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Multiple Choice
Which of the following is a characteristic of a pure substance?
A
It is always a mixture of two or more elements.
B
Its properties vary depending on the sample taken.
C
It can be separated into different components by physical means.
D
It has a fixed and definite composition.
Verified step by step guidance
1
Understand the definition of a pure substance: A pure substance has a fixed and definite composition, meaning its chemical makeup does not vary from sample to sample.
Recognize that a pure substance is not a mixture; mixtures consist of two or more substances physically combined, whereas pure substances are chemically uniform.
Recall that the properties of a pure substance are consistent and do not change depending on the sample, unlike mixtures whose properties can vary.
Know that pure substances cannot be separated into different components by physical means because they consist of only one type of particle or compound.
Conclude that the characteristic 'It has a fixed and definite composition' correctly describes a pure substance.