PV $$=$$ nRT is the equation for:

Dalton's law of partial pressures

MCQ Questions for Class 11 Engineering Chemistry States Of Matter Quiz 3

The

$CO_{2}$ gas does not follow gaseous laws at all ranges of pressure and temperature because :

0%
It is triatomic gas
0%
Its internal energy is quite high
0%
There is attraction between its molecules
0%
It solidity at low temperature

The molar volume of

$CO_2$ is maximum at:

0%
$NTP$
0%
$0^o\ C$ and $2.0\ atm$
0%
$127^o\ C$ and $1\ atm$
0%
$273^o\ C$ and $2\ atm$

By ideal gas law, find the approximate volume that will be occupied by 0.5 mole of an ideal gas at 30

$^oC$ and 3

$atm$ pressure (gas constant

$R$

$=$ 0.0821

$L atm / \:mol / \: K$ )?

0%
Less than 1 $L$
0%
5 $L$
0%
10 $L$
0%
15 $L$
0%
More than 20 $L$

Explanation

Volume

$\displaystyle V = \dfrac {nRT}{P} \\ \: V= \dfrac {0.5 \text { moles} \times 0.0821 \text { L atm/ mol K } \times 303 \text { K}}{3 \text { atm}} \\ \: V = \dfrac {12.4 L \text { atm}}{3 \text { atm}}=4.2 \simeq 5 \text { L}$

Note: Here,

$V$ is volume,

$P$ is pressure,

$n$ is the number of moles of gas,

$R$ is the ideal gas constant and

$T$ is absolute temperature.

Find the new volume of the gas, when kelvin temperature and pressure of a fixed amount of gas is doubled?

0%
Twice its original volume
0%
Unchanged
0%
One-half its original volume
0%
One-fourth its original volum
0%
Four times greater than its original volume

Explanation

The new volume of the gas, when kelvin temperature and pressure of a fixed amount of gas is doubled is unchanged.
Volume is directly proportional to the ratio

$\displaystyle\dfrac {T}{P}$ .

$\displaystyle V \propto \dfrac {T}{P}$
When kelvin temperature and pressure of a fixed amount of gas is doubled, the ratio

$\displaystyle \dfrac {T}{P}$ is unchanged and the new volume is same as old volume.

According to the Kinetic-Molecular Theory, the kinetic energy of the molecules increases when they are --------------

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mixed with other molecules at lower temperature
0%
frozen into a solid
0%
condensed into a liquid
0%
heated to a higher temperature
0%
Collide with each other in a container at a lower temperature

Explanation

According to the Kinetic-Molecular Theory, the kinetic energy of the molecules increases when they are heated to a higher temperature.

The kinetic energy is directly proportional to the absolute temperature.
Kinetic energy

$\displaystyle \propto$ absolute temperature.

As temperature increases, kinetic energy increases.
As temperature decreases, kinetic energy decreases.

Which one proposes a relationship between the combining volumes of gases with respect to the reactants and gaseous products.

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Avogadro's number
0%
$P_1V_1=P_2V_2$
0%
$V_1T_2=V_2T_1$
0%
Dalton's Theory
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Gay-Lussac's Law

$=$ nRT is the equation for:

0%
Boyle's law
0%
Charle's law
0%
Ideal gas equation
0%
Combined gas law
0%
Dalton's law of partial pressures

Explanation

Ideal Gas Equation is given as:

$PV = nRT$

where

$P=$ pressure of the gas;

$V =$ volume of the gas;

$n=$ Number of Moles;

$T=$ Absolute temperature;

$R =$ Ideal Gas constant also known as Boltzmann Constant

$= 0.082057$ L atm K

$^{-1}$ mol

$^{-1}$ .

Hence, the correct option is

$\text{C}$

$P_{total} = P_{1} + P_{2} + P_{3} + ....$ which of the following is correct about the expression?

0%
Boyle's law
0%
Charle's law
0%
Ideal gas equation
0%
Combined gas law
0%
Dalton's law of partial pressures

Explanation

Dalton's law states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases

Mathematically, the pressure of a mixture of non-reactive gases can be defined as the summation:

$P_{total}$ =

$P_1+P_2+P_3...$ .

Five litres of gas at

$STP$ have a mass of 12.5

$g$ .What is the molecular mass of the gas?

0%
12.5 $g/mol$
0%
25.0 $g/mol$
0%
47.5 $g/mol$
0%
56.0 $g/mol$
0%
125 $g/mol$

Explanation

No. of moles in five litres of gas at

$STP$

$=$

$5/22.4 \:mol$

and moles

$=$ weight/molecular weight

$5/22.4$

$=$

$12.5/Mw$

$Mw$

$=$

$56 \:g/mol$

A gas is confined in the manometer as shown below. The stopcock is then opened and the highest level of mercury inside the tube moved to a level that is 80

$mm$ above its lowest level. What is the pressure of the gas?

0%
80 $mm \:Hg$
0%
160 $mm \:Hg$
0%
680 $mm \:Hg$
0%
840 $mm \:Hg$
0%
Cannot be determined

Explanation

The pressure of the gas is equal to the sum of the atmospheric pressure and the pressure due to the difference in the mercury level. The pressure of the gas

$= 760 + 80 = 840 \:mm \:Hg$ .

Which of the following pair of gases cannot be separated by diffusion method?

0%
$SO_2$ and $H_2$
0%
$CO_2$ and $N_2O$
0%
$NH_3$ and $N_2$
0%
$CO_2$ and $H_2$

Explanation

Previously we told that,

$D\propto \cfrac { 1 }{ \sqrt { M } }$

Now,

${ M }_{ C{ O }_{ 2 } }$

$=2\times 16+12=44$ g/mol

${ M }_{ { N }_{ 2 }O }$

$=2\times 14+16=44$ g/mol

$\therefore { D }_{ C{ O }_{ 2 } }={ D }_{ { N }_{ 2 }O }$ , as diffusion coefficient of

$CO_{2}$ and

$N_{2}O$ is equal,

$CO_{2}$ and

$N_{2}O$ cannot be separated by diffusion method.

All gases have the same number of moles in the same volume at constant T and P is stated by :

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Boyle's law
0%
Charle's law
0%
Avogardro's law
0%
ideal gas law
0%
Dalton's law

Regarding the kinetic molecular theory, which of the following statement is not true?

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The volume that gas molecules occupy is negligible compared to the volume within which the gas is contained
0%
There are no forces present between gas molecules
0%
Collisions between gas molecules are perfectly elastic
0%
Gas molecules travel in a continuous, random motion
0%
The average kinetic energy of gas molecules is inversely proportional to temperature

The total pressure of a gaseous mixture is equalto the sum of the partial pressures is:

0%
Boyles law
0%
Charles law
0%
Avogadro's law
0%
Ideal gas law
0%
Daltons law

Which one is correct about Gay-Lussac's law?

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V/T $=$ k
0%
P/T $=$ k
0%
PV $=$ k
0%
$P_T=P_1+P_2+P_3$
0%
PT $=$ k

Explanation

According to Gay-Lussac's Law :

$\displaystyle \dfrac {P}{T}= k$

At constant volume, the pressure of a given mass of a gas varies directly with the temperature.

$\displaystyle P \propto T$ (V and n constant)

Hence, the correct option is B.

Calculate the number of iron atoms in a piece of iron weighing

$2.8 g$ . (Atomic mass of iron

$=56$ )

0%
$30.11\times { 10 }^{ 23 }$ atoms
0%
$3.11\times { 10 }^{ 23 }$ atoms
0%
$3.0115\times { 10 }^{ 22 }$ atoms
0%
$301.1\times { 10 }^{ 23 }$ atoms

Explanation

Given that, weight of iron =2.8 g

Atomic mass= 56

moles of iron

$= \dfrac{\text{wt. of iron}}{\text{atomic mass}}=\dfrac{2.8}{56}=0.05\ moles$

1 mole

$= 6.022 \times 10^{23}\ atoms$

0.05 moles

$= 6.022 \times 0.05 \times 10^{23}\ atoms=3.0115 \times 10^{22}$ atoms

Option C is correct.

Gay Lussac's Law of combining volumes is applicable for combustion of carbon.

0%
True
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False

64 g of sulphur dioxide occupies

$22.4\ L$ volume at STP.

0%
True
0%
False

Explanation

Molecular mass of

$SO_2$ is 64.

So, 1 mole (64 grams) of sulphur dioxide will occupy

$22.4\ L$ at STP. ( Avogadro's law)

The value of the Avogadro constant is:

0%
$6.022 \times 10^{13}$
0%
$6.022 \times 10^{22}$
0%
$6.022 \times 10^{23}$
0%
$6.022 \times 10^{24}$

Explanation

Correct Answer: Option C

Explanation:

The value of the Avogadro constant is $6.022 \times 10^{23}$ .

It is a number of atoms or molecules or ions or particles present in one mole of a substance.

Hence, the correct answer is option $C$ .

Which gas law uses pressure, number of moles, temperature, volume and the gas constant (R)?

0%
Boyle's Law
0%
Ideal Gas Law
0%
Combined Gas Law
0%
Charles' Law

Explanation

The ideal gas low equation uses all the terms,

$PV=nRT$

where

$P$ is the pressure

$V$ is the volume

$T$ is the temperature

$n$ is the mole of gas.

Which statement is NOT compatible with the ideal gas law?

0%
Gas particles have no definite volume
0%
Gas temperature depends on particles mass and velocity
0%
Gas particles are in constant, random motion
0%
Gas particles have no mass

Drops are water are created due to-

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air resistance
0%
surface tension
0%
gravity
0%
all of these

Statement I: In the kinetic theory of gases, collisions between gas particles and the walls of the container are considered elastic.
Statement II: Gas molecules are considered pointlike, volumeless particles with no intermolecular forces and in constant, random motion.

0%
Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1
0%
Both the Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1
0%
Statement 1 is correct but Statement 2 is not correct
0%
Statement 1 is not correct but Statement 2 is correct
0%
Both the Statement 1 and Statement 2 are not correct

Which of the following is a possible source of error in the results of this experiment?

0%
Inaccurate weighing of the isopropanol
0%
The presence of bits of broken glass in the flask
0%
Failure to correct for humidity
0%
Misreading of the atmospheric pressure

Two gases A and B are taken in same volume containers under similar conditions of temperature and pressure. In container A, there are '2N' molecules of gas A. How many number molecules does container B have?

0%
2N
0%
4N
0%
N
0%
8N

If the gas particles in a rigid container slow down, what will happen to the pressure inside the container?

0%
Pressure will increase
0%
Pressure will decrease
0%
Pressure will oscillate
0%
Pressure will not change

Explanation

When the gas particles in a rigid container slow down, the temperature of the system also reduces

We know

$P$

$K$

$T$

Hence pressure decreases, as the temperature reduces.

The initial pressure inside the flask is:

0%
near zero (vacuum)
0%
$27\ mm\$ $\displaystyle Hg$
0%
$760\ mm\$ $\displaystyle Hg$
0%

$(760-27)\ mm\ Hg$

Explanation

Since here in the figure given the mercury is at the same height in both the arms containing the sample and the arm is atom to the atmosphere, the pressure inside the flask initially is

$760mHg$ .

Option (C) is correct.

Which gas law is summarized with the following equation?

$({P}_{1}{V}_{1})/{T}_{1}=({P}_{2}{V}_{2})/{T}_{2}$

0%
Boyle's Law
0%
Ideal Gas Law
0%
Combined Gas Law
0%
Charles; Law

Explanation

The formula for the combined gas law can be adjusted to compare two sets of conditions in one substance. In the equation, the figures for pressure (P), volume (V), and temperature (T) with subscripts of one represent the initial condition, and those with the subscripts of two represent the final condition.

$P_1V_1/T_1 = P_2V_2/T_2$

Identify which of the following statements is FALSE?

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The vapor pressure of a liquid decreases with increasing atmospheric pressure.
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The value of an equilibrium constant is dependent on temperature.
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The rate of a spontaneous reaction cannot be determined solely by its Gibbs free energy.
0%
During a phase transition, the temperature of a substance must be constant.
0%
The addition of a catalyst to a reaction at equilibrium has no net effect on the system.

The mass of a non-volatile solute of molar mass 40 g

$mol^{-1}$ that should be dissolved in 114 g of octane to lower its vapour pressure by 20% is :

0%
10 g
0%
11.4 g
0%
9.8 g
0%
12.8 g

Explanation

The mass of a non-volatile solute of molar mass 40 g /mol that should be dissolved in 114 g of octane to lower its vapour pressure by 20% is 10 g.

Let w g of the non-volatile solute is used. Its molar mass is 40 g/mol.

The number of moles of non volatile solute

$\displaystyle = \dfrac {w}{40} =0.025w$ moles.

114 g of octane (molar mass 114 g/mol) corresponds to

$\displaystyle \dfrac {114}{114}=1$ mole.

The mole fraction of non volatile solute is

$\displaystyle = \dfrac {0.025w}{1+0.025w}$ . The mole fraction of non volatile solute is proportional to the relative lowering in the vapour pressure.

$\displaystyle \dfrac {P^0-P}{P^0}=X_B$

$\displaystyle \dfrac {20}{100}= \dfrac {0.025w}{1+0.025\ w}$

$\displaystyle 100 (0.025w)= 20(1+0.025w)$

$\displaystyle 2.5w=20+0.50w$

$\displaystyle 2w=20$

$\displaystyle w=10$ g

Hence, the correct option is

$\text{A}$

Which of the following has more surface tension at same temperature?

0%
Water
0%
Mercury
0%
Ethanol
0%
Glycerin

When applied to law of combining volumes, which of the following is correct about Berzelius hypothesis ?
a) it predicts atoms are indivisible
b)it predicts atoms are divisible
c)it is contrary to Dalton's hypothesis

0%
Only a
0%
Only b
0%
Both a and c
0%
Both b and c

At constant temperature, the behavior of a real gas more closely approximates that of an ideal as its volume increases due to which of the following?

0%
The average molecular kinetic energy decreases.
0%
The molecules have expanded.
0%
The average molecular speed decreases.
0%
The average distance between the molecules becomes greater.

The ideal gas law was first stated by:

0%
Robert Boyle
0%
Jacques Charles
0%
Amedeo Avagadro
0%
Emile Clapeyron

Surface tension is responsible for

0%
Lower layer of water has lower veocity
0%
A small needle can be made to float on the surface of water
0%
Higher layer of water has lower veocity
0%
None of these

Just because you mix two things together does not necessarily mean they will form a homogeneous mixture (a solution). For example, if you add sodium chloride,

$NaCl$ , to a container that has both hexane and water, the

$NaCl$ will dissolve into the water, but will not be found in the hexane

$C_{6}H_{14}$ .
Which of the following statement BEST explains these observations?

0%
Polar water molecules form ion-dipole forces with the ions of $NaCl$ . Hexane, being nonpolar, cannot form these ion-dipole interactions.
0%
Nonpolar hexane molecules tend to repel the ions that make up $NaCl$ .
0%
Nonpolar hexane is less dense that water, so when the two are in the same container, any $NaCl$ that is added to the mixture sinks to the bottom of the container and cannot get into the hexane layer.
0%
Nonpolar hexane molecules and water molecules repel one another.

Explanation

Like dissolve like is a principle behind homogeneous mixing (i,e formation of solution). For example NaCl is ionic (polar) so it get dissolve in

$H_2O$ (polar). but not in haxane (non-polar ) due to ion- dipole interaction between NaCl and

$H_2O$ .

Small insects such as the water strider can walk on water due to which phenomenon (Choose the best one)

0%
viscosity
0%
surface tension
0%
friction
0%
none of these

If common salt is dissolved in water, then the Surface Tension of salt water is

0%
Increased
0%
Decreased
0%
Not changed
0%
First decreases and then increases

For a non-volatile solute:

0%
vapour pressure of solution is more than vapour pressure of solvent
0%
vapour pressure of solvent is zero
0%
vapour pressure of solute is zero
0%
all of the above

Surface tension may be defined as

0%
The work done per unit area in increasing the surface area of a liquid under isothermal condition
0%
The work done per unit area in increasing the surface area of a liquid under adiabatic condition
0%
The work done per unit area in increasing the surface is of a liquid under both isothermal and adiabatic conditions.
0%
Free surface energy per init volume

Explanation

Surface tension of a liquid may also be defined as the work done per unit area in increasing the surface area of a liquid under isothermal conditions:

Mathematically, surface tension of the liquid

$T=\dfrac{W}{\Delta A}$

where

$W$ is the work done to increase the surface area by

$\Delta A$ .

At critical temperature, the surface tension of a liquid is

0%
zero
0%
infinity
0%
the same as that at any other temperature
0%
Can not be determined

Explanation

Eotvos' Rule states that surface tension is a linear function of temperature following the equation,

$\gamma { V }^{ \frac { 2 }{ 3 } }=k({ T }_{ c }-T)$

where

$\gamma$ is the surface tension of the liquid.

Almost all liquids approximately follow this equation.

Thus

$T = T_c$

$\implies \gamma = 0$

Hence critical temperature is defined as the temperature at which surface tension of a liquid is zero.

Rain drops are spherical in shape because of

0%
Surface tension
0%
Capillary
0%
Downward motion
0%
Acceleration due to gravity

Choose the wrong statement from the following?

0%
Small droplets of a liquid are spherical due to surface tension
0%
Oil rises through the wick due to capillarity
0%
In drinking the cold drinks through a straw, we use the phenomenon of capillarity
0%
Gum is used to stick two surfaces. In this process we use the property of Adhesion

The vapour pressure of pure benzene at

$88^oC$ is 957 mm and that of toluene at the same temperature is 379.5 mm. Calculate the composition of benzene-toluene mixture boiling at

$88^oC$ .

0%
$x_{benzene}=0.66; \,x_{toluene}=0.34$
0%
$x_{benzene}=0.34; \,x_{toluene}=0.66$
0%
$x_{benzene} = x_{toluene}=0.5$
0%
$x_{benzene}=0.75;\, x_{toluene}=0.25$

The specific heat of a bivalent metal is 0.The approximate equivalent mass of the metal will be:

0%
40
0%
20
0%
80
0%
10

Explanation

atomic weight =

$\dfrac{6.4}{specific heat}$

atomic weight = 40

equivalent weight =

$\dfrac{40}{2}$ (bivalent)

equivalent mass = 20

Four flasks of 1 litre capacity each arc separately filled with gases

$H_2, He, O_2$ and

$O_3$ . At the same temperature and pressure the ratio of the number of atoms of these gases present in different flasks would be:

0%
1 : 1 : 1 : 1
0%
2 : 1 : 2 : 3
0%
1 : 2 : 1 : 3
0%
3 : 2 : 2 : 1

Vapour pressure of pure

$A(p^0_A)=100$ mm Hg
Vapour pressure of pure

$B(p^0_B)=150$ mm Hg

2 mole of liquid A and 3 mole of liquid B are mixed to form an ideal solution. The vapour pressure of the solution will be :

0%
135 mm
0%
130 mm
0%
140 mm
0%
145 mm

In the reaction,

$N_2 + 3H_2 \rightarrow 2NH_3$ , the ratio of volumes of nitrogen, hydrogen and ammonia is 1 : 3:These figures illustrate the law of:

0%
constant proportions
0%
Gay-Lussac
0%
multiple proportions
0%
reciprocal proportions

$25^oC$ , the total pressure of an ideal solution obtained by mixing 3 mole of A and 2 mole of B, is 184 torr. What is the vapour pressure (in torr) of pure B at the same temperature (Vapour pressure of pure A at

$25^oC$ is 200 torr.)?

0%
180
0%
160
0%
16
0%
100

Explanation

$x_A=\dfrac{n_A}{n_A+n_B}=\dfrac{3}{3+2}=\dfrac{3}{5}=0.6$

$x_B=0.4$

$p=p^0_A+p^0_Bx_B$

$184=200\times 0.6+p^0_B\times 0.4$

$184=120+p^0_B\times 0.4$

$p^0_B=\dfrac{64}{0.4}=160 torr$

Equal volumes of different gases at any definite temperature and pressure have:

0%
equal weights
0%
equal masses
0%
equal densities
0%
equal number of moles

CBSE Questions for Class 11 Engineering Chemistry States Of Matter Quiz 3 - MCQExams.com

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Practice Class 11 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 11 Engineering Chemistry States Of Matter Quiz 3 - MCQExams.com

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Practice Class 11 Engineering Chemistry Quiz Questions and Answers

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