Zadania z chemii IB HL

A student writing a report on chlorine as a disinfectant collects, from several websites and reference books, values for how much chlorine dissolves in pure water at various temperatures. Source Temperature / °C Solubility of chlorine A 5 1.18 g per 100…

Hypochlorous acid is a weak acid. In water it is in equilibrium with its conjugate base, the hypochlorite ion, $\ce{OCl-}$, which kills microorganisms far less effectively than the acid molecule does. The graph shows what percentage of the dissolved chlorine…

The following burette readings are recorded in one of the titrations. Final burette reading = 26.15 ± 0.05 $\mathrm{cm^3}$ Initial burette reading = 1.15 ± 0.05 $\mathrm{cm^3}$ Calculate the percentage uncertainty in the titre volume.

By drawing a suitable line on the graph, determine the rate at which carbon dioxide is released at the start of Experiment 1. Give your answer in $\mathrm{cm^3\,s^{-1}}$.

Estimate how long after the start of the experiment the piston would first move if a total mass of 750 g were loaded on it.

Use the volumes collected at 120 s in Experiment 1 and Experiment 3 to calculate by what percentage the final volume of carbon dioxide falls for each 100 g added to the piston.

Sketch how the combined mass of the flask, the syringe and their contents would change with time during Experiment 1, and give a reason for the shape of your sketch. Label the axes 'Total mass' and 'Time'.

Chloride ions can act as ligands towards transition metal ions. Three compounds of chromium that differ in the number of chloride ions bonded directly to the chromium ion have the formulas and colours shown. Compound Colour $\ce{[Cr(H2O)6]Cl3}$ violet…

Aqueous solutions of nickel(II) sulfate, which contain $\ce{[Ni(H2O)6]^2+}$ ions, are green. Use section 15 of the data booklet. Which statement explains the colour? A. Green light is absorbed when an electron is promoted between the split 3d orbitals. B.…