Question

2.There are four equal-sized bowls with equal amounts of milk.

Bowl A is covered, and the milk is at room temperature.
Bowl B is uncovered, and the milk is warmer than room temperature.
Bowl C is uncovered, and the milk is cooler than room temperature.
Bowl D is uncovered, and the milk is at room temperature.

Which bowl has the highest vapor pressure?

A.bowl A

B.bowl B

C.bowl C

D.bowl D

3.Cup A and cup B are identical. They contain equal volumes of soup at equal temperatures. Both cups are put in a refrigerator. Cup A has a lid, but cup B does not. Which statement best explains why cup A will cool more slowly than cup B?

A.Water vapor won’t be able to escape from cup A.

B.The most energetic water molecules from cup A will escape more rapidly.

C.No molecules will be able to evaporate at the surface of cup B.

D.No molecules will be able to evaporate at the surface of cup A.

4. Based on the enthalpy changes given for the reactions, which reactions are endothermic? CHOOSE ALL THAT APPLY

2H₂O → 2H₂ + O₂, ΔH = 484 kJ

C + O₂ → CO₂, ΔH = -394 kJ

H₂ + Br₂ → 2HBr, ΔH = -73 kJ

2NH₃ → N₂ + 3H₂, ΔH = 92 kJ

Answer 1

2.B We know that vapor pressure is equilibrium vapor pressure that doesnt depend upon wether container is open or closed it is the property of liquid . It depends only on temperature Hence answer is bowl B

3.D no molecules will be able to evaporate from A. the energetic molecules will remain in the cup hence it remains hot for more time.

4. 2H2O → 2H2 + O2, ΔH = 484 kJ

endothermic reactions the heat is absorbed from the surroundings and the products are at higher energy than the reactants. so change in enthalpy must be positive.