According to Newton’s Second Law of Motion, the force acting on a body is directly proportional to the product of the mass of the body and the acceleration produced in the body by the application of the force. The acceleration takes place in the direction in which the force acts. Newton’s Second Law of Motion precisely explains the relationship between force and acceleration. This video explains how to establish relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance.
Nickel is a chemical element with symbol Ni and atomic number 28. The most common oxidation state of nickel is +2, but compounds of Ni (0), Ni (I), and Ni (III) are well known. It is found in various salts like Nickel chloride, Nickel nitrate and Nickel carbonate as Ni (II) ion. Nickel ions are precipitated as their sulphides by passing hydrogen sulphide gas through their solution. Nickel (II) ions react with dimethylglyoxime to form bright rose-red coloured Nickel-Dimethylglyoxime complex and they react with excess of NaOH and bromine water to form a black precipitate of Nickelic hydroxide. This…
The speed of a reaction or the rate of a reaction is defined as the change in concentration of a reactant or product in unit time. It can be expressed as, the rate of decrease in concentration of any one of the reactants or the rate of increase in concentration of anyone of the products. The speed of a reaction or the rate of a reaction is defined as the change in concentration of a reactant or product in unit time. It can be expressed as, the rate of decrease in concentration of any one of the reactants or the…
Displacement reaction is a chemical reaction in which a more reactive element displaces a less reactive element from its compound. Both metals and non-metals take part in displacement reaction. An example of a single replacement reaction is the reaction of iron nails with copper sulphate solution. An important thing to remember with single displacement reaction is that elements that form cations can only displace cations and elements that form anions can only displace anions. There are two types of single displacement reactions : (a) Cation Replacement Reaction and (b) Anion Replacement Reaction. In cation replacement reaction, one cation replaces another…
Protein is an important macronutrient essential for survival. They are constituent of calls and hence are present in all living bodies. 10-35% of calories should come from protein. Protein is found in meats, poultry, fish, meat substitutes, cheeses, milk etc. Proteins are large biological molecules composed of α-amino acids (Amino acid in which amino group is attached to α-carbon, which exist as zwitterions and are crystalline in nature). They contain carbon, hydrogen, oxygen, nitrogen and sometimes phosphorus and sulphur. This video explains some simple tests of proteins.
Copper is a chemical element with the symbol Cu. It is found in many salts like copper sulphate, copper chloride and copper carbonate as Copper (II) ion. In group II, copper (II) ions are precipitated as their sulphides by passing hydrogen sulphide gas through their solution. Copper (II) ions produce a deep blue coloured complex on reaction with ammonium hydroxide and the blue coloured complex then reacts potassium ferrocyanide to form a chocolate brown precipitate of copper ferrocyanide. This video explains how to test for the presence of copper (II) ion in a given salt.
Animals are multicellular organisms that are made up of eukaryotic cells and come under the kingdom Animalia. They have a well developed sensitive nervous systems and the ability of locomotion. Animals need to ingest other organisms, or their products, for sustenance because they do not perform photosynthesis. Animals are adapted to the conditions of the habitats in which they live. There are three major types of habitat: (a)Terrestrial (land) (b)Aquatic (water) (c) Aerial or arboreal (air or tree). Animals also depend on their physical features to help them move about, obtain food, and keep safe. These physical features are called…
Metals are elements and are good conductors of heat and electricity. Most of the metals are electropositive in nature and the metal atoms lose electrons in chemical reactions to form cations. The more reactive a metal, the greater tendency it has to form a positive ion in a chemical reaction. A more reactive metal readily reacts with other elements. The most reactive metals will react even with water while the least reactive metals will not react even with acid. This video explains the action of Zn, Fe, Cu and Mg metals on the solutions of copper sulphate, zinc sulphate…
A sonometer is an apparatus used to study the transverse vibrations of stretched strings. It is in the form of a hollow wooden rectangular box. On the wooden rectangular box there are two bridges and a pulley at one end. A wire string is attached to one end of the wooden box, run over the bridges and pulley and carries a weight hanger at the free end. A sonometer is used to determine the frequency of alternating current. A step down transformer is used for the determination of frequency of A.C. because the voltage of the A.C. mains is 220V,…
Calcium is a soft gray alkaline earth metal with symbol Ca. It is found in various salts like calcium chloride, calcium nitrate and calcium carbonate as Ca2+ ion. In group V, calcium ions are precipitated as their carbonates by adding ammonium carbonate to their solution. Calcium ion reacts with ammonium oxalate to form a white precipitate o calcium oxalate and it imparts brick red colour to the flame. This video explains how to test for the presence of calcium ion in a given salt.
Sulphites are compounds containing sulphite ions. In sulphite ion, the sulphur atom is doubly bonded to one oxygen atom and singly bonded to other two oxygen atoms. There is also a non-bonded lone pair of electrons on the sulphur. Sulphites are often used as preservatives in dried fruits, preserved radish and dried potato products. This video explains how to test the presence of sulphite ion in a given salt.
Decomposition is a type of chemical reaction and it may be defined as the reaction in which a single compound splits into two or more simple substances under suitable conditions. It is just the opposite of the combination reaction. The digestion of food in our body is accompanied by a number of decomposition reactions. There are three types of decomposition reactions : Thermal, Electrolytic and Photo decomposition reactions. Thermal decomposition is a chemical reaction where a single substance breaks into two or more simple substances when heated. Electrolytic decomposition may result when electric current is passed through an aqueous solution…
Magnesium is a chemical element with symbol Mg. It is found in various salts like magnesium chloride and magnesium sulphate as Mg2+ ion. In group VI, magnesium ions form a precipitate of magnesium ammonium phosphate with ammonium phosphate solution. Magnesium ions react with ammonium phosphate in presence of ammonium chloride and ammonium hydroxide to form white precipitate of magnesium ammonium phosphate. This video explains how to test for the presence of magnesium ion in a given salt.
In chemistry, carbonate is an inorganic salt, characterized by the presence of carbonate ion, in which a carbon atom is surrounded by three oxygen atom in a triangular planar manner. Carbonate minerals are found in sedimentary rocks. The most common is calcite, the main component of limestone. Salts of carbonates like sodium carbonate and potassium carbonate are used for cleaning and preservation, as well as for the manufacturing of glass. This video explains how to test the presence of carbonate ion in a given salt.
Water covers about three-quarters of the earth’s surface and it is essential for all known forms of life. Water is a habitat for a variety of plants and animals which have special adaptations to survive in their habitats. Some of the characteristics that control the quality of water are the turbidity of water, pH of water and different types of plants and animals and their density. Turbidity is the measure of the relative clarity of a liquid. Turbidity of the water body determines the depth to which light can penetrate and thus affects the distribution and photosynthesis of phytoplankton…
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 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.
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).
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…
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.