Mixtures vs. Substances
Mixtures versus substances is a foundational chemistry concept: a mixture combines two or more substances physically without chemical bonding, while a substance has a uniform composition with unique properties. In Amplify Science (California) Grade 7, Chapter 1: Properties and Atoms, students learn to distinguish between mixtures like soil and air, and pure substances like rust (iron oxide), which forms through a chemical reaction.
Key Concepts
Most things in the world are mixtures , combinations of two or more substances that are physically blended but not chemically bonded. Soil, air, and saltwater are mixtures.
In a mixture, the individual substances keep their own properties. However, in the Westfield case, the rust is not a mixture of iron and dirt; it behaves as a single, new substance with its own unique properties.
Common Questions
What is the difference between a mixture and a substance?
A mixture is a physical blend of two or more substances that each keep their own properties, like soil or saltwater. A substance is a material with a uniform composition and its own unique properties, like iron or water.
Is rust a mixture or a substance?
Rust (iron oxide) is a substance, not a mixture. It forms through a chemical reaction between iron and oxygen, producing a new material with its own unique properties different from either iron or oxygen alone.
Why do substances have unique properties?
Substances have fixed compositions made of one type of atom or molecule, giving them consistent, predictable properties. Mixtures vary in composition and the components retain their individual properties.
Where are mixtures and substances covered in Amplify Science Grade 7?
Mixtures vs. substances is covered in Amplify Science (California) Grade 7, Chapter 1: Properties and Atoms.