Solutions and Mixtures

Mixture

Two or more substances mixed together. They can be a solid, liquid or gas

Heterogeneous Mixtures

Mixtures where different parts of the mixtures can be seen with the naked eye. Concentrations are inconsistent.

Homogenous Mixtures

Mixtures where any point of the mixture looks consistent to the naked eye.  Cannot distinguish components.

Solutions

Homogenous mixtures. They can be solid, liquid or gases.

What is an example of a solid solution?

Metal Alloy. Color, malleability, conductivity, and hardness seem uniform.

What is an example of a liquid solution?

Salt water. Sodium Chloride is dissolved in water and appearance, reactions, conductivity seem to be uniform.

Solute

Thing that is getting dissolved. Sodium Chloride in salt water.

Solvent

Things that are getting dissolved in. Water is the most common solvent

Aqueous solution(aq)

Where water is the solvent.

What is an example of a gas solution?

Air. Macroscopic properties of nitrogen, oxygen and carbon dioxide all seem to be uniform.

Molarity

Method to measure solute concentration in a solution. Defined by # of moles of solute/liters of solution.

Concentration

Amount of solute dissolved in a given volume. It indicates how “strong” or “weak” the solution is.

What is the molarity of a 250 milliliters of solution composed of H20 and 35.5grams of sodium sulfate?

1.00Molar(moles/liter)

Dilution

Reducing the concentration of a solute in a solution by adding more solvent(diluting).

Dilution Calculations

1. # of moles of solute(final diluted solution) = Liters of solution x concentration(molarity), 2. # of moles = Concentration x volume(starting, more concentrated solution), 3. Volume of  diluted solution -  Volume of concentrated solution = Volume of water that must be added.

What is the volume of water that must be added to prepare 2.0 L of 3.0 M KOH from a stock solution that has a concentration of 8.0 mol/L?

.75L