A full 40-mark Paper 032 style practice paper with three questions — acid–base titration, rate of reaction, and an investigation of conductivity — with marks tagged for experimental skills and use of knowledge.
4 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Forty marks, three practical questions. Work through this paper in writing, as you would in the examination hall, then self-mark it against the scheme.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
3 questions; 40 marks: Q1 14, Q2 13, Q3 13.
Experimental Skills [XS] 30; Use of Knowledge [UK] 10.
n = C × V; ratio; mean of concordant titres.
Gas syringe; volume against time; rate is the gradient.
Strong electrolyte: more ions, brighter bulb.
Quantity and unit in every heading.
2 h 10 min: about 3 minutes per mark.
Tick each point you earned and note missed skills.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (40 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [14 marks]
A student titrates 25.0 cm³ portions of sodium hydroxide solution with 0.100 mol/dm³ hydrochloric acid, using methyl orange. The rough titre is 25.20 cm³. The accurate titres are 24.90, 24.50 and 24.50 cm³.
(a) (a) Describe, with a labelled diagram, how the student should carry out the titration. [5]
(b) (b) Draw a table with suitable headings for the titration results. [3]
(c) (c) State which titres should be used for the mean titre and calculate it. [2]
(d) (d) Calculate the moles of hydrochloric acid used and state the moles of sodium hydroxide, given that NaOH + HCl → NaCl + H₂O. [2]
(e) (e) Calculate the concentration of the sodium hydroxide solution in mol/dm³. [2]
Question 2 [13 marks]
A student reacts magnesium ribbon with excess 1.0 mol/dm³ hydrochloric acid and collects the hydrogen in a gas syringe. The volume of gas is 0, 24, 40, 50, 56, 59 and 60 cm³ at times 0, 30, 60, 90, 120, 150 and 180 s.
(a) (a) Describe how the student collects and measures the gas. [5]
(b) (b) Draw a table with suitable headings for the results. [2]
(c) (c) State how the results should be plotted and what the graph will look like. [3]
(d) (d) State when the rate is fastest and give a reason. [1]
(e) (e) Explain why the total volume of gas is 60 cm³. [1]
(f) (f) State the effect of using warmer acid on the rate and the final volume. [1]
Question 3 [13 marks]
A student wants to compare the electrical conductivity of 0.1 mol/dm³ hydrochloric acid and 0.1 mol/dm³ ethanoic acid.
(a) (a) Write a hypothesis and an aim for the investigation. [2]
(b) (b) List the apparatus and materials needed. [2]
(c) (c) Describe the method. [3]
(d) (d) Identify the manipulated variable, the responding variable and the controlled variables. [3]
(e) (e) Predict the result and explain it. [2]
(f) (f) State why carbon electrodes are used. [1]
Everything in this lesson is based on these parts of the CXC syllabus and papers.