OCR A AS Specimen Paper 2 Q7 (with explained solutions) |

Skip to content

OCR A AS Specimen Paper 2 Q7

Answers available below

7 An alcohol A contains carbon, hydrogen and oxygen only. The alcohol is a liquid at room temperature and pressure but can easily be vaporised. 1.15 g of A produces 761 cm3 of gas when vaporised, measured at 100 kPa and 366 K. Determine the molar mass of compound A and draw a possible structure for A. Show all your working. molar mass =g mol1 18 Structure of A Specimen END OF QUESTION PAPER [5]OCR 2014 H032/02<br />

Show answer

RT (cid:57) 8.314 (cid:117) 366 FIRST CHECK THE ANSWER ON THE ANSWER LINE IF answer = 46.0 (g mol1) award 4 marks for calculation Rearranging ideal gas equation to make n subject n = pV Substituting all values taking into account conversion to Pa and m3 n = (100 (cid:117) 103) (cid:117) (761 (cid:117) 106) n = 0.0250 mol (cid:57) Calculation of M M = m Identification of A (cid:57) Specimen If there is an alternative answer, check to see if there is any ECF credit possible using working below 1st mark may be implicit in direct substitution of correct values into rearranged equation. ALLOW any unambiguous structure ALLOW C2H5OH DO NOT ALLOW C2H6O n = 1.15 0.0250 = 46.0 (g mol1) (cid:57) (cid:57) H032/02 Question 7 Mark Scheme June 20XX Answer Marks Guidance Total 18 P M T<br />

Question 1 2 3 4 5 6 7 16 17 18 19 20 21

About us | Need Help? | Feedback

Proudly powered by WordPress | Theme: Sydney by aThemes.