CourseCourseConceptConceptDocsDocuments

CAIE A-Level Chemistry AS 12.1 Nitrogen and Sulfur Questions

Practise explaining nitrogen inertness, ammonia acid–base chemistry and the atmospheric reactions of nitrogen oxides.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • explain nitrogen’s low reactivity using its strong non-polar N≡N triple bond
  • use proton transfer to explain ammonia basicity, ammonium formation and ammonia displacement
  • connect NO and NO2 separately to catalytic converters, PAN formation and acid-rain chemistry

Covered syllabus points

12.1.1—Lack of reactivity of nitrogen, using triple12.1.2—And explain12.1.3—NOx sources and catalytic removal12.1.4—Atmospheric NOx and photochemical smog12.1.5—Role of NO and NO2 in the formation of acid

Question 1

[Maximum number: 1]

Compounds P, Q and R have all been found in the atmosphere of one of Saturn's moons.
P

Figure for Question 1 — CAIE A-Level Chemistry AS
Q

Q

R

R

The equation for the complete combustion of P,C4 N2(I)\mathbf{P}, \mathrm{C}_{4} \mathrm{~N}_{2}(\mathrm{I}), is shown.

C4 N2(I)+4O2( g)→4CO2( g)+N2( g)ΔH=−2036 kJ mol−1\mathrm{C}_{4} \mathrm{~N}_{2}(\mathrm{I})+4 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 4 \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{N}_{2}(\mathrm{~g}) \quad \Delta H=-2036 \mathrm{~kJ} \mathrm{~mol}^{-1}

One of the products of the complete combustion of P is nitrogen gas, N2( g)\mathrm{N}_{2}(\mathrm{~g}).

Explain the lack of reactivity of nitrogen.

Question 2

[Maximum number: 5]

Nitrogen and phosphorus are elements in Group 15 of the Periodic Table.

Question (a)

(a)

Nitrogen is found in inorganic compounds such as nitrogen oxides ( NOx\mathrm{NO}_{x} ), nitrates and nitric acid.

[ 4 ]

Question (i)

(i)

Identify one natural and one man-made occurrence of nitrogen oxides in the atmosphere.
natural
man-made

[ 2 ]

Question (ii)

(ii)

Write an equation to describe the role of NO2\mathrm{NO}_{2} in the direct formation of acid rain.

[ 1 ]

Question (iii)

(iii)

Peroxyacetyl nitrate, PAN, is a component of photochemical smog.

Describe how PAN forms from NO2\mathrm{NO}_{2}.

3 Nitrogen and phosphorus are elements in Group 15 of the Periodic Table.
(v) Describe what is seen when solid calcium nitrate is heated strongly.
(b) A common test for nitrates is the reaction with NaOH and Al . Equation 1 shows the reaction.

[ 1 ]

Question (b)

(b)

A common test for nitrates is the reaction with NaOH and Al . Equation 1 shows the reaction.

 equation 13NO3−+8Al+5OH−+18H2O→3NH3+8[Al(OH)4]−\text { equation } 1 \quad 3 \mathrm{NO}_{3}^{-}+8 \mathrm{Al}+5 \mathrm{OH}^{-}+18 \mathrm{H}_{2} \mathrm{O} \rightarrow 3 \mathrm{NH}_{3}+8\left[\mathrm{Al}(\mathrm{OH})_{4}\right]^{-}
[ 1 ]

Question (i)

(i)

NH3\mathrm{NH}_{3} is a basic gas.

Describe how NH3\mathrm{NH}_{3} is able to act as a base.

[ 1 ]
All question bank results loaded