Chemistry Podcast

Sunday, 27 August 2017

Chemistry Formulas for Chemical Bonding



Chemistry Formulas for Chemical Bonding

 
   1.       Necessary condition for an ionic solid to be dissolved in water
                                Hydration Energy > Lattice Energy
   2.       Order of melting and boiling points of certain compounds
NaF > NaCl > NaBr > NaI;    MgO > CaO > BaO
3.       No Bond is 100% Ionic
4.       Force of attraction between two oppositely charged ions in vacuum (air) as per Coulombs Law
F = q1q2/r2
5.       Order of the Lattice Energy of some compounds
·         LiX > NaX > KX > RbX > CsX    (where X = F, Cl, Br, I)
·         MgO > CaO > SrO > BaO
·         MgCO3 > CaCO3 > SrCO3 > BaCO3
·         BaSO4 > SrSO4 > CaSO4 > MgSO4  
·         Mg(OH)2 > Ca(OH)2 > Sr(OH)2 > Ba(OH)2
·         Bivalent Ions-Bivalent Ions > Univalent Ions-Bivalent Ions or Bivalent Ions-Univalent Ions > Univalent Ions- Univalent Ions
6.       Example of some compounds which contains more than one type of bond
·         NaOH, KOH, Na2CO3  (Ionic Bond, Covalent Bond)
·         CO, NH3.BF3, [Co(NH3)3Cl3]  (Dative Bond, Covalent Bond)
·         NH4Cl, CuSO4, K4[Fe(CN)6], [Cu(NH3)4]SO4  (Dative Bond, Ionic Bond, Covalent Bond)
·         CuSO4.5H2O  (Hydrogen Bond, Dative Bond, Ionic Bond, Covalent Bond)
7.       Double bond or triple bond is always shorter than corresponding single bond
8.       As S-Orbital is smaller than P-Orbital so bond length decrease with increase in S-character
SP3  C-H  =  1.093 ร… (as in Alkanes)
SP2  C-H  =  1.087 ร… (as in Alkenes)
SP  C-H  =  1.057 ร… (as in Alkynes)
9.       Bond length increases if size of bonded atom is increases with given atom
HI > HBr > HCl > HF
10.   Bond distance is directly proportional to Atomic size
11.   Order of bond strength (or bond energy) of different hydrogen halides
H-F > H-Cl > H-Br > H-I
12.   Bond energy is directly proportional to bond order
Triple Bond > Double Bond > Single Bond
13.   Formula of Dipole Moment
Dipole moment (ยต) = Electronic Charge (e) x Distance (d)
14.   Unit of Dipole Moment
Debye (D)
1D = 1 x 10-18e.s.u. cm
SI unit of Dipole Moment is = Coulomb-Meter (C-m)
1D = 3.336 x 10-30 C-m
15.   Dipole Moment of some substances
Substance with Formula
Dipole Moment (D)
HF
1.91
H2O
1.84
SO2
1.60
NH3
1.46
NF3
0.24
CH3Cl
1.86
HCl
1.03
H2S
1.10
HBr
0.78
HI
0.38

16.   Formula to calculate percentage ionic character of covalent bond
% Ionic Character = (Observed dipole moment x 100)/Dipole moment for 100% ionic bond
17.   Order of polarizing power of cations
Li+ > Na+ > K+ > Rb+ > Cs+
Be2+ > Mg2+ > Ca2+ > Sr2+ > Ba2+
Al3+ > Mg2+ > Na+
18.   Order of polarizing power of anions
N3- > O2- > F-
P3- > S2- > Cl-
19.   Chemistry Formula of Bond Order
Bond Order = [Nb-Na]/2
Where,
                Na = Number of electrons in antibonding molecular orbitals
                Nb = Number of electrons in bonding molecular orbitals
20.   Some molecules with their bond order, bond length and bond dissociation energy
Molecule
Bond Order
Bond Length (pm)
Bond Dissociation Energy (kJ/mol)
F2
1
142
158
O2
2
121
498
N2
3
110
945

21.   Bond Order in compounds which exhibits Resonance
Bond Order = (Total No. of bonds between two atoms)/(Total No. of resonating structures)


Saturday, 19 August 2017

Science Quiz : Acids and Bases Chemistry MCQs Part 18

Science Quiz : Acids and Bases Chemistry MCQs


Science Quiz by www.ChemistryNotesInfo.com

These are some of the random multiple question answers from Acids and Bases Chemistry...

1. OH- ion is called as:

Hydronium Ion
Hydroxide Ion
Hydrate Ion
Hydrogen Ion


2. Taste of acidic food is:

Sweet
Salty
Sour
Bitter


3. H+ Ion (Hydrogen Ion) is simply a:

Proton
Neutron
Electron
Hydroxide Ion


4. Bases increases concentration of what in water:

H+ Ion
OH- Ion
Both
None


5. Which of the acid from given below choice of acids is more dangerous:

Citric Acid
Carbonic Acid
Hydrochloric Acid
None of the above


6. Which of the given below statement about Alkalis is true:

They cannot neutralise acids
They are all insoluble
They are all acids
They are all bases


7. What happens to litmus paper in basic solutions:

Red litmus paper turns blue
Blue litmus paper turns red
Pink litmus paper turns Black
Black litmus paper turns blue


8. A liquid has a pH of 6.5, so this liquid is:

Weakly acidic
Weakly alkaline
Strongly acidic
Neutral


9. A liquid has a pH of 14, so this liquid is:

Weakly acidic
Weakly alkaline
Strongly acidic
Strongly basic


10. If a solution have pH of 9, then its H+ concentration is:

1 x 10-9 moles/liter
1 x 10-18 moles/liter
1 x 109 moles/liter
1 x 1018 moles/liter



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