Zadania z chemii IB HL

Describe how a standard aqueous solution of potassium manganate(VII) can be prepared from the solid.

Describe the steps by which this standard solution is turned into a calibration curve for the colorimeter.

The colorimeter can record either absorbance or percentage transmittance at a chosen wavelength. Outline why one particular wavelength has to be selected.

If the reaction with 0.80 $\mathrm{mol\,dm^{-3}}$ $\ce{HNO3(aq)}$ went to completion, the theoretical mass of $\ce{CO2(g)}$ released would be 1.76 g. (i) Use the graph to determine the mass, in g, of $\ce{CO2(g)}$ actually released in this reaction. (ii)…

(i) Suggest a reason for the slight change in colour observed after the night in the oven. (ii) Suggest how the students could make sure that dehydration in the crucible was complete. (iii) Suggest one way in which the students could reduce the effect of…

Which of the following could be used to follow the progress of the reaction between calcium carbonate and dilute nitric acid? $\ce{CaCO3(s) + 2HNO3(aq) -> Ca(NO3)2(aq) + H2O(l) + CO2(g)}$ I. A balance recording the mass of the open flask and its contents II. A…

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.