CLASS 8 CHEMISTRY CHAPTER 1 LET US ASSESS CHEMISTRY OF CHANGES ENGLISH MEDIUM KERALA SYLLABUS

[00:00:02]Standard chemistry first of question. What changes in the arrangement of particles occur during the following situation?

[00:00:25]Three states of matter.

[00:00:28]Liquid gas.

[00:00:55]Okay. Solid changes to liquid.

[00:01:19]liquid liquid gasid.

[00:01:24]ID liquid gas opposite gasid. for solid changes to liquid. Solid changes to liquid.

[00:02:08]Yes, they transform. They transform.

[00:02:12]They transform from a They transform from a tightly packed tightly tightly packed tightly packed arrangement. Tightly packed arrangement tightly packed arrangement into a into a loosely loosely packed arrangement. Loosely packed the arrangement. loosely packed the arrangement.

[00:02:51]they transform from a tightly packed arrangement into a loosely packed arrangement.

[00:02:58]Okay.

[00:03:00]Liquid changes to gas. Liquid changes to gas.

[00:03:22]Particles become widely widely widely spread. Widely spread out. The particles become widely spread outread.

[00:03:40]Yes. Gas change to liquid.

[00:03:54]Particles. Particles. Particles move.

[00:03:58]Move closer. Move closer together.

[00:04:02]Particle move closer together.

[00:04:12]Question.

[00:04:14]Second question, which is the main form of energy liberated absorbed during the given reaction. Write the type of each of this chemical reaction main form of energy. Main form of energy.

[00:04:42]Heat.

[00:04:54]Write the type of each of this chemical reaction.

[00:05:13]First question. Ammonium chloride and barium hydroxide.

[00:05:18]Chlorideium hydroxide.

[00:05:23]Yes.

[00:05:31]Yes. Heat abs.

[00:05:34]Heat absorbed. Heat absorbed.

[00:05:39]type of clear ammonium chloride and barium hydroxide reacting an iron with copper.

[00:06:11]Yes.

[00:06:16]Electric type.

[00:06:23]Yes. Electrochemical.

[00:06:25]Electro. Electrochemical.

[00:06:28]Electrochemical reaction. Electrochemical reaction.

[00:06:43]Yes. What about the metal to be coated must be connected to the positive terminal.

[00:06:50]If gold is to be coated, goldplaced plate is to be connected.

[00:06:56]Coating a metal with another metal using electricity is known as electrochemical reaction.

[00:07:17]Electrical energy electrochemical reaction. Okay.

[00:07:23]Glowing of firefly. Glowing of firefly.

[00:07:27]Bioluminescent.

[00:07:29]Bioluminescent.

[00:07:30]Bioluminescent.

[00:07:33]Biolumincent.

[00:07:35]Luminescent. Okay. Glowing firefly.

[00:07:49]Bioluminescence.

[00:07:55]Exothermic.

[00:07:57]Exothermic reaction. Exothermic reaction. Clear. Decomposition of potassium perangate. Decomposition of potassium peraganate. Potassium per mang. Decompos.

[00:08:12]Heat absorbed.

[00:08:21]Endothermic reaction. Lightning using electric.

[00:08:39]Electrical energy. Electrochemical energy.

[00:08:56]Heat some crystals of potassium in a dry tube.

[00:09:09]Bring a burning incense stick near the mouth of the testube.

[00:09:34]What do you observe?

[00:09:37]What is the gaseous product for? Which type of reaction is this?

[00:09:52]purple.

[00:09:58]Blackish green powder. Blackish green.

[00:10:02]Blackish green.

[00:10:04]Okay.

[00:10:08]for potassium perish.

[00:10:36]What is the gaseous product for oxygen?

[00:10:45]Which type of reaction is this type of reaction? Yes. Decomposition reaction.

[00:10:52]Decomposition.

[00:10:54]Decomposition.

[00:10:56]Decomposition reaction.

[00:11:02]What do you observe? What do you observe?

[00:11:07]Yes. Purple color of purple. Purple color of purple color of potassium.

[00:11:15]K4 M4 crumbling into K for crumbling changes into blackish greenish green powder. Blackish green powder.

[00:11:40]When stick is When incense stick is brought near the is brought near thee. Brought near the mouth near the mouth of the near the mouth of the test tube. the mouth of the test tube. It burst into it burst into it burst into flames. Flames flames or glows or glows more brightly or more brightly.

[00:12:23]Which is the gaseous product formed for oxygen. Last one. Which type of reaction is this reaction? Thermal decomposition. Thermal decomposition.

[00:12:37]Thermal decomposition reaction. Clearly. Okay.

[00:12:48]A white cloaked silver nitrate darkens when it is kept in sunlight.

[00:12:56]Silver nitrate.

[00:12:58]White cloaked silver.

[00:13:08]Which form of energy is responsible for this change?

[00:13:23]UV. Okay.

[00:13:26]UV.

[00:13:34]What is the general name for this type of reaction? Light reaction. Yes. Photochemical.

[00:13:43]Photochemical.

[00:13:44]Photochemical decomposition. Photochemical decomposition.

[00:13:50]Decomposition.

[00:13:52]Clear.

[00:14:06]photochemical decomposition.

[00:14:08]Photochemical decomposition.

[00:14:12]Last sodium metal react with water to give new substances.

[00:14:29]Which are the reactants in this reaction? Which are the products formed?

[00:14:56]reaction balanced reaction balanced 2 H2O 2 Na balanced. Okay.

[00:15:12]2 Na + 2 H2 NaOH plus H2. Okay.

[00:15:33]Net balancing.

[00:15:39]Okay. Which are the reactants?

[00:15:47]Sodium and water. Sodium water reactants. Which are the products formed? Products formed.

[00:15:58]Sodium hydroxide. Sodium hydroxide.

[00:16:02]Sodium hydroxide. H2.

[00:16:06]Hydrogen gas. Sodium hydroxide. And Hydrogen gas.

[00:16:27]Thank you.