chemistry for grade 7\\

In 1909, Sorensen introduced a term for expressing the concentration of hydrogen ions, which give an idea about the acidic and basic characters of the aqueous solution. This term was called 'pH' which means the 'power of hydrogen ions'. The pH is defined as "the negative logarithm of the H 3 O + io..

Borax is a colorless, crystalline solid sparingly soluble in cold water but dissolves readily in hot water. It forms two important hydrates: octahedral borax Na 2 B 4 O 7 .5H 2 O and monoclinic borax Na 2 B 4 O 7 .10H 2 ..

Hydrogen Ion Concentration - In 1909, Sorensen introduced a term for expressing the concentration of hydrogen ions, which give an idea about the acidic and basic characters of the aqueous solution. This term was called 'pH' which means the 'power of hydrogen ions'. The pH is defined as "the negativ..

Let, The mass of the organic compound taken be = W g Mass of Mg 2 P 2 O 7 obtained = W 1 g From stoichiometry, Mg 2 P 2 O 7 = 2P 1 mol 2 mol 1 x molecular mass 2 x atomic mass 222 g 2 x 31 g = 62 g Therefore, Then, ..

We have seen that concept of ionic product of water enables us to classify solutions as acidic, basic or neutral by specifying H 3 O + ion concentration. The pH scale was devised by P.L Sorensen (1909) is defined as negative logarithm of hydronium ion concentration in moles per litre. For pur..

The last electron enters into 5f-orbital in these elements. The electronic configuration of actinides is given below. The general electronic configuration of these elements is 5f 1 - 1 4 6d 0 - 1 7s 2 . Element Symbol Atomic number Electronic configuration Actiniu..

The electronic configurations of some of the elements are detailed below. How many valence and core electrons do the following have? Al: 2, 8, 3 Mg: 2, 8, 2 Cl: 2, 8, 7 Ca: 2, 8, 8, 2..

Experimentally it is determined that the mass of an atom is very small ranging from 1.7 x 10 - 2 4 g to about 4.0 x 10 - 2 2 g. These small masses are terribly impractical to work with. Thus, it became necessary to reduce the atomic masses into simple figure..

When the combining atoms have 4, 5, 6, or 7 electrons in the outermost or valence shell, they cannot donate electrons. Instead, they mutually share electrons in order to complete their octet in the outermost orbit or shell. Such a type of valency is referred to as covalency and the ..

Sulphur trioxide dissolves in concentrated sulphuric acid to form fuming sulphuric acid or pyro sulphuric acid or oleum. The properties of sulphur trioxide are summarized in the figure 7.10. ..