A student shared with the class the four following models and said that ALL of them were mixtures. Do you agree with this student's statement? Explain why or why not.
- Salt water: This is a mixture because it consists of two or more substances (salt and water) that are physically combined and can be separated through physical means such as evaporation or filtration.
- Brass: This is also a mixture because it is composed of two or more metals (copper and zinc) that are physically combined and can be separated through physical means such as melting and then solidifying the metals separately.
- Air: Air is a mixture because it is composed of various gases (such as nitrogen, oxygen, and carbon dioxide) that are physically combined and can be separated through physical means such as fractional distillation.
- Sugar: Sugar is a pure substance because it is made up of only one type of molecule (sucrose) and cannot be separated into simpler substances through physical means. Therefore, it is not a mixture.