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Multiple Choice
Which of the following samples is a pure substance?
A
zinc oxide
B
soil
C
sugar dissolved in water
D
pond water
Verified step by step guidance
1
Understand the definition of a pure substance: a pure substance has a fixed composition and distinct chemical properties, consisting of only one type of particle (element or compound).
Analyze each option to determine if it meets the criteria of a pure substance:
- Soil is a mixture of various minerals, organic matter, and other components, so it is not a pure substance.
- Sugar dissolved in water forms a homogeneous mixture (solution), not a pure substance, because it contains more than one component.
- Pond water contains various dissolved substances and organisms, making it a mixture rather than a pure substance.
- Zinc oxide is a chemical compound with a fixed composition and uniform properties, qualifying it as a pure substance.