3p 1 1dii m1 in s the electron is removed from the 2

This preview shows page 4 - 8 out of 9 pages.

3p 1 1(d)(ii) M1 (in S, the electron is removed from the) 2 electrons in (3) p orbital OR a pair of electrons in (3) p (orbital / sub-shell) M2 (paired electrons) repel 2
Image of page 4
9701/23 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 5 of 9 Question Answer Marks 2(a)(i) held in regular / uniform arrangement 1 2(a)(ii) M1 covalent (bonds) AND (temporary) induced dipoles M2 (temporary) induced dipoles 2 2(b)(i) 2 1 2(b)(ii) iodine (atom / s) donates a pair of electrons (to the A l -I covalent bond / s). 1 2(c)(i) 2H 2 SO 4 + 14H I 7 I 2 + 8H 2 O + H 2 S + S M1 correct species M2 correctly balanced equation 2 2(c)(ii) explain with ref to ox no’s why the reaction in (c)(i) is a redox reaction M1 I (oxidation number increases) from –1 to 0 = oxidation / reducing agent M2 S (oxidation number decreases) from (+) 6 to 0 OR –2 = reduction / oxidising agent 2
Image of page 5
9701/23 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 6 of 9 Question Answer Marks 3(a) white light / flame AND (produces a) white / grey solid / ash / powder / smoke 1 3(b)(i) MgO + 2HC l MgC l 2 + H 2 O 1 3(b)(ii) neutralisation 1 3(c) M1 giant (structure / lattice) M2 (so) lots of energy needed to break the bonds OR strong bonds 2 3(d)(i) MgCO 3 (s) MgO(s) + CO 2 (g) 1 3(d)(ii) (thermal) decomposition 1
Image of page 6
9701/23 Cambridge International AS/A Level – Mark Scheme PUBLISHED May/June 2019 © UCLES 2019 Page 7 of 9 Question Answer Marks 4(a) M1 sulfur impurities OR sulfur in fossil fuels M2 converted into SO 2 by combustion / burning sulfur OR heat sulfur with oxygen (from the air) 2 4(b)(i) M1 1 mol SO 2 1 mol H 2 SO 4 64.1 g / tonne 98.1 g / tonne M2 SO 2 98.1 / 64.1 1590 = 2433.369735 tonnes 2 4(b)(ii) high (enough) temperature / (a lot of) heat (energy) is produced AND to break (strong) triple bond in N 2 / break N N AND nitrogen (and oxygen) from the air / atmosphere react Award two marks for three correct points Award one mark for two correct points 2 4(b)(iii) lightning 1 4(b)(iv) M1 nitrogen dioxide increases the rate OR lowers the activation energy M2 (NO 2 ) is regenerated by reaction of NO with O 2 (in the air) OR NO (formed) reacts with O 2 (in air) to (re)form NO 2 2
Image of page 7
Image of page 8

You've reached the end of your free preview.

Want to read all 9 pages?

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes
A+ icon
Ask Expert Tutors