"Purification of Water" Water in Nature PPT Courseware 3

Description

"Purification of Water" Water in Nature PPT Courseware 3

teaching objectives

Knowledge and skills

Understand the difference between pure water and natural water, know common water purification methods such as precipitation, adsorption, and filtration, and initially learn filtration operations.

Process and Method

Able to proactively communicate and discuss with others during filtering operations, and clearly express one's views.

Emotional attitude values

Through experimental exploration, you can feel the positive significance of chemistry to life and society, and enhance your interest in learning chemistry.

Key points and difficulties in teaching

Key points: The difference between pure water and natural water, methods of purifying water.

Difficulty: How to operate filtering.

1. Pure water and natural water

1. Pure water

It is a colorless, odorless, clear and transparent liquid. It is a pure substance (chemical formula: H2O)

2. Natural water

River water, lake water, well water, sea water, etc. in nature are often turbid because they contain many soluble and insoluble impurities. Belongs to a mixture

filter

Filtration is a method of separating solids that are insoluble in liquids from liquids. It is suitable for separating solid-liquid mixtures. This method is often used to remove insoluble impurities from water.

Filtering in life:

1. What filtering operations have you used in your life?

2. How to use the equipment in the laboratory to perform filtration operations?

Hands-on experiments

Ask each group to spend 5 minutes filtering the clean water from the turbid water:

The following problems were solved in the experiment:

1. How to use glass rod to drain?

2. Where does the glass rod rest?

3. Where should the lower end of the funnel be placed during filtration?

think:

1. The filter paper must be tightly attached to the funnel without leaving any air bubbles (why?)

2. The edge of the filter paper is lower than the edge of the funnel (why?)

Instruments required for filtration experiments:

Filter paper, funnel, glass rod, beaker, iron stand (with iron ring)

Operation precautions:

One stick: The filter paper is close to the funnel wall and no air bubbles can be left.

Second low:

1. The edge of the filter paper in the funnel is lower than the edge of the funnel mouth.

2. The liquid level in the funnel is lower than the edge of the filter paper

Three things to rely on:

1. When pouring liquid, the beaker should be close to the glass rod.

2. The glass rod should be close to the three layers of filter paper.

3. The lower end of the funnel is close to the inner wall of the beaker

The purification effect of activated carbon in water

Activated carbon has a porous structure with a total surface area of ​​500 to 1000m2·g-1. It has strong adsorption ability. The main performance of purification in water is as follows:

Deodorization - remove odor

Decolorization - remove colors caused by various dyes, etc.

Filtration – removes some insoluble impurities

Adsorption - adsorption of some impurities dissolved in water

Dangers of hard water:

1. Washing clothes with hard water wastes soap and cannot clean the clothes. It will also harden the clothes over time.

2. Form scale and waste fuel.

3. Destroy the instrument and cause danger.

4. Methods for softening hard water:

Boiling is commonly used in daily life to reduce the hardness of water

Distillation is commonly used in laboratories to obtain distilled water to reduce water hardness.

will you do it

1. Filtration is often used for separation ( )

A. Two immiscible liquids

B. Solid solutes and solvents dissolved in liquids

C. Solids that are insoluble in liquids

D. Two miscible liquids

2. Which of the following mixtures can be separated by filtration ( )

A. Alcohol and water B. Salt and sediment

C. Salt water D. Iron powder and copper powder

3. After natural water undergoes the following purification operations, soft water will definitely be obtained ()

A. Precipitation B. Filtration C. Adsorption D. Distillation

4. Which of the following methods can distinguish between hard water and soft water ( )

A. Observe the color B. Add alum

C. Dissolve salt D. Add soapy water

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For more information about the PPT courseware "Water Purification of Nature's Water", please click on the "Water Purification ppt Nature's Water ppt" tag.

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Update Time: 2024-09-08

This template belongs to Chemistry courseware People's Education Press Ninth Grade Chemistry Volume 1 industry PPT template

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