=CHCH3
32) Oxalic acid has the structural formula.
Is cis-trans isomerism possible for oxalic acid? Explain your answer.
No; Free rotation about the single C-C bond prevents it.
33) 2-methyl propene has the Lewis structure:
Is cis-trans isomerism possible for this oxalic acid?
34) For each pair of bonds, predict which will be the shorter.
(a) B-Cl or Ga-Cl
(b) C-O or Sn-O
(c) P-S or P-O
(d) the C=C or the C=O bond in acrolein H2O=CH-C=OH
35) For each pair of bonds, predict which will be the shorter.
(a) Si-N or P-O
(b) Si-O or C-O
(c) C-F or C-Br
(d) the C=C bond or the C=N bond in acrylonitrile, H2C=CH-C=N
37) Compare the nitrogen bonds in hydrazine, N2H4, and in “laughing gas” N2O. In which molecule is the nitrogen-nitrogen bond shorter? In which should the bond be longer?
38) Consider the carbon-oxygen bonds in formaldehyde, H2CO, or the bond in carbon monoxide, CO. In which molecule is the carbon-oxygen bond shorter?
The bond is shorter in CO
42) Estimate ΔHº for forming 2 mol ammonia from molecular nitrogen and molecular hydrogen. Is this reaction exothermic or endothermic? (N2 has a triple bond.)
-92 kj is the
(a) trans-1,2-dichloropropane (b) cis-2-pentene
(c) cis-3-hexene (d) trans-2-hexene
Write the structural formula for:
(a) cis-1,2-dichloropropene (b) trans-2-pentene
(c) trans-3-hexene (d) cis-2-hexene
30) In each case, tell whether cis and trans exist. If they do, write the structural formulas for two isomers and label each cis or trans,
(a) Br2CH2 : No
(b) CH3CH2CH=CHCH2CH3: Yes
(c) CH3CH=CHCH3: Yes
(d) CH2=CHCH2CH3:No
31) Which of these molecules can have cis and trans isomers? For those that do, write the structural formulas of these two isomers and label each cis or trans. For those that cannot have these isomers, explain why.
(a) CH3CH2BrC=CBrCH3
(b) (CH3)2C=C(CH3)2
(c) CH3CH2 lC=ClCH2CH3
(d) CH3ClC=CHCH3
(e) (CH3)2C=CHCH3
32) Oxalic acid has the structural formula.
Is cis-trans isomerism possible for oxalic acid? Explain your answer.
No; Free rotation about the single C-C bond prevents it.
33) 2-methyl propene has the Lewis structure:
Is cis-trans isomerism possible for this oxalic acid?
34) For each pair of bonds, predict which will be the shorter.
(a) B-Cl or Ga-Cl
(b) C-O or Sn-O
(c) P-S or P-O
(d) the C=C or the C=O bond in acrolein H2O=CH-C=OH
35) For each pair of bonds, predict which will be the shorter.
(a) Si-N or P-O
(b) Si-O or C-O
(c) C-F or C-Br
(d) the C=C bond or the C=N bond in acrylonitrile, H2C=CH-C=N
37) Compare the nitrogen bonds in hydrazine, N2H4, and in “laughing gas” N2O. In which molecule is the nitrogen-nitrogen bond shorter? In which should the bond be longer?
38) Consider the carbon-oxygen bonds in formaldehyde, H2CO, or the bond in carbon monoxide, CO. In which molecule is the carbon-oxygen bond shorter?
The bond is shorter in CO
42) Estimate ΔHº for forming 2 mol ammonia from molecular nitrogen and molecular hydrogen. Is this reaction exothermic or endothermic? (N2 has a triple bond.)
-92 kj is the