Chemistry

States of Matter

Question:

A neon-dioxygen mixture contains 70.6 g dioxygen and 167.5g neon. If pressure of the mixture of gases in the cylinder is  25 bar. What is the partial pressure of dioxygen and neon in the mixture?

Answer:


ncert-solutions-for-class-11th-chemistry-chapter-5-states-of-matter-29

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States of Matter

Q 1.

Define an ideal gas.

Q 2.

The magnitude of surface tension of liquid depends on the attractive forces between the molecules. Arrange the following in increasing order of surface tension:

water, alcohol (C2H5OH) and hexane [CH3(CH2)4CH3)].

 

Q 3.

Explain the physical significance of vander Waals parameters.

Q 4.

Define boiling point of a liquid.

Q 5.

Define critical temperature of gas.

Q 6.

With regard to the gaseous state of matter which of the following statements are correct?
(a) Complete order of molecules (b) Complete disorder of molecules
(c) Random motion of molecules (d) Fixed position of molecules

Q 7.

The critical temperature (Tc) and critical pressure (Pc) of C02 are 30.98 °C and 73 atm respectively. Can C02(g) be liquefied at 32 °C and 80 atm pressure?

Q 8.

Explain the effect of increasing the temperature of a liquid on intermolecular forces operating between its particles. What will happen to the viscosity of a liquid if its temperature is increased?

Q 9.

Assertion (A): Liquids tend to have maximum number of molecules at their surface.
Reason (R): Small liquid drops have spherical shape.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Q 10.

What will be the minimum pressure required to compress 500 dm3 of air at 1 bar to 200 dm3 at 30 °C?

Q 11.

The behaviour of matter in different states is governed by various physical laws. According to you what are the factors that determine the state of matter?

Q 12.

Name two phenomena that can be explained on the basis of surface tension.

Q 13.

Calculate the temperature of 4.0 moles of a gas occupying 5 dm3 at 3.32 bar (R = 0.083 bar  dm3 K-1 mol-1)

Q 14.

What is SI unit of (i) Viscosity (ii) Surface tension?

Q 15.

Calculate the total number of electrons present in 1.4 g of dinitrogen gas.

Q 16.

What are real gases ?

Q 17.

Name four properties of gases.

Q 18.

What do you mean by aqueous tension?

Q 19.

What is the effect of temperatures on the vapour pressure of a liquid?

Q 20.

Give an expression for the van der Wools equation. Give the significance of the constants used in the equation. What are their units?

Q 21.

For real gases the relation between P, V and T is given by van der Waals equation:
ncert-exemplar-problems-class-11-chemistry-chapter-5-states-of-matter-8

where ‘a' and ‘b' are van der Waals constants, ‘nb' is approximately equal to the total volume of the molecules of a gas.
‘a' is the measure of magnitude of intermolecular attraction.
(i) Arrange the following gases in the increasing order of ‘b'. Give reason. 02, C02, H2, He
(ii) Arrange the following gases in the decreasing order of magnitude of ‘a'. Give reason.CH4, O2, H2

Q 22.

Assertion (A): Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules. .
Reason (R): Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Q 23.

Assertion (A): Gases do not liquefy above their critical temperature, even on applying high pressure.
Reason (R): Above critical temperature, the molecular speed is high and intermolecular attractions cannot hold the molecules together because they escape because of high speed.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Q 24.

A vessel of 120 mL capacity contains a certain amount of gas at 35 °C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at 35 °C. What would be its pressure?

Q 25.

Why does sharpened edge becomes smooth on heating up to melting point?

Q 26.

Value of universal gas constant (R) is same for all gases. What is its physical significance?

Q 27.

One of the assumptions of kinetic theory of gases is that there is no force of attraction between the molecules of a gas.
State and explain the evidence that shows that the assumption is not applicable for real gases.

Q 28.

Density of a gas is found to be 5.46 g/dm3 at 27 °C and at 2 bar pressure. What will be its density at STP?

Q 29.

What is the value of the gas constant in SI units?

Q 30.

What do you understand by laminar flow of a liquid?

Q 31.

What is meant by elastic collision ?

Q 32.

Write van der Waals equation for n moles of a gas.

Q 33.

At 25 °C and 760 mm ofHg pressure a gas occupies 600 mL volume. What will be its pressure at a height where temperature is 10 °C and volume of the gas is 640 mL?

Q 34.

State and explain Dalton’s law of partial pressures. Can we apply Dalton's law of partial pressures to a mixture of carbon monoxide and oxygen?

Q 35.

Under which of the following two conditions applied together, a gas deviates most from the ideal behaviour?
(a) Low pressure (b) High pressure
(c) Low temperature (d) High temperature

Q 36.

One of the assumptions of kinetic theory of gases states that "there is no force of attraction between the molecules of a gas."How far is this statement correct? Is it possible to liquefy an ideal gas? Explain.

Q 37.

Pressure exerted by saturated water vapour is called aqueous tension. What correction term will you apply to the total pressure to obtain pressure of dry gas?

Q 38.

Viscosity of a liquid arises due to strong intermolecular forces existing between the molecules. Stronger the intermolecular forces, greater is the viscosity. Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also give reason for the assigned order in one line.Water, Hexane (CH3CH2CH2CH2CH2CH3), Glycerine (CH2OHCH(OH)CH2OH)

Q 39.

Assertion (A): At constant temperature, PV vs V  plot for real gases is not a straight line.
Reason (R): At high pressure all gases have Z> 1 but at intermediate pressure most gases have Z < 1.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Q 40.

Isotherms of carbon dioxide at various temperatures are represented in the following figure. Answer the following questions based on this figure.
ncert-exemplar-problems-class-11-chemistry-chapter-5-states-of-matter-19

(i) In which state will C02 exist between the points a and b at temperature T1
(ii) At what point will Co2 start liquefying when temperature is T1?
(iii) At what point will C02 be completely liquefied when temperature is T2?
(iv) Will condensation take place when the temperature is T3
(v) What portion of the isotherm at T1 represent liquid and gaseous C02 at equilibrium?

Q 41.

At 0 °C, the density of a gaseous oxide at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

Q 42.

What will be the pressure of the gas mixture when 0.5 L of H2 at 0.8 bar and 2.0 L of dioxygen at 0.7 bar are introduced in all vessel at 27 °C?

Q 43.

What would be the SI unit for the quantity  PV2T2/n?

Q 44.

In terms of Charles’ law explain why -273 °C is the lowest possible temperature.

Q 45.

State Dalton's law of partial pressure.

Q 46.

Give mathematical expression for ideal gas equation.

Q 47.

A certain amount of a gas at 27 °C and 1 bar pressure occupies a volume of 25 m3. If the pressure is kept constant and the temperature is raised to 77 °C, what will be the volume of the gas?

Q 48.

(a) What do you mean by’Surface Tension'of a liquid?
(b) Explain the factors which can affect the surface tension of a liquid.

Q 49.

(a) Why aerated water bottles kept under water during summer?
(b) Which property of liquid is responsible for spherical shape of drop?
(c) Why is moist air lighter than dry air?
(d) Define aqueous tension.
(e) What are units of a and b which are van der Waals constants?

Q 50.

Arrange the following in order of increasing density:
ncert-solutions-for-class-11th-chemistry-chapter-5-states-of-matter-33