替える

1. Origins, structure, and basic meaning

• Structure: 替える(かえる) means replacing something in use with something else.
• Basic usage: It describes changing a dead battery or replacing the curtains in a room.

2. Common pitfalls and similar expressions

• The item and its replacement
  • In 電池を新しいものに替える, を marks the item replaced and に marks what will be used instead.
• The distinction from changing a state
  • 気分を変える means changing one's mood; カーテンを替える means replacing the curtains.