It is used to separate and identify piousness food additive or food colours which are not recommended by WHO. It is used to separate and identify even colourless compounds e.
Protein is made up of colourless amino acids on separation they are not visible then a locating agent e. Ninhydrin solution is sprayed on chromatogram due to which different amino acids becomes visible with different colours which are then compared with the standard chart of amino acids hence identified.
This technique is used by forensic scientists to investigate crimes, from the incident place samples are collected which are then compared with the samples collected from suspects if matching occurs then they reach to conclusion. It is also use to identify piousness insecticides which are not recommended by WHO. Various plants pigments e. Will you recommend this book to others. Have you found any Mistakes in this book if any.
Check here to receive our catalog. The book is so nice and has easy understandable terms keep up the good work. Please enter your comment! Let's Change The World Together. Pdfdrive:hope Give books away. NaCl 2. Polyatomic ion should be placed in brackets, e. Fe NO 3 2 Properties 1. Ionic compounds are hard crystalline solids with flat sides and regular shapes because the ions are arrnged in straight rows in strong ionic bonds.
Ionic compounds have very high melting points and boiling points. The strong forces holding ionic compounds prevents them to evaporate easily. Hence, ionic compounds have no smell. In solids, these ions are fixed in place. Ionic compounds are soluble in water but insoluble in organic compounds.
Vice versa is when in organic solvent. H 2 molecule www. H 2 O molecule Hydrogen atom has one valency. To become stable with hydrogen atom, it needs one more electron, just like helium which has 2 valency. When 2 hydrogen atoms join, they share their electrons, on which, the share becomes 2 electrons, which is now a noble gas configuration, being shared between these 2 atoms.
We write the bond as H — H single bond, which means they share an electron pair 2 electrons. Cl 2 molecule Apart from oxygen sharing between oxygen atoms, it can have electrons with other atoms.
Oxygen needs 2 electrons and when bonded with hydrogen, which need an atom each, they combine to provide 2 electrons on both sides of oxygen bonded with hydrogen atoms. Each hydrogen with oxygen atom form a single bond: O — H. CO 2 molecule Cl atom has 7 valency and needs one electron, each, to form a noble gas configuration between two Cl atoms. Hence they share an electron EACH to hence share 2 electrons between the atoms. Hence, each Cl atom now has 8 valency which is a noble gas configuration.
O 2 molecule An O atom has 6 valency and needs 2 electrons, each, to form a noble gas configuration. The contribution hence now become 4 electrons and what left on each oxygen atom is 4 electrons. We combine each 4 electrons on oxygen atom with the 4 electrons shared and hence we get 8 valency for each oxygen atom — a noble gas configuration!
Carbon needs 4, oxygen needs 2. Now oxygen is stable but carbon needs 2 more, which we now know they can get from another oxygen atom. Silicon Dioxide Silicon dioxide, SiO 2 , has silicon atoms bonded with another oxygen atoms in a tetrahedral arrangement which each silicon atom uses all its valence electrons to form 4 single covalent bonds with other 4 oxygen atoms.
Graphite Graphite has flat layers of carbon atoms bonded strongly in hexagonal arrangement in which the layers are bonded to each other weakly. Properties 1. It is a hard solid because it consists of many strong covalent bonds between atoms.
This property makes it suitable as abrasives. It has very high melting and boiling points. It does not conduct electricity except graphite because there are no free electrons in covalent bonds since they are used to form bonds; hence electrons are in fixed positions.
To conduct electricity, there must be free electrons. All covalent structures are insoluble in water. The atoms are packed closely together in giant lattice structures. There are free electrons moving between the spaces and positive metal ions are attracted to the sea of electrons which hold the atoms together.
Metals can be bent ductile and can be stretched malleable because the layers of atoms in metals slide over each other when force is applied but will not break due to attractive force between electrons and metal ions. Metals conduct electricity as it has free electrons which carries current. Metals conduct heat as it has free electrons which gains energy when heated and moves faster to collide with metal atoms, releasing heat in collisions. Metals have high melting and boiling points because the bonds between metals is very strong.
Hence very high heat energy needed to break the bonds. They have low melting and boiling points because the force of attraction is weak that they can be easily broken by heat. Since they have low boiling points, they evaporate easily. Most of these are insoluble in water but soluble in organic solvent.
The mass of the isotope is 12 times greater than hydrogen atom so of carbon atoms is equivalent to the mass of one hydrogen atom. Relative Atomic Mass - the average mass of one atom of the element averaging isotopes when compared with In short is: www. The Relative Atomic Masses are already stated on the periodic table above each chemical formula.
Relative Formula Mass— same as relative molecular mass but for ions only Relative Formula Mass— total A r of all atoms in formula of ionic compound e. Relative formula mass of MgSO 4?
Determine which oxides of iron of Fe 2 O 3 or Fe 3 O 4 has more iron. Therefore to calculate mass of iron in a g compound of iron III oxide is 0. Determine the mass of iron in g of Fe 2 O 3. Calculate water mass in Hence, how many atoms are present? Find the mass of 0. Argon Fluorohydride gas, HArF, first known noble gas compound, has molar mass of 60g.
Find the number of moles Argon atom in 6. C 2 H 6 Empirical Formula — shows the simplest whole number ratio of the atoms present, e. It can be represented by ball-and-stick model or diagrammatically. Ball-and-Stick Diagrammatic Calculating the Empirical Formula of a Compound Find the empirical formula of an oxide of magnesium consisting of 0.
Step 1: find the number of moles of the 2 elements. What is the number of moles of cm 3 of Cl 2 at r. Find the volume of 7g of N 2 at r.
What is the mass of solute in cm 3 of 1. Therefore we multiply product by 2 first. Note: all atoms in molecules are automatically multiplied by 2. However, hydrogen atoms from reactant is short 2 atoms. Therefore, we multiply the hydrogen molecule by 2 so that the short is balanced. The equation is fully balanced when we are able to cancel off all atoms of that element on both sides. Suppose we want to find moles of X atoms that reacted to form 0.
We always put the atom we want to find as numerator and the denominator being the atom we know. To find the reacting mass of X, e. Y is given as 35g, we just multiply the mole by the mass of Y as they are always in ratio: 0. Most other gases are colourless 3. Using above example, to find the concentration of H 2 SO 4 is given on the next page www.
A solution of the acid contain 5. Calculate the percentage purity of the acid. In a titration, To electrolyse it, pass current through the molten PbBr 2. Electrode is a rod or plate where electricity enters or leaves electrolyte during electrolysis. Reactions occur at electrodes.