At 298 K, the standard enthalpies of formation for C2H2(g)\mathrm { C } _ { 2 } \mathrm { H } _ { 2 } ( g )C2H2(g) and C6H6(l)\mathrm { C } _ { 6 } \mathrm { H } _ { 6 } ( l )C6H6(l) are 227 kJ/mol\mathrm { kJ } / \mathrm { mol }kJ/mol and 49 kJ/mol\mathrm { kJ } / \mathrm { mol }kJ/mol respectively. Calculate ΔH∘\Delta H ^ { \circ }ΔH∘ for
C6H6(l)⟶3C2H2(g)\mathrm { C } _ { 6 } \mathrm { H } _ { 6 } ( l ) \longrightarrow 3 \mathrm { C } _ { 2 } \mathrm { H } _ { 2 } ( g ) C6H6(l)⟶3C2H2(g)
Cell differentiation always involves
(A) the transcription of the myoD gene.
(B) the movement of cells.
(C) the production of tissue-specific proteins.
(D) the selective loss of certain genes from the genome.
Give equations describing the addition–elimination mechanism for the reaction of hexafluorobenzene with sodium methoxide, clearly showing the structure of the rate-determining intermediate.
