The properties of oxides
5 marks · HardThis question is about the nature of oxides.
Complete the table by identifying whether each oxide is acidic, basic or neutral.
| Oxide | Type (acidic, basic or neutral) |
|---|---|
| Sodium oxide | |
| Carbon dioxide |
Explain your answers for both oxides, referring to the type of element each oxide is formed from.
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(a) Sodium oxide: basic; Carbon dioxide: acidic · must show Sodium oxide is basic, Carbon dioxide is acidic
(b) Sodium oxide is basic because it is a metal oxide, formed from the metal sodium. Carbon dioxide is acidic because it is a non-metal oxide, formed from the non-metal carbon. · must show Links sodium oxide to metal oxide/basic, Links carbon dioxide to non-metal oxide/acidic, Mentions sodium is a metal and carbon is a non-metal OR clear reference to the element type
Common mistakes: Sodium oxide is acidic; Carbon dioxide is basic
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Marking points
B1 (a) · 1 mark · Sodium oxide identified as basic
B2 (a) · 1 mark · Carbon dioxide identified as acidic
B3 (b) · 1 mark · Explains sodium oxide is basic as it is a metal oxide or formed from a metal
B4 (b) · 1 mark · Explains carbon dioxide is acidic as it is a non-metal oxide or formed from a non-metal
B5 (b) · 1 mark · Refers to the type of element (sodium is a metal, carbon is a non-metal), or clearly links to element type for both
Worked solution
| Oxide | Type (acidic, basic or neutral) |
|---|---|
| Sodium oxide | Basic |
| Carbon dioxide | Acidic |
Sodium oxide is basic because it is an oxide of a metal (sodium). Metal oxides are usually basic. Carbon dioxide is acidic because it is formed from a non-metal (carbon). Non-metal oxides are usually acidic.