why can a scientist use boiling point or melting point to identify an unknow substance?
It can't usually be used to do that, but it is evidence. One looks at many physical properties, bp, mp, density, crystal type, color, hardness, and so on to identify a substance. Seldom would one rely on just one observation.
what is science
A scientist can use boiling point or melting point to identify an unknown substance because these properties are distinctive for different substances. The boiling point of a substance is the temperature at which it changes from a liquid to a gas, while the melting point is the temperature at which a substance changes from a solid to a liquid.
To identify an unknown substance using boiling point or melting point, a scientist can follow these steps:
1. Obtain a sample of the unknown substance in a pure form. Ensure that it is free from impurities that could affect its boiling or melting point.
2. Prepare equipment for measuring the boiling or melting point, such as a thermometer, heating apparatus, and a suitable container.
3. For the boiling point, set up the equipment to allow the substance to be heated gradually until it starts to boil. Observe the temperature at which boiling occurs and record it.
4. For the melting point, set up the equipment to heat the substance gradually until it begins to melt. Observe the temperature at which the substance transforms from a solid to a liquid and record it.
5. Compare the recorded boiling or melting point value with known values in reference tables or databases. Different substances have different ranges of boiling and melting points, so by matching the observed value with known data, the scientist can make an educated guess about the identity of the unknown substance.
It is important to note that boiling and melting points alone may not be sufficient to definitively identify a substance. However, they can provide important clues that narrow down the possibilities and help guide further analysis or experiments. Other tests like spectroscopy, chromatography, or chemical reactions may be needed for a more conclusive identification of the unknown substance.