5 Questions
What is the condition for a solid to be considered pure based on its melting range?
The melting range is sharp
What happens to the melting point of a substance as molecular weight increases?
The melting point increases
Why does a higher molecular weight molecule have a higher melting point?
Because it requires more energy to break the bond
What indicates that a solid substance is impure?
The melting range is large
What condition describes the melting point of a substance?
The temperature where the solid and liquid states are in equilibrium
Study Notes
Determination of Melting Points
- A solid undergoes a phase transition to a liquid at a specific temperature, where the solid and liquid states coexist in equilibrium.
Factors Affecting Melting Points
-
Purity of the Chemical:
- A sharp melting range indicates a pure solid.
- A large melting range indicates an impure solid, which does not represent the true melting point.
Molecular Weight and Melting Points
- The greater the molecular weight of a molecule, the stronger the bond between molecules.
- Stronger bonds require high energy to break, resulting in higher melting points.
- Examples:
- CRR - CH3: 15°C
- CH3-CH3: 30°C
Learn about the temperature at which a solid turns into a liquid and the factors that affect melting points, including the purity of the chemical.
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