We are given with some of the processes. Choose the process(es) which is/are endothermic (ΔH > 0) i.e. heat is absorbed during the process.

Understand the Problem

The question is asking to identify which of the given chemical processes are endothermic, meaning they absorb heat (ΔH > 0). This involves assessing each provided reaction to determine if heat is absorbed.

More Information

In the given processes, C involves adding more electrons to neutral atoms, which often requires energy. Similarly, D involves converting Na⁺ to Na, a process that typically requires energy input due to the electrostatic attraction that must be overcome.

Tips

A common mistake is to confuse exothermic and endothermic processes. Remember that endothermic processes absorb heat, resulting in a positive ΔH.

Sources

• Endothermic vs. exothermic reactions (article) - Khan Academy - khanacademy.org
• Endothermic and exothermic processes (video) - Khan Academy - khanacademy.org