Question

q.9. which of the following is a heterogeneous mixture?
a) air b) steel
c) soil d) vinegar
q.10. which of the following is a homogeneous mixture?
a) ice cubes in soda b) vinegar
c) sandy water d) silver
q.11. what is another term for homogeneous mixture?
a) elements b) compounds
c) pure substances d) solutions
q.12. air is a(an)___________ of many gases that are odorless and colorless.
a) mixture b) element
c) compound d) atom

Explanation:

• Q.9: A heterogeneous mixture has visibly different substances or phases. Soil contains various components like minerals, organic matter, air, and water that are not uniformly distributed. Air is a homogeneous mixture of gases. Steel is an alloy (a homogeneous mixture of metals). Vinegar is a solution (homogeneous mixture of acetic acid and water).
• Q.10: A homogeneous mixture has a uniform composition throughout. Vinegar is a solution (uniform composition). Ice cubes in soda (heterogeneous as there are distinct phases - solid ice and liquid soda). Sandy water (heterogeneous as sand and water are not uniformly mixed). Silver is an element (not a mixture).
• Q.11: A homogeneous mixture is also called a solution. Elements are pure substances with only one type of atom. Compounds are pure substances formed by chemical combination of elements. Pure substances have a definite composition (either elements or compounds).
• Q.12: Air is made up of multiple gases (like nitrogen, oxygen, carbon - dioxide etc.) mixed together. An element is a pure substance (e.g., oxygen as an element is \(O_2\), but air is a combination). A compound is a pure substance formed by chemical bonds (e.g., \(CO_2\)). An atom is the basic unit of an element.

Answer:

• Q.9: C. Soil
• Q.10: B. Vinegar
• Q.11: D. solutions
• Q.12: A. mixture