Ringer's Solution

The ability to successfully make solutions is a basic laboratory skill performed in virtually all biological and chemical experiments. A solution is a homogenous mixture of solute dissolved in bulk liquid known as the solvent. Solutions can be described by their solute concentration, a measure of how much solute is present per unit of solution. In this video, a step-by-step procedure for how to make a water-based, or aqueous, solution for biological applications is presented. The video...

According to Raoult’s law, the partial vapor pressure of a solvent in a solution is equal or identical to the vapor pressure of the pure solvent multiplied by its mole fraction in the solution. However, Raoult's Law is only valid for ideal solutions. For a solution to be ideal, the solvent-solute interaction must be just as strong as a solvent-solvent or solute-solute interaction. This suggests that both the solute and the solvent would use the same amount of energy to escape to the vapor phase...

Source: Laboratory of Dr. Michael Evans — Georgia Institute of Technology A solution is a homogeneous mixture containing some components in small amounts, called solutes, and one component in a large amount, called the solvent. Solid-liquid solutions contain one or more solid solutes dissolved in a liquid solvent. Solutions are ubiquitous in chemistry: they are used to store and handle small amounts of material, carry out chemical reactions, and develop materials with controllable properties.

There is no one solvent that can dissolve every type of solute. Some substances that readily dissolve in a certain solvent might be insoluble in a different solvent. A simple way to predict which substances dissolve in which solvent is the phrase "like dissolves like". This means that polar substances, such as salt and sugar, dissolve in a polar substance like water. In contrast, non-polar substances are more soluble in non-polar solvents such as carbon tetrachloride. This selective solubility...

There are two criteria that favor, but do not guarantee, the spontaneous formation of a solution: A decrease in the internal energy of the system (an exothermic change, as discussed in the previous chapter on thermochemistry) An increased dispersal of matter in the system (which indicates an increase in the entropy of the system, as you will learn about in the later chapter on thermodynamics) In the process of dissolution, an internal energy change often, but not always, occurs as heat is...