Zadania z chemii IB SL

Which methods for separating the components of the given mixtures are correct? Mixture Method I. Two miscible liquids with boiling points of 56 °C and 118 °C Distillation II. The coloured pigments extracted from a leaf Paper chromatography III. A solid…

Describe how the student should prepare this standard solution from the weighed solid using a 250.0 $\mathrm{cm^3}$ volumetric flask.

The student pipetted 25.00 $\mathrm{cm^3}$ of the potassium hydroxide solution into a conical flask and titrated it with nitric acid, $\ce{HNO3(aq)}$, of concentration 0.1250 $\mathrm{mol\,dm^{-3}}$. The burette readings before and after the titration are…

Explain why the potassium hydroxide solution has to be standardized before it is used in the titration. Assume that there are no systematic errors in the procedure.

(i) Suggest one hazard to health or safety in Student A's procedure. (ii) Student A plotted the highest temperature of each mixture against the volume of nitric acid. With a ruler, draw two straight lines of best fit: one following the rising set of points and…

Student B pipetted 30.00 $\mathrm{cm^3}$ of the potassium hydroxide solution into a 150 $\mathrm{cm^3}$ glass beaker and added the nitric acid from a burette in portions of 4.00 $\mathrm{cm^3}$, recording the steady temperature after each addition. Volume of…

Explain why the start line must be horizontal and must be above the level of the solvent when the strip is placed in the chamber.

State the most important property that water must have, with respect to benzoic acid, for it to be a suitable solvent for this recrystallization.

Outline how each of the two by-products is removed from the benzoic acid during the recrystallization. By-product that is almost insoluble in hot water: ... By-product that is much more soluble than benzoic acid: ...