Question

Urea (NH2CONH2) dissolves readily in water; i.e., this is a spontaneous process. The beaker containing the dissolved compound is cold to the touch. Which of the following statements is correct?

a) The dissolution of urea is endothermic.
b) The dissolution of urea is exothermic.
c) The dissolution of urea is at equilibrium.
d) The dissolution of urea is an isothermal process.

Answer 1

The dissolution of urea in water, which causes the solution to feel cold, is an endothermic process because it absorbs heat from the surroundings. Therefore, correct option is a.

Step-by-step explanation:

The question asks about the dissolution process of urea (NH2CONH2). When urea dissolves in water and the solution becomes cold to the touch, this indicates that the process is absorbing heat from the surroundings, which is characteristic of an endothermic process.

Hence, the correct answer is a) The dissolution of urea is endothermic. This is supported by knowledge that in spontaneous endothermic processes, such as ice melting above 0°C or the dissolution of certain salts like ammonium nitrate (NH4NO3), the system absorbs heat (ΔH > 0) from the environment, even though these processes are spontaneous due to an increase in entropy (ΔS).