مصادر الكيمياء موقع لتعليم الكيمياء بصورة مبسطة

Hybridization :  is a mathematical concept which implies for the mixing of various atomic orbitals with slightly different energies of the same atom to construct equal number of hybrid (mixed) orbitals of equal energy, in a molecule. For an isolated atom, however. the hybridization has no meaning. Hybridization involves promotion of electron from a lower energy state to a higher …

Hydrogen bond: It is a bond formed between a hydrogen atom attached to a highly electrovalent atom (F,O,N) and another highly electronegative atom of the same or different molecule and having a lone pair of electrons. Condition for hydrogen bonding : (i) The electronegative atom attached to the hydrogen should be small. (ii) The electronegativity of the atoms to which …

Difference between σ and π bonds σ bond π bond (i) The orbitals overlap along their axes. (ii) The overlap is quite appreciable and the bond formed is a strong bond. (iii) s-orbitals can parti­cipate in the bond formation. (iv) In case of p-orbitals, the participating lobe is stretc­hed and the  size of the other lobe is reduced. (v) The …

Chemical bond: The attractive force which holds together the constituent atoms of chemical compounds is called chemical bond. Combination of atoms: It. is universal law of nature that systems with lower energy are more stable. So atoms combine to form a molecule because it has a· lower energy i.e., more stable. Modern concept of chemical bonding: The formation -of a …

According to Newton’s corpuscular theory, light is propagated as a stream of particles, called corpuscules. This could justify the phenomenon of reflection and refraction of light but failed to explain the phenomenon of diffraction, interference etc. Clerk Maxwell suggested that light waves are associated with both electric and magnetic fields i.e., light may be described as electromagnetic waves or radiations. …

Chemical nomenclature is the system of names that chemists use to identify compounds precisely. The systematic method of naming compounds is vital to the study of chemistry, because when a new substance is formulated, it must be named in order to distinguish it from all other substances. Using this systematic method of naming compounds, the positive part is named and …

Because the individual atoms in a compound are combined in integer ratios, and each element has a specific atomic mass, it is possible to use mole calculations to determine chemical formulas. The two types of chemical formulas are molecular formulas and the empirical formulas. – Often, the empirical formula is the same as the molecular formula. The molecular formula shows …

The percentage composition of a compound is the percent by mass of each element in the compound. How do we calculate the percent composition? Here are the steps: Calculate the molar mass of the compound.       2.Divide the molar mass of each element by the molar mass of the compound and multiply by 100%. For example, here is …

Molar mass  means the mass of one mole. The molar mass concept can be applied to elements and to compounds. Molar mass is expressed in grams. For example, one mole of carbon has amass of 12 grams. Therefore, carbon’s molar mass is 12 grams. This is equivalent to the statement that 6. 02 x 1023 atoms of carbon have a mass …

The concept of mole is extremely useful in chemistry. The mole is a term like dozen. Dozen means 12. The mole means 6.02 x 1023. It is convenient for chemists to use a concept like mole which represents such a large number since they deal in very small and very numerous quantities. The mole is also called Avogadro’s number. Avogadro’s …