We all love going to the ocean, but have you ever stopped and wondered what actually is in the ocean? Yes, we know that it contains salt water, but what kinds of elements can you find lurking in these waters? In this lab, you will be analyzing the different types of salts that make up the salt water in the ocean by Santa Monica, CA. You will be performing experiments to determine if the levels match the typical levels or if they are higher or lower than what is normally seen in these waters.
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Oceans are complex ecosystems. There is a wide array of animals, plants, and bacteria that reside within the Earth's oceans. Additionally, the ocean waters contain more than just the typical ions you would expect. If you have 1000 g of ocean water, typically 965 g is water and about 35 g are various salts. There are many different type of salts that can be dissolved in the ocean. Of the 35 g that is classified as being salt, the following ions are present:
As you can see, there are many ions that are floating around in the seawater. We can perform experiments to analyze seawater to determine if these numbers are accurate and to determine if there are other ions floating around in the water.
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Often times, we have solutions of acids and/or bases that we do not know the concentration of. A titration is the controlled addition of solution of known concentration/volume to a solution of known volume, but unknown concentration. We use titrations to determine the concentration of an unknown acid or base.
A titration stops once the equivalence point is reached. The equivalence point is the point at which the two solutions used in a titration are present in equivalent (the same) amounts. We use indicators to tell us where the equivalence point is. For a strong acid/strong base reaction, the equivalence point is always at a pH of 7. When we are at the equivalence point, we know that the Moles of acid = moles of base. |
You will design and run an experiment in this lab that tests for the amount of chloride and sulfate ions in a solution. You will test for this using titrations. Since this involves a great deal of extra chemistry knowledge, you will be reading the introduction to the lab in order to aid in your experimental design.
Swim with the Fishes Part I Swim with the Fishes Part II Swim with the Fishes Part III Using this introduction and the information that was provided to you on this webpage, you need to design an experiment to help answer the following issues: 1. What is the density of the seawater sample and the total mass of the dissolved solids? 2. What is the concentration of chloride ions in the seawater? 3. What is the concentration of sulfate ions? This lab will need to be broken up into 3 parts in order to properly designed. |