4.3 Intermolecular Forces & Metallic Bonding

C₂H₆, C₄H₁₀ and C₃H₈ are alkanes.

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Pentane can exist as isomers, including pentane, CH₃CH₂CH₂CH₂CH₃ and 2,2-dimethylpropane, CH₃C(CH₃)₂CH₃.

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There are two isomers possible with the molecular formula C₂H₆O.

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Explain why transition metals, such as iron, alloy best with other transition metals, such as nickel.

State the name of the most common type of iron alloy and the element it is alloyed with.

Describe and explain the trend in the melting points of all the Group 1 metals as you descend the group.

Use page 7 of the Data book.

Describe and explain the trend in melting points across the Period 3 metals of sodium, magnesium and aluminium.

Use page 7 of the Data book.

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Based on the type of intermolecular force present, explain why butan-1-ol has a higher boiling point than butanal.

Ethane, C₂H₆, and disilane, Si₂H₆, are both hydrides of Group 4 elements with similar structures but different chemical properties.

Explain why disilane has a higher boiling point than ethane.

Put the following molecules in order of increasing boiling point and explain your choice:

Based on the type of intermolecular force present, explain the difference in solubility in water between ethane and ethanol.

The elements sodium, aluminium, silicon, phosphorus and sulfur are in period 3 of the periodic table.

Describe and explain the general trend in melting points of the metals in period 3.

Identify, with reasoning, which of the period 3 metals has the highest melting point.

Explain, by reference to the intermolecular forces, why sulfur has a higher melting point than phosphorus.

Although the molar masses of ICl and Br₂ are very similar, the boiling point of ICl is 97.4 °C and that of Br₂ is 58.8 °C.

Explain the difference in these boiling points in terms of the intermolecular forces present in each liquid.

The melting points of some Group 1 elements are listed in Table 1.

Table 1

Predict, with a reason, the melting point of Rb.

Explain why ammonia, NH₃, is a gas at room temperature. 

Phosphine (IUPAC name phosphane) is a hydride of phosphorus, with the formula PH₃. Phosphine has a much greater molar mass than ammonia.

Explain why phosphine has a significantly lower boiling point than ammonia.

Identify the type of interaction that must be overcome when liquid hydrazine, N₂H₄, vaporizes. Suggest, with a reason, whether hydrazine has a lower or higher boiling point than diimide, N₂H₂.

Copper is a transition metal. Describe the bonding in metals.

Aluminium and copper can be used to make the alloy duralumin.

Explain why an aluminium-copper alloy is harder than pure aluminium.

This question is about the chlorides of copper and aluminium.

Both copper and benzene have delocalised electrons. Explain why both structures have delocalised electrons, copper conducts electricity, but benzene does not.