Paper 1 2017

Question 1

How many protons, neutrons and electrons are in P 3-

Answer 1

Protons 15
Neutrons 16
Electrons 18

Question 2

Explain why phosphorous (III) chloride molecule is pyramidal with a bond angle less than 109.5 (2)

Question 3

What is the polarity (non-polar or polar) of the P-Cl bond and overall polarity of the phosphorous (III) chloride molecule ?

Answer 3

P-Cl bond =
Overall molecule =

Question 4

Give the formulae and mass/charge ratio of the ions responsible for the molecular ion peaks of phosphorous (III) chloride (2)
Phosphorous isotope mass number = 31
Chlorine has isotopes of 35 and 37

Question 5

Explain in terms of oxidation numbers that magnesium nitrate decomposing is a redox reaction (3)
2Mg(NO3)2 -> 2MgO + 4NO2 + O2

Question 6

Explain why calcium nitrate requires a higher temperature than magnesium nitrate in terms of charge and size of the cations (3)

Question 7

Referring to any changes in oxidation number when these halides react with concentrated sulfuric acid to produce the products (in Image), explain which halide is the strongest reducing agent (KCl, KBr or KI) (3)

Answer 7

KI as the iodide ions reduce H2SO4 ( oxi number of +6) to SO2 (+4) to H2S (0)

KBr - the bromide ions reduce sulfur from +6 to +4

KCl

Question 8

Write the ionic equation and calculate the e cell value for the reaction between MnO4 - ions and Br- ions
Br2 (aq) +2e- (eqm arrows) 2Br- (aq) +1.09
MnO4- (aq) + 8H+ (aq) + 5e- (eqm arrows) Mn2+ (aq) + 4H2O (l)