Chemical leavening agents are substances used in baking to produce gas, which helps dough or batter rise. Common examples include baking soda and baking powder. When these agents react with moisture and heat, they release carbon dioxide gas, creating bubbles that expand and lighten the texture of baked goods. Baking soda is a pure form of sodium bicarbonate, while baking powder contains sodium bicarbonate along with an acid and a moisture-absorbing agent. This combination allows baking powder to work without needing additional acidic ingredients. Both agents are essential for achieving the desired fluffiness in items like cakes, cookies, and breads.