Оксиды. 1 часть. 8 класс.

Summary

In this chemistry lesson, the teacher introduces oxides, inorganic compounds that consist of two elements, one of which is always oxygen. The lesson covers their nomenclature, including both old and international naming conventions, and explains how oxides are classified by aggregate state (solid, liquid, or gas) and by their chemical behavior (basic, acidic, or amphoteric). Key examples like CO₂, CaO, and Al₂O₃ illustrate different types of oxides. The lesson also delves into how amphoteric oxides, such as Al₂O₃ and ZnO, behave both as acids and bases, providing a comprehensive understanding of oxides in chemistry.

Takeaways

• 😀 Oxides are compounds made up of two elements, with oxygen always being one of them. Their general formula is X2O_Y.
• 😀 The naming of oxides can follow old nomenclature (e.g., 'carbon oxide (IV)') or international nomenclature (e.g., 'carbon dioxide').
• 😀 Oxides can be classified based on their state: solid (e.g., CaO, Al2O3), liquid (e.g., SO3), or gas (e.g., CO2, SO2).
• 😀 Non-salt-forming oxides, like CO, rarely participate in reactions that produce salts.
• 😀 Salt-forming oxides, such as CO2 and Al2O3, can react with other substances to create salts.
• 😀 Basic oxides are typically metals with a valence of one or two (e.g., CaO, Cu2O). They correspond to bases like Ca(OH)2.
• 😀 Acidic oxides have a valence greater than three and can react to form acids, such as CO2 forming H2CO3.
• 😀 Amphoteric oxides have dual properties and can act as both acidic and basic oxides, with examples like Al2O3 and ZnO.
• 😀 The classification of oxides by chemical nature is crucial for understanding their behavior in chemical reactions.
• 😀 A useful method for finding the corresponding acid for an acidic oxide involves adding water to the oxide and observing the result, as shown with CO2 leading to H2CO3.

Q & A

What is the definition of oxides?

Oxides are complex compounds made up of two elements, one of which is always oxygen. The general formula of oxides is XoY, where X represents an element and O represents oxygen.

Can you give an example of an oxide that we breathe out?

An example of an oxide we breathe out is carbon dioxide (CO2), which is a binary compound consisting of carbon and oxygen.

What is the old nomenclature for naming oxides?

In the old nomenclature, oxides were named by identifying the element first, followed by the word 'oxide'. For example, CO2 is called 'oxide of carbon', and its valency is written in parentheses as 'oxide of carbon(IV)'.

What is the international nomenclature for naming CO2?

According to the international nomenclature, CO2 is named 'carbon dioxide', where 'di-' indicates two oxygen atoms bound to carbon.

How do oxides differ in terms of their chemical behavior?

Oxides can be classified into three main types based on their chemical behavior: basic oxides, acidic oxides, and amphoteric oxides. Basic oxides correspond to bases, acidic oxides to acids, and amphoteric oxides can behave both as acids and bases depending on the circumstances.

What is an example of a basic oxide?

An example of a basic oxide is calcium oxide (CaO), which is formed by the reaction of calcium, a metal with a valency of 2, with oxygen.

What is an amphoteric oxide?

An amphoteric oxide is one that can react both as an acid and a base. An example is aluminum oxide (Al2O3), where aluminum has a valency of 3.

What are some examples of acidic oxides?

Examples of acidic oxides include carbon dioxide (CO2) and sulfur trioxide (SO3). These oxides form acidic solutions when they react with water, such as carbonic acid (H2CO3) and sulfuric acid (H2SO4).

What are the different states in which oxides can exist?

Oxides can exist in three different aggregate states: solid, liquid, and gas. For example, solid oxides include calcium oxide (CaO), liquid oxides include sulfur trioxide (SO3), and gas oxides include carbon dioxide (CO2).

How do you determine the acid or base that corresponds to an oxide?

To determine the acid or base that corresponds to an oxide, you can use a graphical rule where you add water to the oxide's formula. For instance, adding water to CO2 results in H2CO3 (carbonic acid), and adding water to SO3 gives H2SO4 (sulfuric acid).