Andre adds a spoonful of baking soda to a glass of vinegar. Bubbles begin to appear in the vinegar. The bubbles signal the formation of a(n) __________.
Expanation - The vinegar, an acid, chemically reacts with the baking soda, a base, resulting in the formation of carbon dioxide gas (which causes the bubbles) and water. So, the bubbles signal the formation of a compound, carbon dioxide.