Zadania z chemii IB HL

Deduce, giving a reason, which of the two dyes, orange or violet, is the more polar.

The student suspected that the ink contained more than four dyes, and that one of the spots was two dyes that had not separated. Suggest how the student could modify the chromatography experiment to test this idea.

Explain how the dyes are separated from one another in paper chromatography.

Methanoic acid, $\ce{HCOOH}$, is a weak acid, and solutions of it are often used as acidic buffers. A chemist prepared a $0.500\ \mathrm{mol\,dm^{-3}}$ solution of methanoic acid, in which two conjugate acid–base pairs are present. (i) For each pair, state the…

(i) Oil of vitriol, spirit of hartshorn and wood alcohol are old trivial names still occasionally used for chemical substances, and names like these can be a source of confusion in international scientific communication. Outline how the modern system of naming…

(i) Concentrated sulfuric acid, $\ce{H2SO4}$, is used as the catalyst in the manufacture of propyl ethanoate. Explain how the catalyst affects the reaction. (ii) The conversion of propane into 1-bromopropane, $\ce{C3H8(g) + Br2(g) -> CH3CH2CH2Br(g) + HBr(g)}$…

(i) Calculate the enthalpy change, $\Delta H$, for the overall synthesis of propyl ethanoate from propane and ethane shown above. Use section 12 of the data booklet. (ii) Two students each calculated the enthalpy change for the reaction between propan-1-ol and…

(i) To check the value of $K$ found in (d)(viii), a student set up an experiment: 0.500 mol each of propan-1-ol and ethanoic acid were mixed with a small amount of concentrated sulfuric acid at 25 °C, and the mixture's volume was kept constant throughout.…