Class 11 Chapter 6: Thermodynamics

System:

A system is that part of universe in which we made observations is called system.

Surroundings:

All remaining part of the universe, other than system is called surroundings.
Universe = System + Surroundings

Types of System:

The system is classified on the basis of movement of energy and matter inside or outside the system. I.e. open system, closed system and isolated system.

1.     Open System:

A system in which exchange of matter and energy between the system and surroundings take place, is called open system.
Example:- Reaction in open beaker.

2.     Closed System:

A system in which exchange of energy between the system and surroundings take place but there is no exchange of matter between the system and surroundings takes place, is called closed system.
Example:- Reaction in closed conducting vessel of steel.

3.     Isolated System:

A system, in which no exchange of matter and energy between the system and surroundings take place, is called isolated system.
Example:- Reaction in isolated vessel like thermos flask.

The state of the system

In chemistry, the state of thermodynamic system is described by the measurable or macroscopic i.e. bulk properties of the thermodynamic system.
To learn better, if someone asks, how we can describe the state of a gas?
So to answer this question, we describe the state of a gas by getting information about pressure (p), volume (V), temperature (T) and amount (n) etc. of gas.
So, these variables i.e. p, V, T are known as state variables or state functions.
Why these variables (p, V, T) are called state variables or state functions?
These variables are called state variables or state functions because their values depends only on the state of the system and do not depend on how they are reached on that point.

Internal Energy

Sum of all energies (like chemical, electrical, mechanical etc.) of the system is called internal energy (U) of the system.
Now question is when internal energy of the system changes?
Internal energy of the system changes when,
·        Heat passes into or heat passes out of the system.
·        Work is done on the system or work is done by the system.
·        Matter enters the system or matter leaves the system.

i.       Work

Before learning about effect of work on internal energy we first understand what is Adiabatic system.

Adiabatic system is a system which does not allow transfer of heat through its boundary; means heat can not enters or leave the system.

If 1kJ mechanical work done (case 1) on the system and 1kJ electrical work done (case 2) on the system than change in temperature is same in bath cases.
So, amount of work done on the system produces the same change of state no matter how this work was done.
So,
U = U2 – U1 = Wad
Where,
U = internal energy
U2 = internal energy at state 2 (final state)
U1 = internal energy at state 1 (initial state)
a.     If Wad is positive, then work is done on the system.
b.     If Wad is negative, then work is done by the system.

ii.     Heat

What is heat?

The exchange of energy due to difference in temperature is called heat.

If system allows exchange of heat (conducting walls of the system) then change in internal energy depends on amount of heat transfer between system and surroundings at constant volume when no work is done.
So,
U = q
Where,
U = internal energy
q = heat
Sign of q
a.     q is positive, if heat is transferred from the surroundings to the system.
b.     q is negative, if heat is transferred from the system to surroundings.

Structure of Atom MCQ

These are some of the random multiple question answers from Structure of Atom...

Goldstein
Rutherford
J. Stanley
J. J. Thomson

Rutherford
Austin
Langmuir

0
1
2
3

4.Cathode rays are deflected by :

A magnetic field only
An electric field only
By Both
By None

5. Cathode rays have :

Mass Only
Charge Only
Mass and Charge Both
No Charge and No Mass

6. Mass of atom is mainly constituted by :

Neutrons and neutrino
Neutrons and electrons
Neutrons and protons
Protons and electrons

1.8
1.8x103
Infinite
None of these

8. Atomic number of an element is equal to the number of  :

Proton
Electron
Neutron
Electron and Proton

10-8 m
10-10 m
10-12 m
10-15 m

10.Who modifies Bohr’s model :

Dalton
Pauli
Rutherford
Sommerfeld

11 Class Chapter 2- Structure of Atom

Some Basic Concepts of Chemistry Class 11 MCQ

These are some of the random multiple question answers from Some Basic Concept of Chemistry...

Solid
Liquid
Gas
All of the Above

2. Mole is SI unit of :

Current
Temperature
Amount of Substance
Luminous intensity

11.2 0C

78 0C

102.7 0C

37.8 0C

36 g
18 g
72 g
90 g

5. How many moles of CH4 is needed to get 44 gram CO2 after combustion :

0.5 mol of Methane
1 mol of Methane
2 mol of Methane
4 mol of Methane

10%
20%
30%
40%

0.4 M
1.0 M
0.1 M
4.0 M

111.2 0F

88.8 0F

32 0F

199.8 0F

9. Dalton in 1803, gives :

Law of conservation of mass

Law of definite proportion

Law of multiple proportion

Gay Lussac’s law of gaseous volume

10. The prefix 10-15 is :

Atto
Femto
Peta
Tera

View below video on Some Basic Concept of Chemistry Quiz

11 Class Chapter 1- Some Basic Concept of Chemistry Notes

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)

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...

Hydronium Ion
Hydroxide Ion
Hydrate Ion
Hydrogen Ion

Sweet
Salty
Sour
Bitter

Proton
Neutron
Electron
Hydroxide Ion

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

Weakly acidic
Weakly alkaline
Strongly acidic
Neutral

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

NOTE:

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