Date | November 2017 | Marks available | 3 | Reference code | 17N.2.sl.TZ0.4 |
Level | SL | Paper | 2 | Time zone | TZ0 |
Command term | Determine | Question number | 4 | Adapted from | N/A |
Question
Menthol is an organic compound containing carbon, hydrogen and oxygen.
Complete combustion of 0.1595 g of menthol produces 0.4490 g of carbon dioxide and 0.1840 g of water. Determine the empirical formula of the compound showing your working.
0.150 g sample of menthol, when vaporized, had a volume of 0.0337 dm3 at 150 °C and 100.2 kPa. Calculate its molar mass showing your working.
Markscheme
carbon: «0.4490g44.01gmol−1» = 0.01020 «mol» / 0.1225 «g»
OR
hydrogen: «0.1840×218.02» = 0.02042 «mol» / 0.0206 «g»
oxygen: «0.1595 – (0.1225 + 0.0206)» = 0.0164 «g» / 0.001025 «mol»
empirical formula: C10H20O
Award [3] for correct final answer.
temperature = 423 K
OR
«M =mRTpV
«M =0.150g×8.31J K−1mol−1×423K100.2kPa×0.0337dm3=» 156 «g mol–1»
Award [1] for correct answer with no working shown.
Accept “pV = nRT AND n = mM” for M1.