Zadania z chemii IB HL

Znalezionych zadań: 37

Filtry i umiejętności2

The cyanide ion acts as a ligand in many complex ions, for example hexacyanoferrate(III), $\ce{[Fe(CN)6]^3-}$

. (i) State the type of bond, as precisely as possible, that joins each cyanide ion to the iron ion. (ii) Deduce the oxidation state of iron in…

Each indicator contains more than one benzene ring. (i) State one functional group, other than the phenyl group, that is present in all three indicators. (ii) Deduce the colour of light absorbed by bromothymol blue in acidic conditions and by bromophenol blue…

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.

Explain how the calibration curve is then used to determine the concentration of $\ce{KMnO4}$ in a reaction mixture of unknown concentration.

Draw a line of best fit on the graph, extrapolating it beyond the range of the data.

State, in mathematical terms, how the absorbance of these solutions depends on their concentration.

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

Deduce the equation that relates absorbance to concentration for these solutions, including the numerical value of the constant.

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