What is a Solution
Solutions are homogeneous mixtures where one substance is dissolved in another.
Solute: The substance that dissolves.
Solvent: The substance in which the solute is dissolved.
Ex. In a saltwater solution, the solute, salt, is dissolved in the solvent, water.
Water is one of the most important solvents in chemistry.
Typically solutions consist of a solid solute and liquid solvent, but you can also have ↴
– Gas (solute), liquid (solvent) (Ex. Soda)
– Gas (solute), gas (solvent)
– Liquid (solute), liquid (solvent) (Ex. Antifreeze)
– And as mentioned, solid (solute), liquid (solvent) (Ex. Salt water)
Some other properties are ↴
– You cannot separate the solute and solvent through filtration
– Solute particles are not visible to the naked eye
Concentration
Concentration describes how much solute exists in a given amount of solvent/solution. Here are some common expressions ↴
Molarity: moles of solute per liter of solution (mol/L), represented by “M.” This is the most common one, it is used a lot in chemistry.
Molality: moles of solute per kilogram of solvent (mol/kg), represented by “m.”
Mole-fraction: (moles of substance A/total moles). There are no units; it is just a ratio.
Mass percent: (mass of substance A/total mass) x 100%. There are no units; it is just a percentage.
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