Which of these definitions BEST describes a solution?
A a mixture in which one substance is evenly distributed within another substance
B a substance that is made up of only one kind of atom
C a combination of three or more different substances that do not chemically combine
D formed when atoms of two or more elements bond in a chemical reaction to make a new substance
The Correct Answer and Explanation is :
The definition that BEST describes a solution is A: a mixture in which one substance is evenly distributed within another substance.
Explanation:
A solution is a homogeneous mixture comprised of two or more substances where one substance, called the solute, is dissolved in another substance, called the solvent. The key feature of a solution is that the solute is uniformly distributed at the molecular level within the solvent, resulting in a consistent composition throughout the mixture. For example, when salt (the solute) is added to water (the solvent), the salt dissolves, and its particles are evenly spread throughout the water. This uniform distribution allows for the same concentration of salt to be present in any sample of the solution, distinguishing solutions from other types of mixtures, such as suspensions or colloids, where the components may not be evenly distributed.
The other definitions provided do not accurately describe a solution:
- B: a substance that is made up of only one kind of atom describes an element, not a solution. Elements are pure substances that cannot be broken down into simpler substances by chemical means.
- C: a combination of three or more different substances that do not chemically combine describes a heterogeneous mixture, such as a salad or a mixture of sand and gravel. In these mixtures, the components can often be physically separated and do not form a uniform composition.
- D: formed when atoms of two or more elements bond in a chemical reaction to make a new substance refers to a compound. Compounds are pure substances formed through chemical bonds between different types of atoms, such as water (H₂O) or carbon dioxide (CO₂).
In summary, option A accurately captures the essence of what a solution is: a homogeneous mixture where the solute is evenly distributed within the solvent.