Kemija - 2009./10. jesen - 29.

${\mathrm{C}}_3{\mathrm{H}}_8\mathrm{O}\backslash mathrm\{C\}\_\{3\}\; \backslash mathrm\{H\}\_\{8\}\; \backslash mathrm\{O\}$

${\mathrm{C}}_2{\mathrm{H}}_6\mathrm{O}\backslash mathrm\{C\}\_\{2\}\; \backslash mathrm\{H\}\_\{6\}\; \backslash mathrm\{O\}$

${\mathrm{C}}_2{\mathrm{H}}_4\mathrm{O}\backslash mathrm\{C\}\_\{2\}\; \backslash mathrm\{H\}\_\{4\}\; \backslash mathrm\{O\}$

${\mathrm{C}\mathrm{H}}_4\mathrm{O}\backslash mathrm\{CH\}\_\{4\}\; \backslash mathrm\{O\}$