"Transformation of Sulfur" Nature and Transformation of Matter PPT (Lesson 1 Sulfur elements in different valence states in nature and the transformations between them)

Description

"Transformation of Sulfur" Nature and Transformation of Matter PPT (Lesson 1 Sulfur elements in different valence states in nature and the transformations between them)

Part One: Literacy Goals

1. Based on application examples in production and life or through experimental exploration, be able to understand the main properties of sulfur and its important compounds from a combination of macro and micro perspectives.

2. Able to clearly explore the purpose and principles of experiments based on the information given in the questions, design experimental plans, conduct experimental investigations, analyze and solve problems that arise during the experiments, and draw correct experimental conclusions. Gradually enhance awareness of scientific inquiry and innovation.

3. Apply redox reaction principles and experiments to study the transformation relationship between sulfur and its important compounds, and cultivate awareness of evidence reasoning and model cognition.

PPT on the transformation of sulfur, part 2: independent preview before class

Knowledge foundation

1.Sulfur element is the main component of black powder. The chemical equation for black powder explosion is

2. Sulfur has different valence states, and substances containing sulfur in the same valence state can pass through each other.

Metathesis reactions transform each other, and substances containing different valence sulfur elements can transform into each other through oxidation-reduction reactions.

3. To explore whether a substance has reducing properties can be verified by reacting it with a suitable oxidizing agent, such as ____________________, which proves that SO2 has reducing properties. To explore whether a substance has oxidizing properties can be verified by reacting it with a suitable reducing agent, such as Fe2O3+3CO_______2Fe+3CO2, which proves that Fe3+ has oxidizing properties.

Preview of new knowledge

1. Sulfur in nature

1. Presence of sulfur

2. Transformation between sulfur elements of different valence states in nature

2. Understanding sulfur element

1. Allotropes of sulfur

Elemental sulfur is commonly known as sulfur, and common allotropes include monoclinic sulfur and orthorhombic sulfur.

2. Physical properties of elemental sulfur

3. Chemical properties of sulfur element

Common valence states of sulfur include -2, 0, +4, and +6. Since sulfur is in an intermediate valence state, it has both oxidizing and reducing properties.

(1) Oxidizing property

(2)Reducibility

4.Uses of elemental sulfur

Elemental sulfur can be used to make sulfuric acid, fertilizers, matches, pesticides, etc.

3. Sulfur dioxide

1.Physical properties

2. Chemical properties

(1)

(2) Reversible reaction: A reaction that can proceed in both forward and reverse directions simultaneously under the same conditions is called a reversible reaction. Substitute "____" for "===" in chemical equations for reversible reactions.

3. Laboratory preparation method

Write the chemical equation of the reaction: Na2SO3+H2SO4(concentrated) === Na2SO4+SO2↑+H2O.

4. Usage: Preparation of sulfuric acid, bleach, disinfectants and preservatives.

[Micro Thought 1] If there is elemental sulfur attached to the inner wall of the test tube, you can add NaOH solution and heat it, then wash it to remove it. Try to analyze the principle of the reaction and write down the chemical equation of the relevant reaction.

Tip: The valence of elemental sulfur is 0, which can either increase or decrease. When reacting with NaOH solution, sulfur undergoes a disproportionation reaction to generate Na2S and Na2SO3 that are easily soluble in water. The chemical equation is 3S+6NaOH==2Na2S+Na2SO3 +3H2O.

[Micro Thought 2] Both CO2 and SO2 are acidic oxides and have certain similarities in properties. Combined with existing knowledge, we will explore whether we can use clarified lime water to identify CO2 and SO2. Why?

Tip: No. When a small amount of CO2 and SO2 are introduced into the clear lime water, white precipitation will occur; when a sufficient amount of CO2 and SO2 are introduced into the clear lime water, the phenomenon will first become turbid and then become clear. The ionic equation for the reaction between SO2 and Ca(OH)2 is SO2+Ca2++2OH- === CaSO3↓+H2O,CaSO3+SO2+H2O === Ca2++2.

[Micro Thought 3] There are two bottles of magenta solution that have been bleached by Cl2 and SO2. How can they be identified through a simple experiment? If equal amounts of Cl2 and SO2 are passed into the magenta solution at the same time, will the bleaching property be enhanced?

Tip: Heating the bleached solution, the solution that returns to red is the magenta solution that has been bleached with SO2, otherwise it is the magenta solution that has been bleached with Cl2.

When equal amounts of Cl2 and SO2 are passed into the magenta solution at the same time, the bleaching property will disappear because Cl2 and SO2 react to form H2SO4 and HCl.

Autonomous testing

1. Which of the following statements about sulfur is correct ()

A. Sulfur is an element needed for plant growth

B. Sulfur element is brittle and easily pulverized, easily soluble in water, and easily melted when heated.

C. Can only exist in nature in a chemical state

D. Sulfur acts as a reducing agent in the explosion of black powder.

Answer:A

Analysis: Sulfur is insoluble in water, item B is wrong; sulfur has both free and combined states in nature, item C is wrong; K2S is generated in the explosion of black powder, the sulfur valence is reduced, and it is an oxidant, item D is wrong.

2. Judge whether it is true or false (mark “√” if it is correct and “✕” if it is wrong).

(1) S is fully burned in a sufficient amount of pure oxygen to generate SO3. ()

(2) When SO2 is passed into the magenta solution, the solution will fade and remain unchanged after heating. ()

(3) Sulfur dioxide has strong reducing properties, so it cannot be dried with concentrated sulfuric acid. ()

(4) Pour SO2 into the BaCl2 solution until it is saturated and no precipitation will occur, then pass in CO2 to produce precipitation. ()

(5) SO2 can discolor acidic KMnO4 solution, reflecting the reducing nature of SO2. ()

(6) Moist Cl2 and SO2 both have bleaching properties, so when they are mixed, their bleaching ability will be enhanced. ()

Answer: (1)×　(2)×　(3)×　(4)×　(5)√　(6)×

PPT on the transformation of sulfur, part three: classroom exploration and learning

Properties of elemental sulfur

Question exploration

1. What are the states of sulfur and the phenomena after heating?

Tip: Sulfur is a yellow or light yellow solid. When heated, sulfur gradually melts into a liquid and finally becomes a gas.

2. Place finely ground iron powder and sulfur powder on an asbestos mesh, ignite them with a hot glass rod, describe the experimental phenomenon and write the chemical equation of the relevant reaction.

Tip: When the mixture is red hot, remove the glass rod, the mixture will continue to remain red hot, and eventually a black solid will be produced. The reaction between sulfur and iron is exothermic, and the reaction will produce black FeS:Fe+S FeS.

3. Describe the reaction between molten sulfur powder and oxygen, describe the experimental phenomenon and write the chemical equation of the reaction.

Tip: The melted sulfur powder burns violently in pure oxygen, emits a bright blue-purple flame, generates a gas with a pungent smell, and releases a large amount of heat: S+O2==SO2.

Knowledge induction

Summary of chemical properties of sulfur element

Analysis of typical cases

Example 1 The correct statement about sulfur is ()

① In the reaction of black powder explosion, the valence of sulfur element decreases and shows reducing properties. ② To separate potassium nitrate, carbon and sulfur in black powder, carbon disulfide, water and filtration operations are required. ③ Sulfur reacts with metals or non-metals as oxidants.

④1.6 g sulfur reacts with 6.4 g copper to obtain 8.0 g pure sulfide

A.①③ B.②④ C.①④ D.②③

Answer:B

Analysis: In the reaction of black powder explosion, the sulfur element obtains electrons and generates K2S, which reduces the valency and shows oxidizing properties. ① is incorrect. The difference in solubility of the three components in black powder can be used to separate the three components of black powder. First, use CS2 to treat the sulfur. Dissolve, filter and evaporate the filtrate to obtain crystalline sulfur. The filter residue is then treated with water to dissolve potassium nitrate and filter. The filter residue is carbon powder. The filtrate is evaporated, concentrated and crystallized to obtain potassium nitrate. ② Correct; when elemental sulfur reacts with metal, Sulfur is used as the oxidizing agent, and S in S+O2 SO2 is used as the reducing agent. ③ is incorrect; when S and Cu react under heating conditions, due to the weak oxidizing property of S, Cu can only be oxidized to Cu2S. The chemistry of this reaction The equation is

2Cu+ S Cu2S

2×64 32 160

6.4 g 1.6 g 8.0 g

That is, 6.4 g Cu and 1.6 g S react exactly to produce 8.0 g Cu2S, ④ is correct.

Point training 1-1 Which of the following statements about the properties of elemental sulfur is correct ()

A. In the reaction between elemental sulfur and elemental metal, sulfur is an oxidant.

B. The reaction between elemental sulfur and elemental metal requires heating or ignition.

C. In the reaction between elemental sulfur and non-metallic elements, sulfur is a reducing agent

D. In the reaction between elemental sulfur and non-metallic elements, sulfur is an oxidant.

Answer:A

Analysis: The valence of metal elements is only positive. The valence of sulfur in metal sulfides must be negative. Elemental sulfur is an oxidant in the reaction with elemental metals. In the conditions of the reaction between elemental sulfur and elemental metals, there is no They are all heated or ignited. For example, the reaction between sulfur and mercury does not require heating; if the elemental sulfur reacts with a weakly oxidizing non-metallic element (such as H2), the sulfur will be oxidizing; if the elemental sulfur reacts with a strongly oxidizing non-metallic element, such as Reacting with O2, sulfur shows reducing properties.

PPT on the transformation of sulfur, part 4: on-site testing

1. Which of the following reagents can identify SO2 and CO2 ()

A. Moistened litmus paper B. Magenta solution

C. Clarified lime water D. HCl solution

Answer:B

Analysis: Both carbonic acid and sulfurous acid can make litmus red, item A is wrong; carbon dioxide and sulfur dioxide can both make clear lime water turbid, item C is wrong; carbon dioxide and sulfur dioxide do not react with hydrochloric acid, item D is wrong.

2. Which of the following substances can cause the magenta solution to fade ()

①Activated carbon ②Sodium peroxide ③Chlorine water ④Sulfur dioxide ⑤Ozone

A.①③④ B.②④⑤ C.①②③④ D.①②③④⑤

Answer:D

Analysis: Activated carbon fades through adsorption, sodium peroxide, chlorine water, and ozone fade through oxidation reactions, and sulfur dioxide fades through the generation of unstable colorless substances.

3. Among the following statements, which one is incorrect ()

A. Sulfur is a yellow, brittle crystal

B. Sulfur compounds are often found in volcanic gases and mineral water.

C. Sulfur is easy to burn, and its combustion products are one of the atmospheric pollutants.

D. Sulfur reacts with iron powder and copper powder respectively to generate divalent metal sulfides.

Answer:D

Analysis: Copper and sulfur react to form +1-valent metal sulfide.

4. Which statement about SO2 is incorrect ()

A.SO2 shows oxidizing properties in some reactions and reducing properties in some reactions.

B.SO2 is an acidic oxide, which can form sulfurous acid when dissolved in water.

C.SO2 can make acidic KMnO4 solution fade, indicating that SO2 has bleaching properties

D. SO2 gas is passed into the magenta solution, and the solution fades.

Answer:C

Analysis: The valence of sulfur element in sulfur dioxide is +4, which can be increased to +6 or reduced to 0. Therefore, sulfur dioxide has both oxidizing and reducing properties. Item A is correct; SO2 is an acidic oxide and is soluble in It can react with water to generate sulfurous acid, item B is correct; SO2 can make acidic KMnO4 solution fade, reflecting the reducing property of sulfur dioxide, item C is wrong; SO2 has bleaching properties, and when passed into a magenta solution, the magenta solution will fade, D The item is correct.

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Update Time: 2024-11-22

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