Question

answer the following questions below.
1. Which liquid sample is a pure substance?
Table 1: Boiling point of two liquid samples
Samples Temperature | Observation while heating
Liquid A
Liquid B
2. Which solid sample is a pure substance?
Scenario 1: Melting point of two solid samples
Samples Appearance Observation while melting
Solid A
Solid B
During boiling, the temperature of a substance changes at the start then it
becomes the same and constant. During melting, a substance melts completely/
smoothly within a short time.​

Answer 1

•Melting point is often used to determine whether a substance is pure or impure.
•Pure substance has constant properties throughout. They display a sharp melting point and a sharp boiling point.
•An impure substance is a mixture composed mostly of one pure substance but with trace amounts of other substances which are called impurities as a whole.
•Sharp melting point and boiling point indicates that the substance is pure, hence solid A and liquid A are pure substance.
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