DHS Prelim P2_Qn

This document consists of 19 printed pages and 1 blank page.  DHS 2015 [Turn over Name: Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination 2015 Year 6 H2 CHEMISTRY 9647/02 Paper 2 Structured Questions 16 September 2015 2 hours Additional Materials: Data Booklet INSTRUCTIONS TO CANDIDATES 1 Write your name, index number and class on this cover page. 2 Answer all questions. 3 Write your answers in the spaces provided on the Question Paper. 4 The use of an approved scientific calculator is expected, where appropriate. 4 A Data Booklet is provided. 5 The number of marks is given in brackets [ ] at the end of each question or part question. Question No. 1 (P) 2 3 4 5 6 7 Total % Marks 12 15 15 6 9 10 5 [72]

2  DHS 2015 9647/02 [Turn over Answer all the questions in the spaces provided. 1 Planning (P) (a) Part (a) is on the rate of effusion of gas. If a container of gas has a tiny hole in it, the gas will gradually escape through the hole. This process is called effusion and the rate at which it occurs is called the rate of effusion. A student has carried out a series of preliminary experiments to investigate how the rate of effusion depends on the relative molecular mass, M r, of a gas. She found that the rate of effusion is halved when the Mr of a gas is doubled. (i) Using the apparatus shown below, plan a laboratory experiment to verify the student’s findings. The experiment will involve using different gases where their rate of effusion will be determined, bearing in mind that temperature will also affect the effusion rate of the gas. In addition to the standard apparatus present in a laboratory you are provided with the following:  access to samples of hydrogen, butane, oxygen, carbon dioxide and chlorine gases Your plan should include:  brief, but specific, details of the apparatus you would use;  how you ensure the syringe only contain the gas you are investigating;  how you would measure the effusion time;  how you produce reliable results;  steps taken to ensure other factors are controlled;  a table with appropriate headings to show the data you would record when carrying out your experiment and the values you would calculate in order to construct a graph to support or reject the statement. The headings must include the appropriate units. Retort stand clamp

3  DHS 2015 9647/02 [Turn over Table [You need not use all the columns in the following table.]

4  DHS 2015 9647/02 [Turn over (ii) Sketch a graph you would plot using your measured or calculated data obtained in (a)(i) and describe how you would use the graph to determine the effusion rate of nitrogen gas (Mr = 28.0). You may assume that the student’s findings is accurate. [8] (