CIE iGCSE Co-Ordinated Science C2.4 Ions and ionic bonds Exam Style Questions Paper 4
Question
(a) Particles can be atoms, ions or molecules. Particles either form pure substances or mixtures.
Draw one line from each word to the correct definition. One has been done for you.
(b) Particles can diffuse at different rates.
Fig. 5.1 shows an experiment to investigate diffusion of gas particles.
Ammonia gas, NH$_{3}$, and hydrogen chloride gas, HCl, diffuse along the tube.
When the gases meet, they react to form a white cloud of ammonium chloride.
(i) The ammonium chloride forms at the end of the tube furthest from the ammonia.
Explain why, in terms of the movement of molecules.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(ii) Calculate the volume occupied by 5.1g of ammonia gas.
The molar gas volume at room temperature and pressure is 24dm$^{3}$.
Show your working.
volume of ammonia gas = ……………………….. dm$^{3}$
▶️Answer/Explanation
Ans: 5(a)
one mark for each additional correct line ;;;;
5(b)(i) molecular mass of ammonia is less (than hydrogen chloride)/ORA ;
ammonia particles diffuse / move faster (than hydrogen chloride particles/molecules)/ORA ;
5(b)(ii) M$_{r}$ of NH$_{3}$ = 17 ;
moles of NH$_{3}$ = 5.1 $\div $ 17 = 0.3
volume of NH$_{3}$ = 0.3 × 24 = 7.2(0) dm$^{3}$ ;