States of Matter MCQ Quiz - Objective Question with Answer for States of Matter - Download Free PDF

Calculation:

\({V_{rms}}^{2}=\dfrac{3RT}{M}\)

\(V_{a}:V_{b}:V_{c}=1:\dfrac{1}{\sqrt{2}}:\dfrac{1}{\sqrt{3}}\)

\({V_{A}}^{2}:{V_{B}}^{2}:{V_{C}}^{2}=1:\dfrac{1}{2}:\dfrac{1}{3}\)

\(\dfrac{1}{M_{A}}:\dfrac{1}{M_{B}}:\dfrac{1}{M_{C}}=1:\dfrac{1}{2}:\dfrac{1}{3}\)

\(M_{A}:M_{B}:M_{C}=1:2:3\)

Hence, the correct answer is option 5.

CONCEPT:

Avogadro's Law

• Avogadro's law states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.
• The law is often stated mathematically as:

  V ∝ n

  where V is the volume of the gas, and n is the number of moles of the gas.

EXPLANATION:

• Avogadro's law is valid for ideal gases.
• In the context of real gases, Avogadro's law is an approximation that holds true under conditions of low pressure and high temperature where the gas behaves more ideally.
• Van der Waals gases are real gases that have been corrected for intermolecular forces and molecular volumes, and while Avogadro's law can be applied, the deviations from ideal behavior must be taken into account.

Therefore, the correct option is: 2) ideal gas

CONCEPT:

Root Mean Square Speed (Crms) and Most Probable Speed (Cmp)

• The root mean square (r.m.s) speed (Crms) of a gas is given by the formula:

  Crms = √(3kT/m)

• The most probable speed (Cmp) of a gas is given by the formula:

  Cmp = √(2kT/m)

• Here, k is the Boltzmann constant, T is the temperature, and m is the mass of the gas molecule.

EXPLANATION:

• Given:
  • (Crms)H2 at 150 K
  • We need to find the temperature at which (Cmp)He = 1/2 (Crms)H2
• Using the formulas for r.m.s speed and most probable speed:
  • (Crms)H2 = √(3k * 150 / m_H2)
  • (Cmp)He = √(2kT / m_He)
• Given (Cmp)He = 1/2 (Crms)H2, we have:
  • √(2kT / m_He) = 1/2 * √(3k * 150 / m_H2)
  • Squaring both sides:

    2kT / m_He = 1/4 * 3k * 150 / m_H2

  • Solving for T:

    T = (3/8) * (150 * m_He / m_H2)

• Since the molar mass of H2 is 2 g/mol and that of He is 4 g/mol:
  • T = (3/8) * 150 * (4 / 2)
  • T = (3/8) * 150 * 2
  • T = 112.5 K

Therefore, the temperature at which the most probable speed of helium will be half of the r.m.s speed of H2 at 150 K is 112.5 K.

CONCEPT:

Thermodynamic Properties of Gases and Liquids

• The critical point is a state in the phase diagram of substances beyond which the gas and liquid phases are indistinguishable.
• In thermodynamics, the compressibility factor (z) is used to determine how much a real gas deviates from ideal gas behavior. Below the critical point, gases can be liquefied by applying pressure.
• The equation P(V - b) = RT describes the behavior of gases, where P is the pressure, V is the volume, b is the volume occupied by the gas molecules, R is the gas constant, and T is the temperature.

EXPLANATION:

• Statement (A): For solid and liquid, the heat capacity at constant pressure (C_P) is almost equal to that at constant volume (C_V). This is because for solid and liquid states, the volume changes are negligible and do not significantly affect the heat capacity.
• Statement (B): The gas following the equation P(V - b) = RT is described by the Van der Waals equation for real gases. Below the critical temperature, gases can indeed be liquefied by increasing pressure, contrary to the statement's claim. Thus, this statement is incorrect.
• Statement (C): The total energy of an ideal gas molecule consists of its kinetic energy, as ideal gas theory assumes that potential energy and interactions between molecules are neglected.
• Statement (D): Below the critical temperature, the compressibility factor z is less than 1. This is because gases behave non-ideally as they approach the liquid state, and intermolecular forces become more significant. Thus, z < 1 below the critical point. Therefore, this statement is incorrect.

Therefore, the incorrect statements are (B) and (D).

Concept:

• Matter is anything that has mass and volume.
• There are 3 types of matter-
  • Solid- The matter in which the particles are closely paced together.
  • Liquid - The matter in which the particles are less closely packed than solid and more than gas.
  • Gases - In this state of matter, the constituent particles are free for random movement in all directions.

Explanation:

• The intermolecular forces of attraction are strong in solid because the constituent particles are closely packed. So, the shape and size of the solids do not easily change.
• In liquid, the intermolecular forces of attraction in between the molecules are weaker than in solid because the constituent particles are less closely packed. So, the shape and size of the liquids are easily changed.
• The shape of the liquid can be changed easily but the volume of a given mass of liquid is not easy to change and it takes a lot of effort to change the density of the liquid.

Thus, the correct statements are 1, 2, and 4.

Important Points

Concept :

• Food is cooked faster in a pressure cooker because due to high pressure the boiling point of water is raised.
• A pressure cooker works on the principle that with rising pressure the boiling point of water increases.
• Due to the high-pressure boiling point of water rises from 100o C to around 120o C.
• So, the steam also becomes hotter and is also trapped inside the cooker resulting in faster cooking of food.
• When cooked in open vessels the hot air escapes.
• But in the pressure cooker moisture surrounding the food itself reaches higher temperatures than it would without the pressure which speeds the cooking.
• So, the cooking speed is increased nearly four times. 

Hence we can conclude that the beans are cooked faster in pressure cooker because boiling point increase with increasing pressure.

The correct answer is Colloidal.

Key Points

• Features of Liquids:
  • Liquids do not have a definite shape.
  • Liquids have fixed volumes.
  • They can change their shape.
  • Their intermolecular force of attraction is less than solids.
  • The kinetic energy of its particles is more than solids.
• Features of Gaseous: 
  • They can take any shape.
  • Gases neither have a definite shape nor have a fixed volume.
  • Their intermolecular force of attraction is least.
  • The kinetic energy of its particles is maximum.
• Features of Solids:
  •  Solids have fixed volumes.
  • Solids have a definite shape and distinct boundaries.
  • Negligible compressibility.
  • Their intermolecular force of attraction is maximum.
  • The kinetic energy of its particles is minimum.

The correct answer is Ammonia.

Key Points

• Vapour density for ammonia is 8.5 while for chlorine is 35.5, HCl is 18.25 and oxygen is 16. Hence option c is correct

Important Points

• The molecular weight of carbon dioxide is 44. The molecular weight of carbon dioxide is more than the molecular weight of nitrogen. Hence option A is Incorrect.
• The molecular weight of the chlorine molecule is 71. The molecular weight of the chlorine is more than the molecular weight of the nitrogen. Hence option D is incorrect.
• The molecular weight of the oxygen molecule is 32. The molecular weight of oxygen is more than the molecular weight of nitrogen. Hence option B is Incorrect.
• Additional Information
• The molecular weight of the Hydrogen molecule is 2. The molecular weight of hydrogen is less than the molecular weight of nitrogen.
•  hydrogen gas is a lighter gas than air. We should calculate the molecular weight of the compounds to know whether they are lighter than the air or heavier than the air. The molecular weight of some elements is as follows. The Atomic weight of the hydrogen is 1.

The correct answer is It depends on the room temperature.

Key Points

• The boiling point of a liquid depends on: 
  • the temperature, not the room temperature.
  • the atmospheric pressure,
  • It depends on the nature and purity of the liquid.
  • the vapor pressure of the liquid. 
• The normal boiling point is the temperature at which the vapor pressure is equal to the standard sea-level atmospheric pressure, at sea level, water boils at 100° C (212° F).

CONCEPT:

Surface tension: 

• Surface tension is the tension of the surface film of a liquid caused due to the attraction of the particles in the surface layer by the bulk of the liquid, which tends to minimize surface area.
• It is defined as the ratio of the surface force F to the length L along which the force acts.

​\(\Rightarrow T=\frac{F}{l}\)

Where T = surface tension

• When impurities are added to the water the intermolecular distance increases due to which van der wall forces decrease, so the surface tension decreases on adding impurities to the water.

EXPLANATION:

• Surface tension is given as,

\(\Rightarrow T=\frac{F}{l}\)     -----(1)

• By equation 1 it is clear that the surface tension does not depend on the area.
• Surface tension decreases with the increase in temperature.
• The decrease of surface tension with an increase in temperature results because of the kinetic energy (or speeds) of the molecules increases. Thus, the strength of intermolecular forces decreases resulting in the decrease of the surface tension.
• Hence, option 4 is correct.

The rate of evaporation depends on temperature, the presence of wind, the humidity of the surrounding, and the surface area of the liquid exposed to the atmosphere. It doesn't depend on the mass of the liquid.

• The larger the surface area, the more would be the rate of evaporation.
• The higher the humidity, the slower would be the rate of evaporation.
• The higher the presence of wind, the faster would be the rate of evaporation.
• The higher the temperature, the faster would be the rate of evaporation.

The correct answer is Low compressibility 

Key Points

• Gases exert pressure equally in all directions. 
• The gas particles have a very weak attractive force between them and move randomly ultimately exerting pressure in all directions.
• The gaseous state of matter occurs between the liquid and plasma states. 
• Gases that contain permanently charged ions are known as plasmas.

Additional Information

• In a gas, particles are in continual straight-line motion. 
• The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely from each other, hence volume is Not fixed.
• Compared to the other states of matter, gases have low density and viscosity.

CONCEPT:

Vander-Waals equation

• The equation is basically a modified version of the Ideal Gas Law which states that gases consist of point masses that undergo perfectly elastic collisions.
  • However, this law fails to explain the behavior of real gases. Therefore, the Van der Waals equation was devised and it helps us define the physical state of a real gas.
  • Van der Waals equation is an equation relating the relationship between the pressure, volume, temperature, and amount of real gases. For a real gas containing ‘n’ moles, the equation is written as,

​\(\Rightarrow \left ( P+\frac{an^{2}}{V^{2}} \right )\left ( V-nb \right )=nRT\)     -----(1)

Where P, V, T, n are the pressure, volume, temperature, and moles of the gas and  ‘a’ and ‘b’ constants specific to each gas

Rearranging the above equation, we get 

\(P = \dfrac{nRT}{V-nb} - \dfrac{n^2 a}{V^2}\)

The correct answer is Random

Explanation:-

• Each molecule or atom in a gaseous sample behaves independently of the others. Therefore, they are equally likely to travel in any direction at any given time, making their motion random.
• Gas particles are in constant motion and share a large number of rapid, elastic collisions. These collisions are perfectly efficient, meaning they don't lose kinetic energy.
• Kinetic theory of gases assumes randomness: According to the kinetic theory of gases, the motion of gas particles is random, with their direction and speed constantly changing due to collisions with other particles and the container walls.
• The intermolecular space in gases is much larger than in solids or liquids. This property gives gas molecules freedom to move randomly without a fixed path.
• The speed at which gas particles move is influenced by temperature and pressure. Higher temperature means more kinetic energy and faster, more random motion. Inversely, higher pressure can hinder their movement, but not the random nature of it.
• No significant intermolecular forces: Unlike in liquids and solids, intermolecular attractive forces in gases are negligible because particles are far apart from each other. Therefore, they are free to move in a random manner.
• 

Conclusion:-

So, The motion between the particles in a gaseous substance is Random

Explanation:

States of Matter and Phase Change: Substances change their states/phases with the change in temperature.

Several processes of phase change:

• Melting: It occurs when a substance changes from a solid to a liquid.
• ​Vaporization: It occurs when a substance changes from a liquid to a gas. 
• Condensation: It occurs when a substance changes from a vapor to a liquid.
• Sublimation: It occurs when a substance changes from a solid into a gas.
• Deposition: It occurs when a substance converts directly from its gaseous state to a solid state.
• Fusion: It implies the conversion from solid-state to liquid (melting) as well as from liquid-state to solid-state (freezing).

Additional Information

• Evaporation vs Vaporization: Evaporation is a specific type of vaporization, where phase change (liquid-> gas) occurs only at the surface of the liquid. 
• Common examples of Sublimation
  • Dry ice (a frozen form of carbon dioxide)
  • Naphthalene (organic compound).