Zadanie 3d

(i) x-axis labelled reaction progress / reaction pathway / reaction coordinate AND y-axis labelled «potential» energy / enthalpy ✔

curve with one maximum, with the products at a lower energy than the reactants «exothermic» ✔

labelled arrow or line showing E_a from the reactants up to the top of the curve ✔

(ii) a greater proportion of molecules has energy equal to or greater than E_a ✔

the rate of successful collisions per unit time rises / a larger fraction of collisions is successful ✔

(iii) «provides» an alternative reaction pathway / mechanism ✔

with a lower E_a

OR

a larger fraction of collisions reaches the lowered energy requirement ✔

(iv) SO₂: +4 AND SO₂Cl₂: +6 ✔

(v) $K_c = \dfrac{[\ce{SO2Cl2}]}{[\ce{SO2}][\ce{Cl2}]}$ ✔

(vi) shifts to the right / towards SO₂Cl₂ «products»

AND

fewer moles / molecules of gas on the right «one mole of gas, compared with two moles on the left» ✔

(i) "Reaction" or "time" alone is not enough for the x-axis label. A two-headed arrow for E_a is acceptable but an arrow pointing downward is not. Profiles that show an intermediate are also fine. (ii) "More collisions" on its own does not earn M2; it must be linked to collisions per unit time or to the chance that a collision succeeds. (iii) Accept a description of how the catalyst lowers E_a, such as reactants adsorbing on its surface and their bonds weakening, for M1. (iv) Signs written after the number (4+, 6+) are not accepted. (vi) [1] for both the direction of the shift (to the right / towards the product) and the reason; a shift to the right without the reason, or the reason without the direction, earns no mark.