Zadania z chemii IB SL

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: ...

The volume of hot water used to dissolve the crude solid must be chosen carefully. Deduce the effect on the yield or on the purity of the recrystallized benzoic acid of using too much water and of using too little water. Too much water: ... Too little water:…

Describe the setup needed to join the $\ce{Ni^2+}$ | $\ce{Ni}$ half-cell to a second half-cell so that the completed cell lights a bulb.

Suggest why hot-tub owners rarely add bromine itself to the water and instead use solid tablets that release HOBr.

The iron(II) concentration is found by titrating against a standard solution of potassium manganate(VII), $\ce{KMnO4}$. At intervals of a few days, a 20.00 $\mathrm{cm^3}$ sample is withdrawn from each flask and made up to 250.0 $\mathrm{cm^3}$ with water;…