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How Absorption Refrigeration Works
Просмотров: 157734 Omar Faruque
Potassium - The Active ALKALI METAL!
Please note that this video was made solely for demonstration purposes! Do not attempt to repeat the experiments shown in this video! So today I will show you a few experiments with a very dangerous and expensive metal - potassium. Potassium is an active alkali metal, which is in Group 1 table of chemical elements. Compounds of potassium are essential micronutrients for many living organisms. Pure elemental potassium was obtained in the early 19th century by an English scientist. On the appearance, potassium has a metallic luster, with a slightly bluish tint. It is a very soft metal, about as hard as the butter from a refrigerator. In air, a fresh slice of potassium is being instantly oxidized and coated with a layer of peroxides and carbonates. Potassium is more active than sodium. So if small pieces of sodium react with water more or less calmly, even small pieces of potassium immediately ignite and explode spontaneously. The reaction of potassium and water produces alkali, and hydrogen is released which burns pink flames due to potassium ions. In the slow motion shot you can see how hydrogen is ignited by potassium sparks. The behavior of potassium in the water is very unpredictable. Even small pieces can explode in water powerfully, although on the contrary large ones do not want to blow up and instead they just burn. Do not attempt to play with potassium, it is very dangerous! Because of its high activity potassium may spontaneously ignite in air. I took a small piece of potassium and began to spread it on a napkin. Once the napkin is coated with a thin layer of potassium, the latter reacts with oxygen and ignites, thus potassium superoxide and potassium peroxide are formed. Also, for this reaction a napkin is involved. Because of its high activity, the potassium can pull oxygen from the cellulose molecules that napkins are made of. Potassium can be set on fire, it will burn and form potassium superoxide. If potassium superoxide is dipped in water, it will begin to decompose into oxygen and potassium hydroxide . In the last experiment, I took a small piece of potassium and threw it into a cup with ethanol. Potassium rapidly dissolved in ethanol to form ethanolate, potassium and hydrogen. Subscribe to my channel to learn a lot of interesting things about many different unusual materials and their properties. Facebook: https://www.facebook.com/thoisoi2 Patreon: https://www.patreon.com/Thoisoi?ty=h Music: http://audiomicro.com Instagram: https://www.instagram.com/thoisoi/
Просмотров: 147857 Thoisoi2 - Chemical Experiments!
hiii friends In this video I have explained about simple vapour absorption system. ******************************************************************** The vapour absorption refrigeration system is one of the oldest method of producing refrigeration effect. The principle of vapour absorption was first discovered by Michael Faraday in 1824 while performing a set of experiments to liquify certain gases. The refrigerant, commonly used in a vapour absorption system, is ammonia. ADVANTAGES OF VAPOUR ABSORPTION REFRIGERATION SYSTEM OVER VAPOUR COMPRESSION REFRIGERATION SYSTEM 1. It uses low grade heat energy therefore, it can operate on exhaust from IC engines or on kerosene lamp or an process heat. 2. It has pump only as moving part ,hence ,it is quite in operation. 3. Wear and tear is less 4. Possibility of leakage is very little 5. It can be located outside without shelter DISADVANTAGES OF VAPOUR ABSORPTION REFRIGERATION SYSTEM OVER VAPOUR COMPRESSION REFRIGERATION SYSTEM 1. It has low COP 2. Charging of refrigerant is difficult 3. It is bulky ******************************************************************** If, you liked this video then plz share this video with your friend and subscribe this channel. - THANK YOU
Просмотров: 31150 EASY LEARNING
Lecture -17 Vapour Absorption Refrigeration Systems (Contd.)
Refrigeration and Air Conditioning
Просмотров: 28922 nptelhrd
TOPIC TIMINGS Solids, liquids and gases 0:36 Elements, compounds and mixtures 1:11 The structure of the Atom 1:43 Ionic and Covalent Bonding 5:25 Chemical Structures 6:29 How to Draw Formulae 9:22 Balancing Equations 10:45 Rates of Reaction 12:41 Oxygen and Oxides 13:47 Group 1 metals 13:55 The Halogens 15:35 Transition Metals 17:02 Reactivity Series and Salt Equations 17:31 Titrations 20:46 Making Soluble and Insoluble Salts 20:52 Separating Mixtures 27:58 Positive and Negative Ion Tests 30:17 Collecting Gases 33:13 Electrolysis 33:18 Endothermic and Exothermic Reactions and THE HABER PROCESS 37:37 Blast Furnace 42:58 Rusting of Iron 46:20 Alkanes and Alkenes 47:52 Isomers 53:30 Manufacture of Alcohol 57:08 Addition Polymerisation 57:12 Condensation Polymerisation 58:02 Moles 1:01:36 Enthalpy Calculations - bond making and breaking 1:08:38 Energetics 1:11:56 Electrolysis Calculations 1:14:40 This video is suitable for people sitting exams in 2018 only! Content for higher tier, triple science is included. ********************************* These videos are designed to help with your IGCSE chemistry revision. To keep up to date with my Science with Hazel videos and support: Follow me on Instagram: https://www.instagram.com/sciencewithazel/ Add me on Snapchat: https://www.snapchat.com/add/sciencewithazel Like my Facebook page: https://www.facebook.com/sciencewithazel/ Hazel completed her undergraduate degree at St John's College, the University of Cambridge. She then did a PGCE (Post-Graduate Certificate of Education) before qualifying as a science teacher. She now works full time as a professional tutor. Material required for A* in the current GCSE syllabus is included.
Просмотров: 48264 Science with Hazel