Which one of the following is an endothermic process?

• A. Combustion of methane
• B. Neutralization of hydrochloric acid with sodium hydroxide
• C. Condensation of steam to liquid water
• D. Melting of ice to form liquid water

Answer: (D)

Verified step by step guidance

1. Understand the definition of an endothermic process: it is a process that absorbs heat from the surroundings, causing the system to gain energy.
2. Analyze each given process to determine whether it absorbs or releases heat:
3. - Combustion of methane is an exothermic reaction because it releases heat as methane burns.
4. - Neutralization of hydrochloric acid with sodium hydroxide is also exothermic, releasing heat when an acid and base react.
5. - Condensation of steam to liquid water is exothermic because it releases heat as gas turns into liquid.
6. - Melting of ice to form liquid water is endothermic because it requires heat absorption to change solid ice into liquid water.