EduNinja
[Maximum number: 2]

Species such as NH4+,CO32−\mathrm{NH}_{4}{ }^{+}, \mathrm{CO}_{3}{ }^{2-} and PO43−\mathrm{PO}_{4}{ }^{3-} are examples of molecular ions.

(a)

NH4+\mathrm{NH}_{4}{ }^{+}is a Brønsted-Lowry acid.

[ 2 ]
(i)

The nitrogen atom in NH4+\mathrm{NH}_{4}{ }^{+}is sp3\mathrm{sp}^{3} hybridised. sp3\mathrm{sp}^{3} orbitals form from the mixing of one 2 s and three 2 p orbitals.

Sketch the shapes of a 2 s and a 2px2 p_{x} orbital on the axes in Fig. 1.1.

Fig. 1.1

Fig. 1.1

[ 2 ]
[Maximum number: 1]

When considering one molecule of ethene, which row describes both the hybridisation of the atomic orbitals in the carbon atoms and the overall bonding?

hybridisation

bonding

sp2\mathrm{sp}^{2}

4σ4 \sigma bonds 1π1 \pi bond

sp2\mathrm{sp}^{2}

5σ5 \sigma bonds 1π1 \pi bond

sp3\mathrm{sp}^{3}

4σ4 \sigma bonds 1π1 \pi bond

sp3\mathrm{sp}^{3}

5σ5 \sigma bonds 1π1 \pi bond

[Maximum number: 1]

Which molecule contains a nitrogen atom with sp hybridised orbitals?

A

CH3CH2NH2\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2}

B

HNO3\mathrm{HNO}_{3}

C

HCN

D

NH3\mathrm{NH}_{3}

[Maximum number: 1]

The molecular formula C3H6\mathrm{C}_{3} \mathrm{H}_{6} represents the compounds propene and cyclopropane.

propene

propene

cyclopropane

cyclopropane

(a)

What is the H-C-H bond angle at the terminal =CH2=\mathrm{CH}_{2} group in propene?

[ 1 ]
[Maximum number: 1]

The formula CH3\mathrm{CH}_{3} can represent an anion, a cation or a free radical. Species with the molecular formula CH3\mathrm{CH}_{3} can act as an electrophile, a free radical or a nucleophile depending on the number of outer shell electrons on the central carbon atom.

How many outer shell electrons must be present for CH3\mathrm{CH}_{3} to act in these different ways?

CH3\mathrm{CH}_{3} as an

electrophile

CH3\mathrm{CH}_{3} as a

free radical

CH3\mathrm{CH}_{3} as a

nucleophile

6

7

8

6

8

7

7

6

8

8

7

6

[Maximum number: 1]

The diagram shows a molecule that has σ\sigma bonds and π\pi bonds.

Question image

How many σ\sigma bonds are present in this molecule?

A

15

B

17

C

18

D

21

[Maximum number: 1]

Poly(propene) is an addition polymer.
What are the C-C-C bond angles along its polymer chain?

A

They are all 109∘109^{\circ}.

B

Half of them are 109∘109^{\circ} and half are 120∘120^{\circ}.

C

Half of them are 90∘90^{\circ} and half are 180∘180^{\circ}.

D

They are all 120∘120^{\circ}.

(a)

Hydrogen cyanide, HCN , is a weak acid in aqueous solution.

HCN(aq)⇌H+(aq)+CN−(aq)Ka=6.2×10−10moldm−3\mathrm{HCN}(\mathrm{aq}) \rightleftharpoons \mathrm{H}^{+}(\mathrm{aq})+\mathrm{CN}^{-}(\mathrm{aq}) \quad K_{\mathrm{a}}=6.2 \times 10^{-10} \mathrm{moldm}^{-3}
[ 2 ]
(i)

State the hybridisation of the carbon and nitrogen atoms in hydrogen cyanide, and give the H-C-N bond angle.
hybridisation of C
hybridisation of N
H-C-N bond angle

[ 2 ]
[Maximum number: 1]

High-energy radiation in the stratosphere produces free-radicals from chlorofluoroalkanes, commonly known as CFCs.

Which free-radical is most likely to result from the irradiation of CHFClCF2Cl\mathrm{CHFClCF}_{2} \mathrm{Cl} ?

A

CHFClĊFCl

B

C˙HClCF2Cl\dot{\mathrm{C}} \mathrm{HClCF}_{2} \mathrm{Cl}

C

C˙HFCF2Cl\dot{\mathrm{C}} \mathrm{HFCF}_{2} \mathrm{Cl}

D

C˙FClCF2Cl\dot{\mathrm{C}} \mathrm{FClCF}_{2} \mathrm{Cl}

[Maximum number: 1]

How many σ\sigma and π\pi bonds are in the molecule HCCCH2CH2CHC(CH3)2\mathrm{HCCCH}_{2} \mathrm{CH}_{2} \mathrm{CHC}\left(\mathrm{CH}_{3}\right)_{2} ?

A

17σ3π17 \sigma 3 \pi

B

17σ5π17 \sigma 5 \pi

C

18σ4π18 \sigma 4 \pi

D

19σ3π19 \sigma 3 \pi

0