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leojun
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why isn't solution state a true physical state but a pseudo state?
Not all of this is true. For example, if you dissolve sugar in water, the sugar is no longer solid. The solid dissociates into individual molecules, and you can pass the solution through essentially any size filter without separating the solid sugar from the liquid water. The two substances (sugar and water) combine to form one homogeneous phase (in this case, a liquid). It might not be a liquid of a single pure substance, but it's a liquid nonetheless. It conforms to its container, and it can be boiled and frozen just as a liquid can. Of course, it's still possible to recover the sugar as a solid, but you have to add energy (usually in the form of heat) to the system to do this. Just because a solution is made of two different substances doesn't mean you can't identify it as a liquid/solid/gas. It just means you can't identify it as a pure liquid/solid/gas.AndrewAmmerlaa said:A solution is a combination of substances, it's either:
a solid in a liquid,
a liquid in a liquid,
a gas in a liquid
etc.
When a substance is dissolved in a another substance, for instance a solid in a liquid, the substances don't change state, the liquid is still a liquid, and the solid is still a solid. Furthermore a substance can undergo a state change, this is done adding or removing 'heat', dissolving a substance is not a change of state, because no 'heat' is added or removed, therefore solution can't be a state. When you add or remove 'heat', you are actually adding or removing energy, the more energy a substance has, the warmer it is, and the more the molecules in the substance move. So one could define state change as adding or removing energy, when you dissolve a substance, no energy is added or removed, and therefore the state doesn't change
I hope this answered your question
The sugar IS solid, because the individual sugar molecules still have the same amount of energy as they had before dissolving, therefore there is no change of state. yes you can pass the solution through essentially any size filter without separating the solid sugar from the liquid water, but this is because the sugar molecules are separated. Normally sugar molecules group together, and therefore won't pass through the filter, but when dissolved, this structure breaks, and therefore sugar can pass through the filter, the sugar is still solid though.TeethWhitener said:Not all of this is true. For example, if you dissolve sugar in water, the sugar is no longer solid. The solid dissociates into individual molecules, and you can pass the solution through essentially any size filter without separating the solid sugar from the liquid water. The two substances (sugar and water) combine to form one homogeneous phase (in this case, a liquid). It might not be a liquid of a single pure substance, but it's a liquid nonetheless. It conforms to its container, and it can be boiled and frozen just as a liquid can. Of course, it's still possible to recover the sugar as a solid, but you have to add energy (usually in the form of heat) to the system to do this. Just because a solution is made of two different substances doesn't mean you can't identify it as a liquid/solid/gas. It just means you can't identify it as a pure liquid/solid/gas.
True, but this is a chemical reaction, not a change of state. It all comes down to how one defines dissolving, I would define this as a reaction, not as a dissolution, because the substances before the reaction aren't the same as after the reaction, when dissolving the substances before the reaction are the same as after the reaction. After dissolving sugar, the solution still contains sugar molecules. Salts is a different story, it falls apart in ions when added to water, and therefore is not the same as before.TeethWhitener said:In addition, dissolving substances does cause an exchange of heat. Compare the dissolution of lithium chloride, sodium chloride, and potassium chloride in water. KCl causes the water to cool significantly while LiCl causes the water to heat significantly (NaCl doesn't cause much of a temperature change). Here's a video of NH4Cl dissolving in water endothermically:
AndrewAmmerlaa said:The sugar IS solid, because the individual sugar molecules still have the same amount of energy as they had before dissolving, therefore there is no change of state.
No, it's not. There is a heat of solution associated with any solvation process, regardless of whether ionic dissociation occurs or not. Look at Ygggdrasil's post about lattice energy. For another clear example (one which very clearly involves no chemical change), consider the dissolution of eicosane in toluene. The toluene gets quite a bit colder in this case. (Interestingly, in this case, it's not so much an enthalpy contribution as it is an entropy contribution--from an increase in internal degrees of freedom of the alkane--which causes the cooling.) But regardless, there is always energy exchange associated with rearranging molecules to form stable solvation shells.AndrewAmmerlaa said:True, but this is a chemical reaction, not a change of state.
I never heard of this. How do you define a state an in which context?leojun said:why isn't solution state a true physical state but a pseudo state?
Solution state is not considered a true physical state because it is a mixture of two or more substances, rather than a pure substance. This means that the properties of a solution, such as its boiling point or density, are not fixed and can vary depending on the composition of the solution.
A physical state refers to the form or phase of matter, such as solid, liquid, or gas. A solution state, on the other hand, refers to a mixture of substances in which one substance (the solute) is dissolved in another substance (the solvent). While a physical state is a distinct form of matter, a solution state is a combination of different substances.
No, a solution state cannot be changed into a physical state. This is because a solution is a mixture of substances, and changing its physical state would require separating the individual components of the solution. This can only be achieved through chemical reactions or physical processes such as evaporation or distillation.
Solution state is important in chemistry because many chemical reactions occur in solution. The solubility of substances in different solvents can also provide valuable information about the nature of the substances and their chemical properties. Additionally, many industrial processes rely on solutions for the production of various products.
No, solution state is not considered a state of matter. Instead, it is a type of mixture that exists in a specific physical state, such as liquid or gas. While the individual components of a solution may have distinct states of matter, the solution itself is not considered a state of matter.