Energetics I
1. This question has 4 part(s).
1.1. This question is about 2-methylpropan-2-ol.
Draw the fully displayed formula of 2-methylpropan-2-ol.
1.2. The mass spectrum of 2-methylpropan-2-ol is shown.
i) The relative molecular mass of 2-methylpropan-2-ol is 74. Give a possible reason why there is no molecular ion peak in the mass spectrum of 2-methylpropan-2-ol.
(1)
ii) Write the formula for a species that could be responsible for the peak at m / z = 59.
(1)
1.3. The equation for the complete combustion of 2-methylpropan-2-ol is
C4H10O (l) + 6O2 (g) → 4CO2 (g) + 5H2O (l)
i) Using the bond enthalpies shown in the table, calculate a value for the enthalpy change, in kJ mol−1, for the complete combustion of 2-methylpropan-2-ol.
(4)
Bond | Mean bond enthalpy / kJ mol−1 |
C–C | 347 |
C–H | 413 |
C–O | 358 |
O–H | 464 |
O=O | 498 |
C=O | 805 |
ii) 2-methylpropan-2-ol burns in air with a smoky flame. Explain how burning with a smoky flame affects the value of the experimentally determined enthalpy change of combustion.
(2)
iii) A Data Book value for the enthalpy change of combustion of 2-methylpropan-2-ol is −2643.8 kJ mol−1. Give the main reason for the difference between this value and your answer to part 8(c)(i).
(1)
1.4. Which observation would be expected when 2-methylpropan-2-ol is heated with potassium dichromate(VI) and dilute sulfuric acid?
Ai এর মাধ্যমে
১০ লক্ষ+ প্রশ্ন ডাটাবেজ
প্র্যাকটিস এর মাধ্যমে নিজেকে তৈরি করে ফেলো
উত্তর দিবে তোমার বই থেকে ও তোমার মত করে।
সারা দেশের শিক্ষার্থীদের মধ্যে নিজের অবস্থান যাচাই
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