Here's the classification of each substance as either a homogeneous mixture or a heterogeneous mixture:
| Substance | Type of Matter | |---------------------------|-------------------------| | Saltwater | Homogeneous mixture | | Iron | Element (not a mixture) | | Salad | Heterogeneous mixture | | Carbon Dioxide | Compound (not a mixture) | | Air | Homogeneous mixture | | Oil and Water Mixture | Heterogeneous mixture | | Lemonade | Homogeneous mixture | | Oxygen | Element (not a mixture) | | Salt | Compound (not a mixture) | | Spaghetti | Heterogeneous mixture |
Please note that elements and compounds are not classified as mixtures, but I included that information for clarity.