In a chemical equation, what does the symbol Δ (delta) above the reaction arrow indicate?

• A. The reaction requires heat to proceed.
• B. The reaction is reversible.
• C. The reaction occurs at room temperature.
• D. The reaction produces a precipitate.

Answer: (A)

Verified step by step guidance

1. Understand that in chemical equations, symbols placed above or below the reaction arrow provide additional information about the reaction conditions.
2. Recognize that the symbol \(\Delta\) (delta) placed above the reaction arrow specifically indicates that heat is applied to the reaction mixture.
3. Recall that this means the reaction requires heating to proceed or to increase the reaction rate.
4. Differentiate this from other symbols or conditions, such as a double arrow indicating reversibility, or notes about temperature or precipitate formation written separately.
5. Conclude that the presence of \(\Delta\) above the arrow means the reaction requires heat to proceed.