Final answer:
A pure substance is a form of matter with a constant composition and uniform properties, while a mixture combines two or more substances that do not have a uniform composition. White wine and ranch-style salad dressing are mixtures, with wine being homogeneous and the dressing heterogeneous. Mercury is a pure substance (element), and table sugar (sucrose) is a pure substance (compound).
Step-by-step explanation:
Understanding Pure Substances and Mixtures
To identify if a substance is a pure substance or a mixture, one must understand their fundamental differences. A pure substance has a constant composition and uniform properties throughout the sample. This includes both elements, which are composed of a single type of atom, and compounds, which consist of two or more types of atoms chemically bonded together. Conversely, a mixture is a combination of two or more substances that are not chemically bonded and can vary in composition. Mixtures can be either homogeneous, having a uniform composition throughout, or heterogeneous, where the composition is not uniform and the different components can be observed.
Given substances:
- a. White wine - Homogeneous mixture (Solution)
- b. Mercury - Pure substance (Element)
- c. Ranch-style salad dressing - Heterogeneous mixture
- d. Table sugar (sucrose) - Pure substance (Compound)