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Tests for zinc Ion

Zinc is a chemical element with symbol Zn. It is found in various salts like zinc chloride and zinc sulphate as Zn (II) ion. Zinc ions are precipitated as their sulphides by passing hydrogen sulphide gas through their solution. Zinc ions react with sodium hydroxide to form white precipitate of zinc hydroxide and also react with potassium ferrocyanide to form white or bluish white precipitate of zinc ferrocyanide.   This video explains how to test for the presence of zinc ion in a given salt.  

Combination Reaction

Combination reaction is a general category of a chemical reaction and it may be defined as the chemical reaction in which two or more substances combine to form a single substance under suitable conditions. Combination reactions are also known as synthesis because in these reactions new substances are synthesized. Combination reactions involve the formation of new bonds and this process releases a large amount of energy in the form of heat.   This video explains the combination reaction of quick lime with water.  

Preparation of Pure Sample of Potassium Trioxalatoferrate (III)

Potassium trioxalatoferrate (III) is an octahedral transition metal complex with the formula K3[Fe(C2O4)3], in which three bidentate oxalate ions are bound to an iron center. The central iron atom is in the +3 oxidation state. This complex can be prepared by dissolving freshly prepared ferric hydroxide in a solution of potassium oxalate and oxalic acid.   This video explains how to prepare a pure sample of Potassium trioxalatoferrate (III).  

Imbibition by Raisins

Water is the most important constituent of plants and is essential for the maintenance of life, growth and development. Transportation of water into and through a plant takes place by different processes like osmosis, diffusion and imbibition. Imbibition is the process of adsorption of water by substances without forming a solution. Swelling of seeds when immersed in water is an example of imbibition. Itis the temporary increase in the volume of the cell.   Raisins when soaked in water swell up due to imbibition. As a result of absorption or imbibition of water, the size of the raisins increases. The…

Tests for Barium Ion

Barium is a chemical element with symbol Ba. It is found in various salts like barium nitrate, barium sulphate and barium carbonate as Ba2+ ion. In group V, barium ions are precipitated as their carbonates by adding ammonium carbonate to their solution. Barium ion reacts with potassium chromate to form yellow precipitate of barium chromate and it also imparts grassy green colour to the flame.   This video explains how to test the presence of barium ion in a given salt.  

Quantitative Estimation

Quantitative estimation is a branch of analytical chemistry which helps to determine the quantity of a substance present in a given sample. One of the important methods in Quantitative estimation is the Volumetric analysis, also called titration. It is used to determine the unknown concentration of a sample by measuring its volume. In a titration, a solution of unknown concentration is reacted with a solution of known concentration. The solution taken in the burette is called the titrant and the solution taken in the conical flask is called the analyte.   This video explains how to determine the strength of…

Purification of Potash Alum by Crystallization

Potash alum is a double salt of potassium sulphate and aluminum sulphate. It is highly water soluble. To prepare pure crystals of potash alum, dissolve the sample in distilled water and remove the insoluble impurities by filtration. This solution is concentrated to the crystallization point and cooled. Colourless transparent crystals of potash alum separate. The soluble impurities are left behind in the mother liquor. Potash alum has an octahedral geometry.   This video explains how to prepare pure crystals of potash alum form an impure sample through crystallization.  

Distinguish between Mixture and Compound

All matter can be classified into two categories: pure substances and mixtures. A pure substance consists of elements or compounds.Elements are the simplest substances in nature and a compound is formed when two or more elements chemically combined together. The components of a compound lose their individual properties and the properties of a compound are different from their individual components. A mixture is a combination of two or more substances which are not chemically the same. In a mixture, the components are present in any proportion and they can be identified visually within the mixture. The properties of a mixture…

Tests for Manganese Ion

Manganese is a chemical element with symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron. The most common oxidation states of manganese are +2, +3, +4, +6, and +7, though all oxidation states from −3 to +7 have been observed. The most stable oxidation state for manganese is +2, which has a pale pink color, and many manganese(II) compounds are known, such as manganese (II) sulfate and manganese (II) chloride.   This video explains how to test for the presence of manganese (II)…

Characteristics of Plants

The kingdom Plantae consists of different types of plants that are eukaryotic, multicellular organisms having photosynthetic pigments and cell walls. Plants are classified in several different ways based on various external and internal characteristics. Based on these characteristics, plants are classified into multicellular groups such as thalophytes, bryophytes, pteridophytes, gymnosperms and angiosperms.   This video describes the characteristics of spirogyra, agaricus, moss, fern, pinus and an angiosperm.  

Rate of Transpiration

Transpiration is a process that involves loss of water vapour through the stomata of plants. There is a close inter-relationship between transpiration and leaf structure. The rate at which transpiration occurs refers to the amount of water lost by plants over a given time period. Plants regulate the rate of transpiration by opening and closing of stomata. Each stomata has a slit like opening called the stomatal pore, which is surrounded by two special cells called the guard cells. These special cells help to regulate the rate of transpiration by opening and closing the stomata A number of external factors…

Pressure Exerted by a Solid Iron Cuboid on Sand

The mass (m) of an object is a fundamental property of the object. In everyday usage, mass is often referred to as weight. An object’s weight depends on its environment, while its mass does not. In science, the weight of an object is the force on the object due to gravity. The force acting on an object perpendicular to the surface is called thrust. The effect of thrust depends on the area on which it acts. The thrust on unit area is called pressure.   This video explains how to study and compare the pressure exerted by a solid iron…

Chemical Tests for Phosphate

Phosphates are inorganic salts containing phosphate ion. The It contains a central phosphorous atom surrounded by four oxygen atoms in a tetrahedral arrangement. The most well known compound containing phosphate ion is phosphoric acid. Phosphate ions react with ammonium molybdate to produce a characteristic yellow precipitate, ammonium phosphomolybdate.   This video explains how to test the presence of phosphate ion in a given salt.  

Separation of Components of a Mixture

Most of the matter in our surroundings exists as mixtures of two or more components. Examples: Milk, Soil, Sea water. etc. A mixture shows the properties of its constituent elements. The components of a mixture can be separated by physical methods like handpicking, filtration and so on. Sometimes special techniques have to be used for the separation of the components of a mixture.   This video explains how to separate the components of a mixture of ammonium chloride, salt and sand.  

Tests for Group I Lead Ion

Lead is a chemical element with symbol Pb. It is found in lead pencil and lead acid battery. Lead is found in many salts like lead nitrate and lead acetate as lead (II) ion. In group I, lead (II) ions are precipitated as their chlorides by adding dilute hydrochloric acid to their solutions. Lead chloride solution in hot water when reacts with potassium iodide solution to form yellow precipitate of lead iodide and potassium chromate to form yellow precipitate of lead chromate.   This video explains how to test the presence of group I lead ion in a given salt….

Chemical Tests for Oxalate

Oxalates are salts of oxalic acid containing oxalate ion. Oxalate ion is a dianion. Upon protonation, oxalate ion forms a commonly known compound, oxalic acid. The commonly known oxalate salts are sodium oxalate, potassium oxalate etc. The calcium metal ion reacts with oxalate ion to form an insoluble precipitate of calcium oxalate, which is the primary constituent of most of the common kind of Kidney stones.   This video explains how to test the presence of oxalate ion in a given salt.  

Melting Point of Ice

Melting point of a solid is defined as the temperature at which a solid changes into liquid. Melting point of a solid indicates the strength of the force of attraction between the particles of the solid. On heating a solid, its molecule absorbs energy in the form of heat and their kinetic energy increases. As the kinetic energy increase the temperature of the solid increases. As a result, the force of attraction between the molecules decreases and the molecules become more and more separated. This increases the potential energy of the molecule and the particles leave their fixed positions and…

Equivalent Resistance of Resistors (Series)

An electric circuit is simply a closed loop through which charges can continuously move. An electric circuit basically contains a source of electricity, a load resistance, a switch or a key for turning the circuit on or off at one’s convenience. When two or more resistors are connected such a way that one end of one resistor is connected to the starting end of the other, then the circuit is called a Series Circuit. Since the current has only one path to take, the current through a series circuit is the same through each resistor. The total resistance/effective resistance of…

Rate of Respiration

Respiration is the process during which simple carbohydrates, like glucose, break down into simpler substances and liberate carbon dioxide and energy. The compound used, or oxidized, during respiration is called a respiratory substrate. Carbohydrates, fats, and proteins are examples of respiratory substrates, and carbohydrates are the preferred respiratory substrate among them. Respiration produces a great deal of energy that is needed by plants to grow and stay healthy. Excess sugars produced by photosynthesis that are not needed for respiration and growth are stored as starch which can then be converted back to sugars when needed during periods of low light….

To Study the Properties of Acids and Bases

The sour and bitter tastes we find in food are due to the presence of acids and bases. Some naturally occurring acids are: vinegar (acetic acid), citric acid (present in orange and lemon), tartaric acid (present in tamarind), etc. Also our stomach produces hydrochloric acid which helps in the digestion of food. Some commonly used bases are baking soda and tooth paste. Tooth paste is a basic substance used for cleaning the teeth and it neutralizes the excess of acids present in the mouth and prevents tooth decay.   This video explains how to study the properties of acids and…

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