Chemistry HL Paper 1B, November 2025, TZ3

Titanium is not included in the graph. Use sections 9 and 10 of the data booklet to find its atomic radius and first ionization energy, and annotate the graph with a cross (X) at the position of the data point for titanium.

Suggest what causes the two quantities in the graph to be related in this way.

The data show that the first ionization energy and the atomic radius are related. (i) State what kind of relationship links the two variables. (ii) Compare and contrast the trends observed for the three groups.

(i) Suggest one hazard to health or safety in Student A's procedure. (ii) Student A plotted the highest temperature of each mixture against the volume of nitric acid. With a ruler, draw two straight lines of best fit: one following the rising set of points and…

Student B pipetted 30.00 $\mathrm{cm^3}$ of the potassium hydroxide solution into a 150 $\mathrm{cm^3}$ glass beaker and added the nitric acid from a burette in portions of 4.00 $\mathrm{cm^3}$, recording the steady temperature after each addition. Volume of…

Describe the steps the student would follow to recrystallize the crude benzoic acid.

State the most important property that water must have, with respect to benzoic acid, for it to be a suitable solvent for this recrystallization.

Outline how each of the two by-products is removed from the benzoic acid during the recrystallization. By-product that is almost insoluble in hot water: ... By-product that is much more soluble than benzoic acid: ...

The volume of hot water used to dissolve the crude solid must be chosen carefully. Deduce the effect on the yield or on the purity of the recrystallized benzoic acid of using too much water and of using too little water. Too much water: ... Too little water:…

Chlorinated solvents such as tetrachloromethane, $\ce{CCl4}$, and 1,1,1-trichloroethane, $\ce{CH3CCl3}$, were once common in laboratories, but their production is now restricted by an international agreement. Besides climate change, state the specific…

Describe the setup that would connect the $\ce{Sn^4+}/\ce{Sn^2+}$ half-cell to a second half-cell for comparing the two electrode potentials.

The electrode potential, $E$, of the $\ce{Sn^4+}/\ce{Sn^2+}$ half-cell is not fixed: it depends on the concentrations of the two tin ions, as given by the equation: $E = 0.15 + \dfrac{RT}{2F}\ln\dfrac{[\ce{Sn^4+}]}{[\ce{Sn^2+}]}$ Determine the electrode…