What is/are true for substance and mixture?
I. Pure substance melts completely.
II. Pure substance has a varying boiling point.
III. Mixture does not melt completely.
IV. Mixture has a fixed boiling point.
A. I and II only
B. I and III only
C. II and IV only
D. I and IV only
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Answer:
B. I and III only
Explanation:
Because pure substances is a sample of matter with both definite and constant composition and distinct chemical properties. Since it has a distinct chemical properties, it doesn't have a varying boiling point and melts completely when heated. Unlike mixture, which are combination of pure substances, doesn't melt completely and has a varying boiling point.