Soda water is a mixture of carbon dioxide gas and water. Typically, more bubbles of carbon dioxide gas form near the surface and sides of a glass of soda water than in the middle. Soda water is

A homogeneous mixture has the same composition throughout. In soda water, carbon dioxide bubbles are concentrated near the surface and sides rather than being evenly distributed, so the mixture is not uniform throughout. Therefore, soda water is heterogeneous.

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