Zadania z chemii IB HL

Nickel(II) sulfate solution is green. Deduce the most suitable wavelength for this colorimetry, using section 15 of the data booklet.

In the first step, manganese(III) ions formed from the manganate(VII) are complexed by ethanedioate ions. $\ce{[Mn(H2O)6]^3+(aq) + 2C2O4^2-(aq) -> [Mn(C2O4)2(H2O)2]^-(aq) + 4H2O(l)}$ (i) Deduce the oxidation state of carbon in $\ce{[Mn(C2O4)2(H2O)2]^-}$. (ii)…

An aqueous solution of nickel(II) sulfate, which contains the $\ce{[Ni(H2O)6]^2+}$ ion, is green. Which statement explains the origin of this colour? A. Red light is absorbed when electrons are promoted between the split d orbitals of the nickel ion. B. Red…

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…

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…

4.06 g of hydrated magnesium chloride, $\ce{MgCl2*6H2O}$ ($M_\mathrm{r}$ = 203), is dissolved in water to make 0.250 $\mathrm{dm^3}$ of solution. What is the concentration of chloride ions, in $\mathrm{mol\,dm^{-3}}$, in this solution? A. 0.0400 B. 0.0800 C.…