Top Banner

of 14

Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript

Al Waha International School Group IV Worksheet Grade 12 Name: . 1 (a) Date:

The melting points of some oxides of Group IV elements are given below.

Describe the bonding in each oxide, and how it relates to its melting point. (i) CO2 ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (ii) SiO2 ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (iii) SnO2 ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ [3] (b) Writing balanced equations where appropriate, describe how the above three oxides differ in their reactions with

1

(i)

NaOH(aq), ................................................................................................................................ ................................................................................................................................ ................................................................................................................................

(ii)

HCl(aq). ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ [4]

(c)

The last oxide in Group IV, PbO2, reacts with concentrated hydrochloric acid liberating chlorine gas. Use the Data Booklet to calculate the Ecell and to write a balanced equation for this reaction. ......................................................................................................................................... .....................................................................................................................................[2] [Total: 9]

2

The elements of Group IV all form tetrachlorides with the general formula MCl4. (a) Draw a diagram of a molecule of SiCl4 stating bond angles.

[2]

2

(b)

Describe and explain how the volatilities of the Group IV chlorides vary down the group. ......................................................................................................................................... ......................................................................................................................................... ................................................................................................................................... [2]

(c)

The relative stabilities of the M 2+(aq) and M 4+(aq) ions also vary down Group IV. (i) Use the Data Booklet to illustrate this observation when M = Sn and M = Pb. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (ii) Use the Data Booklet to predict the products formed, and write equations for the reactions occurring, when an equimolar mixture of Sn2+(aq) and Sn4+(aq) is added to I2(aq),

................................................................................................................................ ................................................................................................................................ an equimolar mixture of Pb2+(aq) and Pb4+(aq) is added to SO2(aq).

................................................................................................................................ ................................................................................................................................ [4] (d) (i) The SnCl bond energy is +315 kJ mol1. Use this and other values from the Data Booklet to calculate H for the reaction MCl2(g) + Cl2(g) for the following cases. M = Si MCl4(g)

H = ........................................ kJ mol1 3

M = Sn

H = ........................................ kJ mol1 (ii) Do your results agree with the trend in relative stabilities of the +2 and +4 oxidation states in (c)? Explain your answer. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ [3] [Total: 11]

3

(a)

(i)

On the following grids, plot points showing the variation in the named property of the Group IV elements. Your points should show for each element, whether the melting point/electrical conductivity is high, medium or low. The point for silicon has already been plotted in each case.

(ii)

Suggest explanations of these trends in terms of the structure and bonding of the Group IV elements. melting point ................................................................................................................................ ................................................................................................................................

4

electrical conductivity ................................................................................................................................ ................................................................................................................................ [6] (b) Choose one reaction to illustrate each of the following statements. Write an equation for each of your chosen reactions, and describe what you would see as the reaction is carried out. (i) PbO is more stable than PbO2. ................................................................................................................................ ................................................................................................................................ (ii) CO is easily oxidised to CO2. ................................................................................................................................ ................................................................................................................................ (iii) Aqueous SnCl2 is a useful reducing agent. ................................................................................................................................ ................................................................................................................................ [4] [Total: 10]

4

(a)

(i)

By means of a clear, labelled diagram, describe the shape of the tin(IV) chloride molecule.

5

(ii)

Explain the shape of the tin(IV) chloride molecule in terms of its bonding. ................................................................................................................................ ................................................................................................................................ [2]

(b)

(i)

What would you expect to observe when tin(IV) chloride reacts with water? Suggest an explanation for your answer. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................

(ii)

Write an equation for the reaction between tin(IV) chloride and water. ................................................................................................................................ [3] [Total: 5]

5

(a)

Describe how the behaviour of the oxides of tin and lead in their +4 oxidation states differ on heating. ......................................................................................................................................... .................................................................................................................................... [1]

(b)

Explain the following by using data from the Data Booklet where appropriate, and writing equations for all reactions. (i) A sample of liquid PbCl4 is placed in a flask and the flask is gently warmed. A gas is evolved and a white solid is produced. When the gas is bubbled through KI(aq), purple fumes are produced. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................

6

(ii)

Repeating the same experiment using liquid SnCl4 instead of PbCl4 results in no evolution of gas, and no reaction with KI(aq). ................................................................................................................................ ................................................................................................................................ [4]

(c)

The molecule dichlorocarbene, CCl2, can be produced under certain conditions. It is highly unstable, reacting with water to produce carbon monoxide and a strongly acidic solution. (i) Suggest the electron arrangement in CCl2 and draw a dot-and-cross diagram showing this. Predict the shape of the molecule.

(ii)

Construct an equation for the reaction of CCl2 with water. ................................................................................................................................ [3] [Total: 8]

7

6

(a)

Fluorine is much more electronegative than both silicon and sulfur, but whereas the molecule of SF4 has an overall dipole, that of SiF4 has none. Suggest a reason for this difference. ......................................................................................................................................... .....................................................................................................................................[1]

(b)

Predict whether or not the following molecules will have an overall dipole. Place a tick in the appropriate column. compound BCl3 PCl3 CCl4 SF6 [2] molecule has an overall dipole molecule does not have an overall dipole

(c)

Boron and silicon are two elements adjacent to carbon in the periodic table. CCl4 does not react with water, whereas BCl3 and SiCl4 do react. (i) Suggest a reason for this difference in reactivity. ................................................................................................................................ ................................................................................................................................ (ii) Construct equations showing the reaction of these two chlorides with an excess of water. BCl3 ....................................................................................................................... SiCl4 ...................................................................................................................... [3]

8

(d)

When reacted with a small quantity of water, SiCl 4 produces an oxychloride X, SixClyOz. The mass spectrum of X shows peaks at mass numbers of 133, 149, 247, 263 and 396. (You should assume that the species responsible for all these peaks contain the 16O, the 35Cl and the 28Si isotopes only.) (i) Use these data to deduce the molecular formula of X.

molecular formula ......................................... (ii) Suggest the structures of the fragments responsible for the peaks at the following mass numbers. mass number 133 247 263 (iii) Hence suggest the displayed formula of X. structure

[5] [Total: 11] 9

Group IV WS Grade 12 Mark Scheme Jun 03, Q3 1.

10

Jun 08, Q3 2

11

Jun 11, P42, Q2 3

12

Nov 10, P43, Q8 [WS] 4

Jun 10, P41, Q3 5

13

Jun 10, P42, Q3 6

14