1 / 7

Model Answer – AS 2.4 Melting points

Model Answer – AS 2.4 Melting points. Question: Discuss the relative melting points of sodium oxide (Na 2 O), silicon dioxide (SiO 2 ), and sulfur dioxide (SO 2 ). 1. Overview – types of bonding. Na 2 O (metal and non-metal) is an IONIC SOLID. SiO 2 (silica) is a COVALENT NETWORK SOLID.

sydnee
Download Presentation

Model Answer – AS 2.4 Melting points

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Model Answer – AS 2.4 Melting points • Question: Discuss the relative melting points of sodium oxide (Na2O), silicon dioxide (SiO2), and sulfur dioxide (SO2)

  2. 1. Overview – types of bonding • Na2O (metal and non-metal) is an IONIC SOLID • SiO2 (silica) is a COVALENT NETWORK SOLID • SO2 (non-metals) is a COVALENT MOLECULAR SOLID

  3. 2. Rank the melting points • Na2O → ionic solid → HIGH MPT • SiO2 → covalent network solid → HIGH MPT • SO2 → covalent molecular solid → LOW MPT • In general, network is the highest so SiO2> Na2O > SO2

  4. 3. Discuss each substance in terms of STRUCTURE, and relate the structure to the PROPERTY (in this case mpt, but could be solubility or conductivity)

  5. Na2O STRUCTURE • Sodium oxide is an ionic solid. It consists of positive and negative IONS in a 3D lattice structure. The ions are held together by STRONG ionic bonds. These bonds require a lot of energy to disrupt therefore sodium oxide has a HIGH MPT BONDING Related to PROPERTY

  6. SiO2 STRUCTURE • Silicon dioxide is a covalent network solid. It consists of silicon and oxygen ATOMS in an extended network, all atoms bonded by STRONG COVALENT BONDS. These bonds require a lot of energy to disrupt therefore silicon dioxide has a HIGH MPT BONDING Related to PROPERTY

  7. SO2 STRUCTURE • Sulfur dioxide is a covalent molecular solid. Although sulfur and oxygen ATOMS are covalently bonded making SO2 MOLECULES, the MOLECULES are bonded to other molecules by WEAK INTERMOLECULAR FORCES. These weak forces require little energy to disrupt therefore sulfur dioxide has a LOW MPT BONDING Related to PROPERTY

More Related