states of matter

Question 1

1 atm = — torr

Answer 1

760 torr or mmHg

Question 2

1 atm = —- Pa or pounds

Answer 2

101.325 kPa
14.7 pounds per inch

Question 3

temperature at which molecular motion ceases and volume of gas is said to be 0 is called

Answer 3

absolute zero
0K = -273.15 C = -469 F

Question 4

one torr is equal to

Answer 4

1 mm Hg

Question 5

1 dm3 of a compound at STP contains — no. of molecules

Answer 5

2.68 x 1022
Avogadro no/ 22

Question 6

Which of the following is the mathematical form of Avogadro’s law?

Answer 6

V = kn

Question 6

The value of compressibility factor for an ideal gas is:

Answer 6

unity

Question 6

Which of the following gas cannot liquefied by Linde’s method

Answer 6

The critical temperature of H2 is so low (-238˚C), that it cannot be achieved by Linde’s method. H2 and He can be liquefied by Claud’s method

Question 6

CO­2 and SO2 are both triatomic molecules but heat of vaporization of SO2 is greater than CO2. This is due to a:

Answer 6

Stronger the intermolecular forces greater will be the heat of vaporization and vice versa. SO2 is a polar gas, so strong attractive forces are present between molecules.

Question 6

Equal volumes of all the ideal gases at the same temperature and pressure contain equal number of molecules. This is in accordance to:

Answer 6

Avogadro’s law

Question 6

Charles’s law is only satisfied if temperature is taken on:

Answer 6

kelvin scale

Question 7

The value of Vander Waal’s constant ‘a’ for gases O2, N2, NH3 and CH4 are 1.360, 1.390, 4.179 and 2.253 l2 atm moles-2 respectively. The gas which can most easily be liquefied is?

Answer 7

NH3
Van der Waal’s constant ‘a’ is an indirect measure of inter-molecular attractive forces. Ammonia contains strong inter-molecular forces of attraction. Inter-molecular hydrogen bonding is absent in other gases.
Hence, the value of van der Waal’s constant ‘a’ is larger for ammonia than compared to other gases.
Hence, ammonia can be most easily liquefied.

Question 8

Which of the following is the mathematical form of Avogadro’s law?

Answer 8

V = kn

Question 8

The value of compressibility factor for an ideal gas is:

Answer 8

unity

Question 8

Which of the following gas cannot liquefied by Linde’s method

Answer 8

The critical temperature of H2 is so low (-238˚C), that it cannot be achieved by Linde’s method. H2 and He can be liquefied by Claud’s method

Question 8

CO­2 and SO2 are both triatomic molecules but heat of vaporization of SO2 is greater than CO2. This is due to a:

Answer 8

Stronger the intermolecular forces greater will be the heat of vaporization and vice versa. SO2 is a polar gas, so strong attractive forces are present between molecules.

Question 9

Equal volumes of all the ideal gases at the same temperature and pressure contain equal number of molecules. This is in accordance to:

Answer 9

Avogadro’s law

Question 9

Charles’s law is only satisfied if temperature is taken on:

Answer 9

kelvin scale

Question 9

The value of Vander Waal’s constant ‘a’ for gases O2, N2, NH3 and CH4 are 1.360, 1.390, 4.179 and 2.253 l2 atm moles-2 respectively. The gas which can most easily be liquefied is?

Answer 9

NH3
Van der Waal’s constant ‘a’ is an indirect measure of inter-molecular attractive forces. Ammonia contains strong inter-molecular forces of attraction. Inter-molecular hydrogen bonding is absent in other gases.
Hence, the value of van der Waal’s constant ‘a’ is larger for ammonia than compared to other gases.
Hence, ammonia can be most easily liquefied.

Question 10

Rate of diffusion of hydrogen is 8 times that of a gas X2. The molecular weight of X2 is?

Answer 10

128

Question 11

Among the following gases which one has the lowest root mean square velocity at 25°C?
A. SO2
B. N2
C. O2
D. Cl2

Answer 11

Chlorine gas has the lowest root mean square speed at 25°C as it has highest molar mass (71 g/mol)
RMS speed is inversely proportional to the square root of molar mass.
Higher is the molar mass of the substance, lower is the root mean square velocity of it.

Question 12

In a closed vessel, a gas is heated from 300K to 600K. The kinetic energy becomes/remains

Answer 12

According to KMT of gases:
“The average kinetic energy of the gas molecules varies directly as the absolute temperature of the gas “When temperature increases from 300K to 600k (double), the kinetic energy also becomes double.

Question 13

Units of van der Waals constant “a” is

Answer 13

SI : atm dm6/mol2
common : Nm4/mol2

Question 14

Crystallites are present in

Answer 14

amorphous solids
crystallite, any of a type of microscopic body occurring in such glassy igneous rocks as obsidian and pitchstone. Crystallites are regarded as incipient or embryonic crystals, though they often have no recognizable crystallographic form and are too small to polarize light.

Question 15

what are solid crystal lattice structures determined by?

Answer 15

x ray crystallography

Question 16

Lattice energy of NaCl is

Answer 16

-787 kJ/mol

Question 17

Based on the type of bonds crystalline solids may be divided into how many types?

Answer 17

Four types:
1) Ionic solids
2) Covalent solids
3) Metallic solids
4) Molecular solids

Question 18

Which solids is generally the hardest one?

Answer 18

covalent solids

Question 19

On the basis of regular arrangements of the 2 constituents, the solids can be divided into how many types?

Answer 19

Two Types:
1. Crystalline solids
2. Amorphous solids

Question 20

lattice energy depends on

Answer 20

LE is directly proportional to charge but inversely to size

Question 21

The structure of sodium chloride is

Answer 21

Face centered cube

Question 22

Transition temperature of Tin (Sn) from gray (cubic) to white (tetragonal) is

Answer 22

13.2 C

Question 23

A malleable solid is one which can be

Answer 23

Converted into thin sheets

Question 24

The transition temperature of KNO₃ rhombohedral to orthorhombic

Answer 24

128.5 C

Question 25

what is meant by transition temperature

Answer 25

The temperature at which two crystalline forms of the same substance can co-exist in equilibrium with each other.

Question 26

Coordination number of face centered cubic structure is

Answer 26

6

Question 27

When 10% urea is present in NaCl solution then which crystal becomes

Answer 27

needle like 1-d

Question 28

The viscosity of an ideal solids is

Answer 28

infinite

Question 29

In orthorhombic crystal, the unit cell dimensions are

Answer 29

a≠b≠c α=β=γ=90°

Question 30

The unit cell dimensions of triclinic crystal is

Answer 30

a≠b≠c α≠β≠γ≠90°

Question 31

Liquid crystals are

Answer 31

Always anisotropic
A crystalline solid maybe isotropic or anisotropic and liquid crystals are always anisotropic because liquid crystal show variations in their coefficient of thermal expansion

Question 32

Crystal lattice of substance can be categorized into

Answer 32

The 14 Bravais lattices are grouped into seven lattice systems: triclinic, monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic.

Question 33

SI unit of surface tension is:

Answer 33

Nm-1

Question 34

Factors on which vapors pressure depends

Answer 34

(a) size of the molecules, (b) temperature, (c) inter molecular forces

Question 35

In order to mention the boiling point of water at 110°C, the external pressure should be

Answer 35

Between 760 torr and 1200 torr

Question 36

what causes lower vapor pressure

Answer 36

intermolecular forces such as hydrogen bonding
and
low temperature

Question 37

When water freezes at 0°C, its density decreases due to

Answer 37

Empty spaces present in the structure of ice
when water freezes it occupies 9% more space

Question 38

The highest temperature at which a substance can exist as a liquid is called?

Answer 38

critical temperature

Question 39

Kerosene is liquid at room temperature due to

Answer 39

Molecular size
Greater the size of molecule, greater the polarizability, greater the forces of attractions.

Question 40

what affects the rate of evaporation

Answer 40

Evaporation is directly proportional to the temperature and the surface area while inversely proportional to the strength of molecular forces

Question 41

Correct order of boiling points

Answer 41

H2O > HF > NH3 > HCl

Question 42

The boiling point of higher alkanes are greater than those of lower alkanes due to the reason that

Answer 42

The polarizability of higher alkanes are greater
As the sizes of the molecules increases the distortion also increases. This increase distortion of electronic cloud creates stronger London dispersion forces and hence the values of thermodynamic parameters increase.

Question 43

what are the units of viscosity

Answer 43

cgs : poise
SI : Pa s or Ns m2-

Question 44

the rms speed at NTP of a gas can be calculated from the expression

Answer 44

sqaure root (3P/d)
(3PV/M)
(3RT/M)

Question 45

a liquid crystalline state exists between 2 temps, melting temp and —— temp

Answer 45

clearing

Question 46

Quartz (SO2) is a —– crystal

Answer 46

covalent

Question 47

liquid crystals are anisotropic fluids whose properties are an intermediate bw

Answer 47

crystals and isotropic liquids

Question 48

liquid that forms convex meniscus in glass tube

Answer 48

mercury

Question 49

london dispersion forces are strongest in (halogens)

Answer 49

Iodine

Question 50

vapor pressure when a liquid boils is

Answer 50

the same for every liquid as it equals to external pressure

Question 51

correct vanderwaals equation

Answer 51

(p + n^2 x a / v^2) x V-nb = nRT

Question 52

formula for finding new volume using temp change

Answer 52

Vf = Vi + (Vi x T/273)
for temp decrease subtract, for increase add