"Cherish and Protect Metal Resources" Metal PPT Courseware 4

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"Cherish and Protect Metal Resources" Metal PPT Courseware 4

1. Consumption of metal resources

Information 1: Human beings require a large amount of metal mineral resources from nature every year to extract hundreds of millions of tons of metals. Metal minerals have limited reserves and are not renewable. Based on the proven reserves of some minerals and the current consumption rate of these metals, some people estimate that the number of years some minerals can be mined is as shown in the figure below (excluding newly proven mineral reserves in the future and metal reserves in some countries) and metal recycling, etc.).

Information 2: According to relevant reports, the metal equipment and materials scrapped due to corrosion every year in the world are equivalent to 20% to 40% of the annual output.

1. Research on conditions for iron rusting

We now have clean and rust-free iron nails, test tubes, boiled and rapidly cooled distilled water, vegetable oil, dilute hydrochloric acid, cotton and desiccant calcium chloride. Design experiments to demonstrate the conditions under which iron products corrode.

Design experiments to demonstrate the conditions under which iron products corrode.

discuss:

1. What are the main factors causing steel corrosion?

2. What substances does iron mainly react with to cause rust, and what is produced?

The composition of rust is very complex, mainly iron oxide Fe2O3. The loose and porous structure of rust absorbs moisture and accelerates the rust of iron products.

2. Rust of other metals

In addition to iron, many metals (such as copper, aluminum, etc.) will also react with substances in the environment (such as air, water)

Discussion: Aluminum and zinc are commonly used metals in daily life. For example, aluminum alloy doors, windows, and cans all contain aluminum metal; the zinc sheet used as the negative electrode in dry batteries and the coating on the surface of iron wire all contain zinc. So why don't these metals "rust"?

After analysis and research, metals such as aluminum and zinc are easily oxidized in the air. A dense oxide film is formed to prevent further intrusion of water and oxygen to protect the metal.

2. Metal protection

1. How to prevent iron from rusting

(1). Add paint, grease or enamel

(2). Plated with other metals, such as tin or chromium, etc.

Summary: Methods to prevent metal corrosion

(1) Isolate air or oxygen (2) Isolate water

Change the internal structure of metal

Made into alloys such as stainless steel

form a protective layer

Painting, oiling, and firing enamel (physical methods)

Electroplating a layer of corrosion-resistant metal (chrome plating, zinc, tin), forming a dense oxide film on the surface through chemical reaction, etc.

Improve the corrosive environment, etc.

Keep iron surfaces dry and clean

2. Metal resource protection

In addition to taking measures to prevent metal corrosion, what other ways can be used to protect metal resources?

What’s the point of recycling scrap metal?

Can save metal resources

Since metal smelting requires high temperatures, recycling and reusing scrap metal can save energy and reduce costs.

Can reduce metal pollution to the environment

In addition to recycling and utilizing scrap metal, are there any other ways to protect metal resources?

Protect metal resources

From the aspect of resource collection and exploitation

(1) Recycling and utilizing scrap metal

(2) Reasonable mining of minerals

(3) Looking for metal substitutes

From the perspective of protecting metal materials and products

Prevent metal corrosion

I will do it

1. Answer through experiments. In which of the following situations do iron nails tend to rust?

(1) In dry air

(2) In humid air

(3) Partially immersed in salt water

(4) Soak in vegetable oil

2. The following methods can prevent iron products from rusting ( )

A. If the bicycle is dirty, rinse it with clean water.

B. Use waste acid to flush iron sewage pipes

C. Apply a layer of paint to the iron basketball stand

D. After cutting the pickles, wash and dry the kitchen knife as soon as possible

3. With the improvement of people's quality of life, the use of various batteries has increased significantly, and the issue of centralized treatment of waste batteries has been put on the agenda. The primary reason is ( )

A Recycling of metal materials from battery casings

B Prevent heavy metals such as mercury, cadmium, and lead in batteries from contaminating soil and water sources

C Reduce the corrosion of liquid leaking from the battery to other items

D Recycling of graphite electrodes in batteries

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For more information about the PPT courseware "Metal Cherishing and Protecting Metal Resources", please click the Metal ppt Cherishing and Protecting Metal Resources ppt tab.

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Update Time: 2024-10-19

This template belongs to Chemistry courseware Cantonese Education Edition Ninth Grade Chemistry Volume 2 industry PPT template

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