Edexcel Jun 2014 Paper 2 Q20 (with explained solutions) |

Skip to content

Edexcel Jun 2014 Paper 2 Q20

Answers available below

Show answer

Section B Question Number Acceptable Answers In (a) any units given must be correct. Penalise incorrect units once only. Ignore SF except 1 SF in (i), (iii) and (iv). Penalise once only Volume Added/cm3 25(.00) 24.6(0) 24.5(0) 20 (a)(i) 24.55 (cm3) Reject Mark 24.70 24.60 Reject Mark Reject Mark 0.0613 0.06 Reject Mark 6CH0201 1406 Allow 24.6 (cm3) Question Number 20 (a)(ii) NaOH + HClNaCl + H2O Acceptable Answers Ignore state symbols even if incorrect Acceptable Answers Number of moles of NaOH = (24.55 x 2.5) = 6.1375 x 10-2 = 0.061375(mol) 1000 OR 6.14 x 10-2 = 0.0614 OR 6.1 x 10-2 = 0.061 Allow TE from 20(a)(i) Acceptable Answers 6.1375 x 10-2 /0.061375/ 6.14 x 10-2 / 0.0614/0.061(mol) Allow TE = answer to (a)(iii) Question Number 20 (a)(iii) Question Number 20 (a)(iv)<br />
Acceptable Answers Question Number 20 (a)(v) Reject Mark Multiply by 4 and by 36.5 (1) Using 6.1375 x 10-2 gives 8.96075 = 8.96 (g) OR Using 6.14 x 10-2 gives 8.9644 = 8.96(g) OR Using 6.1 x 10-2 gives 8.906 = 8.91(g) Answer to 3 SF (1) Correct answer without working score (2) Allow TE from (a)(iv) ALLOW one mark for correct answer to 3SF where the multiplication by 4 has been omitted, e.g. (6.1375 x 10-2 x 36.5 = 2.2401875 =) 2.24(g) (1) Question Number 20 (a)(vi) The statement is valid as 8.96 ~9/very close Acceptable Answers Allow appropriate comment from answer to (a)(v) e.g 2.24 is not valid because it is too far away from 9g. Reject Mark Just not valid / valid Question Number 20 a(vii) Acceptable Answers Reject (Too) corrosive Damages eyes/burns (skin)/caustic Ignore Dangerous/Strong/Too concentrated Just Harmful/Irritant/Toxic/Hazardous Acid Mark 6CH0201 1406<br />
Acceptable Answers Question Number 20 (b) Reject Mark Allow all dots or all crosses ALLOW ionic dot and cross Or dative covalent bond from chlorine Acceptable Answers Reject HCl + HOClH2O + Cl2 (1) Ignore state symbols even if incorrect Chlorine is toxic/poisonous (1) Allow fumes are toxic Ignore references to smell or colour Just Harmful/ irritant/dangerous/ hazardous Mark 6CH0201 1406 Question Number 20 (c)<br />
Question Number 20 (d)(i) Acceptable Answers -1 +1 (2NaOH + Cl2NaCl + NaClO + H2O) All oxidation numbers correct (1) Type: Disproportionation (1) Allow phonetic spellings Allow redox and disproportionation Second mark consequential on the first except if (i) all the oxidation numbers are zero (ii) the plus sign is missing, (iii) the first two oxidation numbers are correct and the third one is positive If all the elemental oxidation numbers are given correctly then both marks are available Question Number 20 (d)(ii) Heat/increase temperature Acceptable Answers ALLOW (more) concentrated NaOH Mark Reject Just redox Reject Just warm / excess NaOH Acid Reject Mark Mark Question Number 20 (d)(iii) 3Cl2 + 6NaOH5NaCl + NaClO3 + 3H2O Acceptable Answers OR3Cl2 + 6OH5Cl + ClO3 + 3H2O(1) Formula of NaClO3 / ClO3 Rest of equation correct (1) Ignore state symbols even if incorrect TOTAL FOR Q20 = 16 MARKS 6CH0201 1406<br />

Question 17 18 19 20 21 22

About us | Need Help? | Feedback

Proudly powered by WordPress | Theme: Sydney by aThemes.