Nicole has 2 glasses on the counter: one of water and one of sugar-water. She is baking a cake and needs to use the sugar-water for the glaze. Both glasses look identical, but one contains a mixture and the other contains a compound. Is sugar-water a mixture or a compound? Define mixtures and compounds, and explain how, without tasting it, Nicole can test to make sure she is using the sugar-water in the glaze.