A-level CHEMISTRY Paper 2 Organic and Physical Chemistry

A-level CHEMISTRY Paper 2 Organic and Physical Chemistry Monday 19 June 2023 Afternoon Time allowed: 2 hours Materials For this paper you must have: • the Periodic Table/Data Booklet, provided as an insert (enclosed) • a ruler with millimetre measurements • a scientific calculator, which you are expected to use where appropriate. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • All working must be shown. • Do all rough work in this book. Cross through any work you do not want to be marked. Information • The marks for questions are shown in brackets. • The maximum mark for this paper is 105. Answer all questions in the spaces provided. box This question is about rates of reaction. Figure 1 shows apparatus used to measure the rate of reaction when an acid reacts with an excess of solid sodium hydrogencarbonate, NaHCO3 When different monoprotic organic acids are used, the rates at which gas escapes can be used to compare the strengths of the acids. A timer is started when the NaHCO3 is added to the acid and the mass of CO2 gas lost is recorded at regular intervals. (It is assumed that any change in mass is due to the loss of CO2) Figure 1 . Suggest a reason why using a conical flask instead of a beaker would give more accurate results in this experiment. [1 mark] box 0 1 . 2 Use Figure 2 to calculate the rate of reaction at 2 minutes. Deduce the units of your calculated rate. [3 marks] Rate Units