Question

question 3 (3 points)
indicate which molecule, a or b, has the strongest attractive forces
1 a. melting point of 25 °c b. melting point of 75 °c
2 a. boiling point of 25 °c b. boiling point of 75 °c
3 a. vapor pressure of 20 torr b. vapor pressure of 5 torr
4 a. high surface tension b. low surface tension
question 4 (3 points)
indicate which molecule, a or b, has the strongest attractive forces
1 a. heat of vaporization of 10. cal/g°c b. heat of vaporization of 100. cal/g°c
2 a. molecule with dipolar attractions b. molecule with hydrogen bonding
3 a. molecule with londons b. molecule with dipolar attractions
4 a. an ionic compound b. molecule with hydrogen bonding

Explanation:

• Question 3:
• 1: Higher melting point means stronger attractive forces. Since \(75^{\circ}C>25^{\circ}C\), molecule B has stronger attractive forces.
• 2: Higher boiling point implies stronger attractive forces. As \(75^{\circ}C > 25^{\circ}C\), molecule B has stronger attractive forces.
• 3: Lower vapor pressure indicates stronger attractive forces. Given \(5\ torr<20\ torr\), molecule B has stronger attractive forces.
• 4: Higher surface tension is associated with stronger attractive forces. So, molecule A has stronger attractive forces.
• Question 4:
• 1: Higher heat of vaporization means more energy is needed to overcome attractive forces. Since \(100\ cal/g^{\circ}C>10\ cal/g^{\circ}C\), molecule B has stronger attractive forces.
• 2: Hydrogen bonding (\(B\)) is stronger than dipolar attractions (\(A\)).
• 3: Dipolar attractions (\(B\)) are stronger than London's forces (\(A\)).
• 4: Ionic compounds (\(A\)) have stronger attractive forces (ionic bonds) than hydrogen - bonded molecules (\(B\)).

Answer:

Question 3:

1. B
2. B
3. B
4. A

Question 4:

1. B
2. B
3. B
4. A