Topic: States of Matter (Test 1)



Topic: States of Matter
Q.1
Physical behavior of the states differs greatly even though chemical behavior of the three states is identical because
A. chemical properties depend on intermolecular non bonding forces whereas physical properties depend on intermolecular bonding forces
B. chemical properties depend on non bonding forces whereas physical properties depend on intermolecular bonding forces
C. chemical properties depend on intramolecular bonding forces whereas physical properties depend on intermolecular nonbonding forces
D. chemical properties depend on covalent bonding forces whereas physical properties depend on energy supplied
Answer : Option C
Explaination / Solution:

chemical properties depend on intramolecular bonding forces whereas physical properties depend on intermolecular nonbonding forces

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Q.2
Which are three important states of matter ?
A. solid, liquid and gas
B. solid, liquid and plasma
C. solid, glasses and gases
D. atoms, molecules and ions
Answer : Option A
Explaination / Solution:

Three phases of matter are : 1. Solid - firm and stable in shape; not liquid or fluid, strongest intermolecular forces. 2. Liquid - A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. Intermediate molecular forces. 3. Gas -Takes the volume of the container, weakest intermolecular forces.

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Q.3
dipole-dipole forces act between molecules that have
A. an induced electrical dipole moment
B. a permanent electrical dipole moment.
C. an electron cloud that causes temporary dipoles
D. a permanent magnetic dipole moment
Answer : Option B
Explaination / Solution:

dipole dipole forces act between molecules that have a permanent electrical dipole moment,the partial charge of one molecule get attracted to the opposite charge of other molecule

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Q.4
Which of the following statements about Hydrogen bond incorrect?
A. In hydrogen bonding H atom becomes partially positive and is attracted to the more negative F atom.
B. In hydrogen bonding H atom becomes partially positive and is attracted to the more negative O atom.
C. In hydrogen bonding H atom becomes partially negative and is attracted to the more positive N atom.
D. In hydrogen bonding H atom becomes partially positive and is attracted to the more negative N atom.
Answer : Option C
Explaination / Solution:

Hydrogen atom covalently bonded to highly electronegative atom such as N,O experience electrostatic field of another highly electronegative atom due to which a partial positive charge is developed on H atom.

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Q.5
The intermolecular force primarily responsible for the condensed states of nonpolar substances is the
A. dispersion force (or London force)
B. hydrogen bond
C. dipole-dipole attraction
D. ion-dipole forces
Answer : Option A
Explaination / Solution:

The intermolecular force primarily responsible for the condensed states of nonpolar substances is the dispersion force (or London force).

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Q.6
The average Kinetic energy and Thermal energy are proportional to the
A. Pressure
B. Specific Heat
C. Absolute Temperature
D. Volume
Answer : Option C
Explaination / Solution:

The average KE and Thermal energy are proportional to absolute Temperature. The kinetic energy is the amount of motion in the atoms and molecules of a substance. The moleculess of the gas gain energy as the temperature increases as there is more motion of the molecules. As the temperature decreases the motion lessens until at absolute zero all motion (kinetic energy) stops.

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Q.7
Three states of matter are the result of?
A. Balance between vanderwaals forces and the London forces.
B. Balance between Hydrogen bonding forces and the London forces.
C. Balance between intermolecular forces and the intramolecular bonding energy of the molecules
D. Balance between intermolecular forces and the thermal energy of the molecules
Answer : Option D
Explaination / Solution:

Three states of matter are the result of balance between intermolecular forces and the thermal energy of the molecules. These two factors differentiate them from each other. For understanding, The strongest intermolecular forces are in solid then in liquid and weakest in gases.

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Q.8
Gases have much lower density than the solids and liquids because ?
A. Distance between the molecules is small compared to solids.
B. Gases contain lower specific enthalpy than solids.
C. Gases do not have intermolecular forces that attract each molecule to another.
D. Thermal energy overcomes on the attractive intermolecular forces.
Answer : Option D
Explaination / Solution:

In gases, molecules are far apart from each other, thermal energy which is a measure of freeness of motion is thus very high resulting in a very large volume for the same mass(compared to solid and liquid). Hence there density is lowest.

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Q.9
At constant temperature, the pressure of a fixed amount (i.e., number of moles n) of gas is?
A. Varies inversely with its volume.
B. Varies as square of its volume.
C. Is constant irrespective of volume.
D. Varies directly with its volume
Answer : Option A
Explaination / Solution:

From ideal gas equation PV=nRT, keeping n and T fixed, P α 1/V. (Boyles Law) Here, T = Temperature P = Pressure α. = sign of Proportionality V = Volume n= number of moles of gas R= Universal gas constant

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Q.10
Charles’ law states that pressure remaining constant, the volume of a fixed mass of a gas is
A. constant irrespective of its absolute temperature
B. directly proportional to its absolute temperature
C. inversely proportional to its absolute temperature
D. directly proportional to square of absolute temperature
Answer : Option B
Explaination / Solution:

P α T (at constant V).

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