Gram molecular weight.
Answer:- It is the molecular weight of a substance expressed in grams or it is the weight in grams which is numerically equal to its molecular weight.It is also called gram molecule or simply one mole of a substance.
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Dulong and Petit's law.
Answer:- It states that “the product of atomic weight and specific heat of an element is approximately equal to 6.4.” Mathematically, Atomic weight × Specific heat = 6.4
What is chemistry 🧪 ?
Answer:- Chemistry is a branch of science which deals with the study of the composition of matter and the chemical changes involved in it.
Effective nuclear charge ?
Answer :- The part of nuclear charge which is experienced by the outer most electron is known as effective nuclear charge.
What is Hydration energy ?
Answer:- It is the amount of energy released when ionic substance is dissolved and it's constituent ions are hydrated or surrounded by water molecules.
What is electronegativity ?
Answer:- It is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.It is the property of a bonded atom.Fluorine is the most electronegative whereas cesium is the least electronegative element in the whole periodic table.
Why the tyre of an automobile 🚗 is inflated to lesser pressure in summer than in winter ?
Answer:- In summer the room temperature is much higher as compared to winter. Consequently,the same volume of air will exert greater pressure in summer than in winter.(because according to Lussac's law at constant volume, pressure directly proportional to temperature 🌡️).Therefore to avoid the bursting of tyres it is always advisable.
What is redox reaction ?
Answer:- A reaction in which oxidation (loss of electron) & reduction(gain of electron) occur simultaneously is called redox reaction. e.g
What is Quantum numbers ?
Answer:- Quantum numbers are index(whole no.) numbers which are used to specify the position and energy of an electron in an atom.It provide detailed address of an electron in an atom.It is are of four types (I) principle Quantum numbers (II) Azimuthal Quantum numbers (III) Magnetic Quantum numbers (IV) Spin Quantum numbers
What is law of definite proportion ?
ANSWER:- It states that a chemical compound always contains it's component elements in a fixed ratio it does not change with change in their source and their methods of preparation.
What is Limiting reagent ?
Answer:- The reagent (or reactant) which is consume first in a chemical reaction is called limiting reagent. ★The limiting reagent stops the chemical reaction and no further products are formed.
Why halogens have maximum electron gain enthalpy ?
Answer:- Halogens are have small size with high nuclear charge as a concequence they rapidly accept one electron to attain noble gas configuration.Therefore halogens are have maximum negative gain enthalpy.
Why noble gases are very low boiling point ?
Answer:- All the noble gases are monoatomic. They have very low boiling points because the only type of interatomic interaction is weak dispersion force which arise due to very close contact of noble gases.Therefore low temperature needed to overcome their interaction. ★Helium has the lowest boiling point than any known substance.
What is a alloy ?
Answer:- Alloys are made by mixing two or more elements at least one of which is metal. An alloy shows the properties of their constituent elements therefore an alloy is called mixture of components.(This property of alloys separate it from the ionic compounds e.g NaCl) Alloys cannot be separate by physical means. e.g Brass alloy→(copper-zinc) Bronze alloy→(copper-tin) Steel alloy→(Iron-carbon) →Stainless steel alloy is made up of(74% iron+18%chromium+8% nickel)
What is enthalpy of atomisation ?
Answer:- Enthalpy of atomisation is the amount of enthalpy change(energy change) when all the bonds of a compound is broken into their constituent atoms. The compounds may be interatomic molecules or any other molecules.
What is isotones ?
Answer:- Atoms of different elements having same number of neutrons are called isotones. e.g Si & P Atomic no. of si is 14 Atomic mass is 30 Neutron=30-14=16 Similarly, Atomic no. of P is 15 Atomic mass is 31 Neutron=31-15=16 Both have same no. of neutron so they are called isotones.
why graphite conducts electricity ?
Reason:- Both Graphite and diamond belongs to covalent solid but dimond does not conduct electricity. But Graphite conduct electricity due to its typical structure. look at the structure of graphite. Carbon atoms are arranged in layers and each atom is covalently bonded with three carbon atoms in the same layer.The forth valence electron of each atom is present in different layers and is free to move about.these free electrons make graphite a good conductor of electricity. A re you satisfied by this answer
Though nitrogen exhibits +5 oxidation state it does not forms penthalide.why?
Reason:- Nitrogen with n=2 have only s & p orbitals.it does not have d orbital to expands it's covalence beyond four. That is why it doesn't form penthalides.but phosphorus have vacant d orbital in their valence shell so it forms pentahalides. Are you satisfied by this answer.
what is ionisation enthalpy?
Answer:- The minimum amount of energy required to remove an electron from the valence shell of an isolated gaseous neutral atom is called ionisation enthalpy or energy. Ionisation enthalpy decreases down the group due to gradual increase in atomic size.down the group effective nuclear force decreases on valence electron so ionisation enthalpy is less as compared to top elements of that group.
what is electronegativity?
The tendency of an atom to attract bond pair of electrons towards it's self is called electronegativity. Electronegativity value in general decreases down the group with increase in atomic size.however amongst the heavier elements the order is not that much pronounced. fluorine is most electronegativity element in periodic table while ceasium & francium are least electronegativity element.