CH Chapter 7 - Solutions - Chemistry
There is a linear relationship between flow rate and the inverse of the solvent of solutes affects the viscosity, density, and diffusivity of the feed solution. Apr 20, dayline.info -you-had-amolar-solution How does water's polarity influence its properties as a solvent? Water polarity . What is the relationship between solutions, solutes and solvents. The solvent.
Solubility depends on the properties of the solvent. Definition of Solute A substance dissolved in a solution is called as the solute. A solute can be solid, liquid or gas, though mostly it is a solid compound. Salt in seawater, sugar in water, and oxygen in the air are the few typical example of the solutes.
The solute dissolves in the solvent only when the attractive forces between the two is stronger enough, which can overcome molecular forces holding the particles, i.
Although the solute holds the minor amount in the solution, as compared to the solvent. But there is the condition in the solution called as saturation, in which the solvent is not able to dissolve any more solute.
What is the relationship among solutions, solutes, and solvents?
Example of a solute and solvent can be explained by considering a cup of tea. Milk powder and sugar are dissolved in hot water. Here hot water is the solvent and milk powder and sugar are solutes. Characteristics of the Solute Solute have higher boiling points than solvent.
These can be solid, liquid or gas.Distribution Law / Partition Law & Coefficient
By increasing the surface area of the particles of the solute, the solubility will increase. The solid particles are broken into smaller pieces. In case of gaseous solutes, the solubility is affected by the pressure, besides the volume and temperature.
Definition of Solvent The solute is dissolved in the solvent.
CH150: Preparatory Chemistry
It can also be defined as the substance in which different substances or compounds dissolved to become a solution. Note that when ionic compounds dissolve in a solvent they break apart into free floating ions in solution. This enables the compound to interact with the solvent. In the case of water dissolving sodium chloride, the sodium ion is attracted to the partial negative charge of the oxygen atom in the water molecule, whereas the chloride ion is attracted to the partial positive hydrogen atoms.
The Process of Dissolving. When an ionic salt, such as sodium chloride, shown in Acomes into contact with water, the water molecules dissociate the ion molecules of the sodium chloride into their ionic state, shown as a molecular model in B the solid crystalline lattice of sodium chloride, and C the sodium chloride dissolved in the water solvent. Photo of sodium chloride provided by Chris Many ionic compounds are soluble in water, however, not all ionic compounds are soluble. Ionic compounds that are soluble in water exist in their ionic state within the solution.
You will notice in Figure 7. For ionic compounds that are not soluble in water, the ions are so strongly attracted to one another that they cannot be broken apart by the partial charges of the water molecules.
The following table can be used to help you predict which ionic compounds will be soluble in water. Because of this property, soluble ionic compounds are referred to as electrolytes.
Many ionic compounds dissociate completely and are therefore called strong electrolytes. Sodium chloride is an example of a strong electrolyte. Some compounds dissolve but dissociate only partially, and solutions of such solutes may conduct electricity only weakly. These solutes are called weak electrolytes. Solutes that dissolve into individual neutral molecules without dissociation do not impart additional electrical conductivity to their solutions and are called nonelectrolytes.
Polar covalent compounds, such as table sugar C12H22O11are good examples of nonelectrolytes. The term electrolyte is used in medicine to mean any of the important ions that are dissolved in aqueous solution in the body.
Sports drinks such as Gatoraid have combinations of these key electrolytes, to help replenish electrolyte loss following a hard workout. Similarly, solutions can also be made by mixing two compatible liquids together.
- Difference Between Solute and Solvent
- What is the relationship among solutions,solutes and solvents?
- What is the relationship among solutions, solutes, and solvents?
The liquid in the lower concentration is termed the solute, and the one in higher concentration the solvent. When two similar solutions are placed together and are able to mix into a solution, they are said to be miscible.
Liquids that do not share similar characteristics and cannot mix together, on the other hand, are termed immiscible. For example, the oils found in olive oil, such as oleic acid C18H34O2 have mainly nonpolar covalent bonds which do not have intermolecular forces that are strong enough to break the hydrogen bonding between the water molecules.
Thus, water and oil do not mix and are said to be immiscible. Other factor such as temperature and pressure also affects the solubility of a solvent. Thus, in specifying solubility, one should also be aware of these other factors.
Although the solubility of a solid generally increases with increasing temperature, there is no simple relationship between the structure of a substance and the temperature dependence of its solubility. Many compounds such as glucose and CH3CO2Na exhibit a dramatic increase in solubility with increasing temperature.
Solubility may increase or decrease with temperature; the magnitude of this temperature dependence varies widely among compounds.
The variation of solubility with temperature has been measured for a wide range of compounds, and the results are published in many standard reference books. Chemists are often able to use this information to separate the components of a mixture by fractional crystallizationthe separation of compounds on the basis of their solubilities in a given solvent.
According to the temperature curves in Figure 7. The crystals can then be separated by filtration. Fractional crystallization is a common technique for purifying compounds as diverse as those shown in Figure 7. For the technique to work properly, the compound of interest must be more soluble at high temperature than at low temperature, so that lowering the temperature causes it to crystallize out of solution.
In addition, the impurities must be more soluble than the compound of interest as was KBr in this example and preferably present in relatively small amounts. The solubility of gases in liquids is much more predictable. The solubility of gases in liquids decreases with increasing temperature, as shown in Figure 7. Attractive intermolecular interactions in the gas phase are essentially zero for most substances, because the molecules are so far apart when in the gaseous form.
When a gas dissolves, it does so because its molecules interact with solvent molecules. Heat is released when these new attractive forces form. Thus, if external heat is added to the system, it overcomes the attractive forces between the gas and the solvent molecules and decreases the solubility of the gas. But it results in a change in the temperature at which the solution freezes or melts. To understand why, we have to look carefully at the line that separates the solid and liquid regions in the phase diagram.
This line is almost vertical because the melting point of a substance is not very sensitive to pressure. Adding a solute to a solvent doesn't change the way the melting point depends on pressure. The line that separates the solid and liquid regions of the solution is therefore parallel to the line that serves the same function for the pure solvent.
This line must pass through the triple point for the solution, however. The decrease in the triple point that occurs when a solute is dissolved in a solvent therefore decreases the melting point of the solution.
The figure above shows how the change in vapor pressure that occurs when a solute dissolves in a solvent leads to changes in the melting point and the boiling point of the solvent as well.
Because the change in vapor pressure is a colligative property, which depends only on the relative number of solute and solvent particles, the changes in the boiling point and the melting point of the solvent are also colligative properties.
The best way to demonstrate the importance of colligative properties is to examine the consequences of Raoult's law. Raoult found that the vapor pressure of the solvent escaping from a solution is proportional to the mole fraction of the solvent. Only the change in the vapor pressure that occurs when a solute is added to the solvent can be included among the colligative properties of a solution. Because pressure is a state function, the change in the vapor pressure of the solvent that occurs when a solute is added to the solvent can be defined as the difference between the vapor pressure of the pure solvent and the vapor pressure of the solvent escaping from the solution.