Zadania z chemii IB HL

Estimate the absorbance of a 0.400 $\mathrm{mol\,dm^{-3}}$ solution of nickel(II) sulfate.

Predict the difference, if any, between the absorbance of the 0.400 $\mathrm{mol\,dm^{-3}}$ solution read from the extrapolated line and the value calculated from the equation in 3d.

Each student used a different mass of the hydrated salt. The results of the whole class are shown below ($M_r$ of $\ce{H2O}$ = 18.02). Student Mass of $\ce{CuSO4 * XH2O}$ / g Mass of $\ce{CuSO4}$ / g Loss in mass / g Amount of $\ce{CuSO4}$ / mol Amount of…

Calculate the mass of solid potassium hydroxide that has to be weighed out.

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…

Using the concentration determined in 1c and the intended concentration of 0.1500 $\mathrm{mol\,dm^{-3}}$, calculate the percentage error in the concentration of the potassium hydroxide solution. If you have no value from 1c, take the concentration to be…

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.

The student then used the potassium hydroxide solution standardized in 1c to titrate ethanoic acid, $\ce{CH3COOH}$, whose concentration was not known. (i) Neutralizing 25.00 $\mathrm{cm^3}$ of the acid required 40.00 $\mathrm{cm^3}$ of the standardized…