Question

20) The normal boiling point for H2Se is higher than the normal boiling point for H2S . This can be explained by

A) larger dipole-dipole forces for H2Se .

B) larger dispersion forces for H2Se .

C) larger hydrogen-bond forces for H2Se .

D) larger dipole-dipole forces, larger dispersion forces, and larger hydrogen-bond forces for

21) Choose the substance with the lowest surface tension.

A) CH3SH

B) CH3CH2CH2CH3

C) C6H6

D) H2O

E) (CH3)2CO

22) Which of the following statements is FALSE?

A) The rate of vaporization increases with increasing surface area.

B) The rate of vaporization increases with decreasing strength of intermolecular forces.

C) The rate of vaporization increases with increasing temperature.

D) Molecules with hydrogen bonding are more volatile than compounds with dipole-dipole forces.

E) None of the above are false.

23) Assign the appropriate labels to the phase diagram shown below.

A) A = liquid, B = solid, C = gas, D = critical point

B) A = gas, B = solid, C = liquid, D = triple point

C) A = gas, B = liquid, C = solid, D = critical point

D) A = solid, B = gas, C = liquid, D = supercritical fluid

E) A = liquid, B = gas, C = solid, D = triple point

24) Choose the statement below that is TRUE.

A) A solution will form between two substances if the solute-solvent interactions are of comparable strength to the solute-solute and solvent-solvent interactions.

B) A solution will form between two substances if the solute-solvent interactions are small enough to be overcome by the solute-solute and solvent-solvent interactions.

C) A solution will form between two substances if the solute-solute interactions are strong enough to overcome the solvent-solvent interactions.

D) A solution will form between two substances only if the solvent-solvent interactions are weak enough to overcome the solute-solvent interactions.

E) None of the above are true.

25) Which of the following statements is TRUE?

A) In general, the solubility of a solid in water decreases with increasing temperature.

B) In general, the solubility of a gas in water decreases with increasing temperature.

C) The solubility of a gas in water usually increases with decreasing pressure.

D) The solubility of an ionic solid in water decreases with increasing temperature.

E) None of the above statements are true.

Answer 1

Answer 20):- The normal boiling point for H₂Se is higher than the normal boiling point for the H₂S because of "larger dispersion forces for H​​​​​​​₂Se".

Option B)- is correct answer.

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Answer 21):- Butane (CH3-CH2-CH2-CH3) has the lowest surface tension...

Option B) is correct one...

Explanation:- More stronger the intermolecular forces, more is the surface tension and vice versa.

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Answer 22):- option d) -"Molecules with hydrogen bonding are more volatile than compounds with dipole-dipole forces" is false statement.

Actually, molecules with hydrogen bonding are less volatile than compounds having dipole-dipole forces , because hydrogen bonds are much stronger than dipole-dipole forces....

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Answer 24):- Option A)- " A solution will form between two substances if the solute-solvent interactions are of comparable strength to the solute-solute and solvent-solvent interactions" is correct one...

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Answer 24):- Option B)- "In general, the solubility of a gas in water decreases with increasing temperature" is correct one..

This is because increase in the temperature increases the kinetic energy of the gas molecules, thus decreases the solubility of gas....