1 mark e how many neutrons are there in the nucleus

Info icon This preview shows pages 15–17. Sign up to view the full content.

View Full Document Right Arrow Icon
1 mark e. How many neutrons are there in the nucleus of the Sb isotope? 1 mark f. Two of the radioactive isotopes of antimony are Sb which decays by emission of a beta particle (an electron) and Sb which decays by positron emission (a positive electron). Give the symbol of the atoms produced from the decay process of each of the given radioactive isotopes. i. Sb ii. Sb 2 marks Total 13 marks
Image of page 15

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CHEM EXAM 2 16 Question 8 a. Cobalt is one of the three metals in the first transition series that is ferromagnetic (magnetic). Give the name or symbol of one of the other two ferromagnetic metals in the first transition series. 1 mark b. Cobalt can form the complex ion Co(NH 3 ) 6 3+ in the presence of ammonia. i. Sketch the structure for Co(NH 3 ) 6 3+ . ii. Name the type of bonding that exists • between Co 3+ ion and the NH 3 molecules • within the NH 3 molecule 1 + 2 = 3 marks c. Suggest a reason why NH 3 might bond more firmly to Co 3+ than to Co 2+ . 1 mark SECTION B – Question 8 – continued
Image of page 16
17 CHEM EXAM 2 d. Part of the electrochemical series is given below and should be used to answer the following questions. half reaction E o value in volt 1 Co(H 2 O) 6 3+ (aq) + e Co(H 2 O) 6 2+ (aq) 1.81 2 O 2(g) + 4H + (aq) + 4e 2H 2 O(l) 1.23 3 Co(NH 3 ) 6 3+ (aq) + e Co(NH 3 ) 6 2+ (aq) 0.10 4 2H + (aq) + 2e H 2 (g) 0.00 5 Co(H 2 O) 6 2+ (aq) + 2e Co(s) + 6H 2 O(l) –0.28 6 Co(NH 3 ) 6 2+ (aq) + 2e Co(s) + 6NH 3 (aq) –0.43 7 2H 2 O(l) + 2e H 2 (g) + 2OH (aq) –0.83 i. Select two of the above half reactions which together indicate that, in aqueous solution, NH 3 bonds to Co 3+ rather than to Co 2+ . ii. Explain, using the above data, why aqueous solutions containing Co(H 2 O) 6 3+ (aq) might be too unstable to be conveniently used in the laboratory. 2 marks Total 7 marks END OF QUESTION AND ANSWER BOOK
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

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