Today in Intensive Learning, we had a focus on chemistry. The first thing we did during class was an answer on a Jamboard that presented the question: “What do the words ‘Acids and Bases’ make you think about?” The majority of responses consisted of different types of acids, such as citric and malic, acidic foods, such as vinegar and lemon, and bases in DNA, or ATGC (adenine, thymine, guanine, and cytosine). Later in class, we learned what acids and bases really are using a series of experiments with litmus papers, universal indicators, and PPN. Each of these three would react with the liquid bases/acids differently by changing color, or staying the same, (indicating acidity, or indicating a base) depending on the change of color. After that, we explored more by watching a video that explained why the reaction happens. In summary, bases met with acids cancel each other out, making a reaction.
After seeing what bases and acids were, we began setting up our lab. We began to learn about titration, which is adding a substance to another to make them equal. Our set-up for this lab included: a balance, 25-mL or 50-mL buret, stand with clamp, 125-mL or 250-mL Erlenmeyer flasks, magnetic stirrer, 1% phenolphthalein (PPN), potassium hydrogen phthalate, sodium hydroxide [NaOH(s)], and distilled water. Our buret was filled with our titrant, NaOH. A titrant determines the concentration of a substance, and a buret is the “delivery device,” which lets you know how many solutions you have added to the other substance. Our substance was KHP, which we mixed with water and PPN. Our KHP solution that we were analyzing is called the analyte, and we were trying to titrate this solution, meaning to neutralize it with NaOH. To begin the procedure we put the solution in the flask under the buret and began pouring. Once we began pouring the NaOH, we had to swirl the mixture every few increments to see if the solution would turn pink. We knew it was neutralized when the solution turned pink, but we had to be careful since if it was too pink (or magenta), it meant that it was over-neutralized.
After lunch, we were able to look at the percentage of acidity in liquids like vinegar. With our new knowledge of titration, we were able to find the data on how much NaOH (sodium hydroxide) was needed to change the color of the solutions containing vinegar. This then made us figure out the average molarity. Molarity is known as “the number of moles of solute dissolved in one liter of a solution” and this is what we used to be able to compare data. Everyone had a fun time being able to titrate and use different chemicals to change the color of the solution while learning more about titration as a whole.
By: Azra, Maddie, and Cole