Question

which of the following statements about mixtures is false?
select all that apply
a mixtures can be separated using physical properties
b they are all mixed uniformly and have an even composition throughout
c the components keep their physical properties
d substances must combine in specific proportions

Explanation:

• Statement a: Mixtures can be separated using physical properties (e.g., filtration for solids - liquid mixtures based on particle size). So, this statement is True.
• Statement b: Mixtures can be heterogeneous (not uniformly mixed, e.g., sand - water mixture) or homogeneous (uniformly mixed, e.g., salt - water solution). So, the statement “they are all mixed uniformly and have an even composition throughout” is False.
• Statement c: In a mixture, components retain their physical properties. For example, in an iron - sulfur mixture, iron is magnetic and sulfur is not. So, this statement is True.
• Statement d: In a mixture, substances can combine in any proportion. In a compound, substances combine in specific proportions. So, the statement “Substances must combine in specific proportions” is False.

Answer:

B. they are all mixed uniformly and have an even composition throughout, D. Substances must combine in specific proportions