(i) What property does Magnesium Oxide have that makes it useful to create heat-resistant bricks to line furnaces? (ii) Explain why H2S exists as a gas and H2O exists as a liquid (at r.t.p).

 (i)  Magnesium oxide is an ionic compound meaning the elements reside in a lattice held together by very strong electrostatic forces of attraction between their oppositely charged ions. Since bonds are broken by the input of energy (an endothermic process) MgO has a very high melting point making it an appropriate material to use. (ii)  The reason H2O exists as a liquid is due to Oxygen being more electronegative than Sulphur which allows it to polarise the oxygen-hydrogen bond. The partially positive Hydrogens are then attracted to the ‘negative’ Oxygens of other water molecules resulting in an additional set of intermolecular attractive forces known as hydrogen bonding. Since Sulphur cannot polarise Hydrogen very much there is no Hydrogen bonding. You can think of it as water molecules not having enough energy to break off from each other to become a gas whereas H2S molecules don’t have the same type of ‘hold’ on each other. This ‘hold’ between molecules is determined by intermolecular forces. The more you have, the tighter the hold.

SN
Answered by Shahaab N. Chemistry tutor

16140 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

The equation for the reaction between ammonia and oxygen is shown. 4NH3(g) + 5O2(g) ⇌ 4NO(g) + 6H2O(g) . Calculate the entropy change of the reaction, using data from the table below.


State and explain the general trend in the first ionisation energies of the Period 2 elements Lithium to Fluorine.


Briefly describe the nature of three types of intramolecular bonding and two types of intermolecular bonding (drawings encouraged)


What is Gibbs Free Energy?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences