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What happens
When a substance is pure, its melting and boiling points obviously stay the same as there are no changes to the actual substance. When a substance is impure, it causes its melting and boiling points to change and lie within a certain range. Whether the melting point increases or decreases depends on the bonding of the substance and the impurities, which gets quite complicated. For example, pure water has a boiling point of 100 degrees Celsius while water with impurities with have a boiling point in range of 100 degrees. Many factors make this so.
Why does it happen
One is the basic fact that there are more particles so the heat energy takes longer to travel through the solution (this is, if you consider particle theory, kinetic energy.)
Another factor has to do with bonding and some other chemical properties. If you want to read about this other factor, read the paragraph below. Otherwise, just skip it.
To continue with the simple example of a salt and water solution salt, I will talk about intermolecular forces. These are forces between molecules in the solution (the forces between the sodium chloride molecules and the water molecules). Sodium and chlorine are bonded with ionic bonds in sodium chloride. In case you don't know what ionic bonding is, read the paragraph below, otherwise, skip the paragraph.
Ionic bonding is a type of bonding between mostly metals and non - metals and you need to have a solid grasp of atomic structure to be able to comprehend this. Usually, a metal will have one electron on its outer shell. A non-metal, however, has an outer shell that is missing one electron. Both atoms 'want' to have a full outer shell (it actually has to do with electrostatic forces but this is a nice way to think of it). In order for both atoms, the metal one and the non-metal one to have a full outer shell, the metal atom loses its one electron on its outer shell and gives it to the non-metal, which now gains one electron on its outer shell to give it a full outer shell. Because the metal has lost an electron, it has now lost one unit of charge and has become positive, as it now has more protons than electrons, and the non-metal has gained one electron to become negatively charged. Any atom that has an imbalance of protons and electrons and its electric charge is therefore not balanced, is called an ion and this is called ionic bonding. The water molecule is covalently bonded. It has a hydrogen bond and this is because of electrostatic forces; oxygen has a chemical property called electronegativity, which sounds hard to understand but actually isn't. All it means is that oxygen has a tendency to attract electrons. Hydrogen atoms are the opposite; they have the property electro positivity, meaning they do the opposite of oxygen atoms. This means that they can form a perfect hydrogen bond. Boiling actually works by particles escaping the solution by escaping from the surface, which means that the particles at the bottom need more energy. When salt is added, the electronegative oxygen atoms go to the Na+ atoms and the oxygen atoms are attracted to them (intermolecular forces). This means that more heat is required to make them leave and get enough energy so the overall boiling point of the solution will increase.
There are some other factors that you have to consider but they require a really strong grasp of chemistry to understand.
What else can I help you with?
What effect has impurities on melting and boiling points of a pure substance?
Impurities can lower the melting point and raise the boiling point of a pure substance. This occurs because impurities disrupt the crystal lattice structure of the substance, making it harder for the molecules to align and transition between solid and liquid states. The presence of impurities can also alter the intermolecular forces between molecules, affecting the energy required for melting and boiling.
How does IMF affect the boiling point or melting point of a substance?
IMF (intermolecular forces) affect the boiling and melting points of a substance by influencing the strength of the bonds between molecules. Stronger IMFs lead to higher boiling and melting points because more energy is required to overcome these forces. Weaker IMFs result in lower boiling and melting points as less energy is needed to break the intermolecular interactions.
Why do impurities lower the boiling point of a pure substance?
The presence of the impurities will cause the boiling points to rise (also the melting points to fall). When you add the impurities, the substance doesn't remain pure affecting the boiling point to increase because now, more energy is required to boil the liquid with impurities. The melting points fall because impure substances require less energy to separate the particles.
Do all liquids have the same boiling and melting point?
No, different liquids have different boiling and melting points depending on their chemical composition. The boiling point is the temperature at which a liquid turns into a gas, while the melting point is the temperature at which a solid turns into a liquid. Each liquid has its own unique set of physical properties that determine its specific boiling and melting points.
Effect of impurities on melting point and melting point?
According to RAOULT, when two different metals of different melting points are melted or alloyed there melting points considerably change. So,according to the percentage of impurities, the melting points either increase or decrease.
Could you tell me 3 examples from everyday life which show the affect of pressure and impurities on the melting and boiling points?
hey i really need help, can u answer the Question
What effect has impurities on melting and boiling points of a pure substance?
Impurities can lower the melting point and raise the boiling point of a pure substance. This occurs because impurities disrupt the crystal lattice structure of the substance, making it harder for the molecules to align and transition between solid and liquid states. The presence of impurities can also alter the intermolecular forces between molecules, affecting the energy required for melting and boiling.
How does IMF affect the boiling point or melting point of a substance?
IMF (intermolecular forces) affect the boiling and melting points of a substance by influencing the strength of the bonds between molecules. Stronger IMFs lead to higher boiling and melting points because more energy is required to overcome these forces. Weaker IMFs result in lower boiling and melting points as less energy is needed to break the intermolecular interactions.
How do you identify solids at melting or boiling points?
Melting and boiling points are different for each compound or element.
Do elements compounds and mixtures have fix melting and boiling point?
Elements have fixed melting and boiling points, while compounds have varying melting and boiling points depending on their composition. Mixtures do not have fixed melting and boiling points, as they are composed of multiple substances which each have their own individual melting and boiling points.
Why do impurities lower the boiling point of a pure substance?
The presence of the impurities will cause the boiling points to rise (also the melting points to fall). When you add the impurities, the substance doesn't remain pure affecting the boiling point to increase because now, more energy is required to boil the liquid with impurities. The melting points fall because impure substances require less energy to separate the particles.
Do all liquids have the same boiling and melting point?
No, different liquids have different boiling and melting points depending on their chemical composition. The boiling point is the temperature at which a liquid turns into a gas, while the melting point is the temperature at which a solid turns into a liquid. Each liquid has its own unique set of physical properties that determine its specific boiling and melting points.
What is melting points and the boiling points?
Melting point: the temperature at which a solid become a liquid. Boiling point: the temperature at which a liquid become a gas.
What are neon's boiling and melting points?
Boiling Point 27.07 K Melting Point 24.56 K
What have high melting and boiling points?
metals
Effect of impurities on melting point and melting point?
According to RAOULT, when two different metals of different melting points are melted or alloyed there melting points considerably change. So,according to the percentage of impurities, the melting points either increase or decrease.
What is goals boiling and melting point?
Melting and boiling points are important characteristics of materials: they are needed in industry and in laboratory.
