Question

take some water in a beaker at 10°c and let it warm to room temperature, 25°c, and take some water at 90°c and let it cool to room temperature, 25°c. the enthalpy of the two samples of water will be identical after they both reach room temperature. however, the change in enthalpy for the two water samples in order for them to go from their starting temperatures to the final temperature, δh, will be different. what will the two changes in enthalpy be? δh is positive for warming from 10°c: δh is positive for cooling from 90°c. δh is negative for warming from 10°c: δh is positive for cooling from 90°c. δh is positive for warming from 10°c: δh is negative for cooling from 90°c. δh is negative for warming from 10°c: δh is negative for cooling from 90°c. dont test me yet, i am trying to gain an understanding before attempting to answer this question.

Explanation:

Step1: Recall the concept of enthalpy change ($\Delta H$)

Enthalpy change ($\Delta H$) is positive when heat is absorbed (endothermic process) and negative when heat is released (exothermic process).

Step2: Analyze the warming process

When water warms from \(10^{\circ}C\) to \(25^{\circ}C\), it absorbs heat. So, \(\Delta H\) is positive for warming.

Step3: Analyze the cooling process

When water cools from \(90^{\circ}C\) to \(25^{\circ}C\), it releases heat. So, \(\Delta H\) is negative for cooling.

Answer:

\(\Delta H\) is positive for warming from \(10^{\circ}C\) and \(\Delta H\) is negative for cooling from \(90^{\circ}C\)