Acids and Bases :Acids and Bases Investigation Two


Journal :Journal What is dilution?


What is concentration? :What is concentration? In chemistry, concentration is the measure of how much of a given substance there is mixed with another substance. The more of a given substance the higher the concentration.


Recall :Recall Acids and bases make up two important groups of compounds. Compounds are groups of two or more elements that are bonded together.


major differences among Acids and bases :major differences among Acids and bases One of the major differences among these two compounds has to do with the ions (charged particles) that they contain. An acid contains more hydrogen (H+) ions than hydroxide (OH–) ions A base contains more hydroxide (OH–) ions than hydrogen (H+) ions


Recall :Recall An acid is a substance from which a proton can be removed. A base is a substance that can remove a proton from an acid. Remember: proton, hydrogen ion and H+ all mean the same thing


Slide 7:A homogeneous mixture is where two substances mix together so that they look and feel like the same thing.


Solution, Solvent and Solute :Solution, Solvent and Solute A solution is a homogeneous mixture of ions or molecules of two or more substances.


A solution has two parts: :A solution has two parts: Solvent is the component that is in the largest quantity Solute is the component that is dissolved in the solvent. The coffee is the solvent, the sugar is the solute, and the sweeten coffee would be the solution.


Dilution Methods :Dilution Methods


When making a dilution always add to the water. :When making a dilution always add to the water. Timberlake, Chemistry 7th Edition, page 344 initial solution remove sample diluted solution moles of solute Diluting a solution


Serial dilution :Serial dilution The solutions to the right were made by serially diluting an extract made from soaking two cigarette filters in 20ml of alcohol. As the stock solution is diluted it becomes lighter in color.How was this done?


The first step in making a serial dilution :The first step in making a serial dilution Take a known volume of stock and place it into a known volume of distilled water. This produces of dilute solution. The dilute solution has 1ml of extract /10ml.


Successive Serial Dilutions :Successive Serial Dilutions The technique used to make a single dilution is repeated sequentially using a more and more dilute solution as the "stock" solution.


Slide 15:At each step 1ml of the previous dilution is added to 9ml of distilled water. Each step results in a 10 fold change in the concentration from the previous concentration.


Serial dilution :Serial dilution Remember: Each time we made a new solution in our example the concentration was 10 times less than the previous. This is because we added 1 ml of the previous solution to 9ml of water for a total of 10 ml. Changes the concentration of H+ ions are made by diluting a solution by adding more solvent (the component that is in the largest quantity).