Question

how do you know there was a chemical reaction? check all indicators below. a solid precipitate formed. the color changed. a gas was produced. the reaction absorbed or released heat.

Explanation:

In chemistry, indicators of a chemical reaction include the formation of a precipitate (solid from a solution mixture), color change (due to new substance formation), gas production (effervescence, new gaseous substance), and energy change (heat absorbed - endothermic, or released - exothermic). All these options represent valid signs of a chemical reaction.

Answer:

A. A solid precipitate formed.
B. The color changed.
C. A gas was produced.
D. The reaction absorbed or released heat.