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The following crime is true; only the names have been changed to protect the guilty. This is Dragnet: HS Chemistry! RodneyM sat in his seat during his online Chemistry class. It was not hard, but it had been taking a toll on him. Mrs. Rathbun asked, “Since we have six H atoms here, and six OH molecules there, how many molecules of water can we create?” Quickly, RodneyM typed in his answer.

 

RodneyM: 12H2O.

 

“No, Rodney,” Mrs. Rathbun said, “it is 6H2O.” 

 

RodneyM: Oops!

 

Because Rodney made similar mistakes over and over, he almost got a B in the chapter, but he quickly straightened his act and kept his A.

 

As the HS Chemistry class goes on, the topics get harder and harder--to the point if you do not watch very carefully, it is very easy to make a mistake. During this month, the HS Chemistry class has mostly covered Polyatomic Ions, Molecular Polarization, and Acids and Bases. A polyatomic ion is a group of atoms that gain or lose one or more electrons. Carbonate for instance, the stuff that Coke Bottlers put in soda, is CO3-2. The -2 is the charge, or how many extra electrons are in the Polyatomic Ion. Because electrons are negative, any extra electrons will add a negative charge to the Ion. This is the same with adding a positive atom or ion, the polyatomic ion becomes positive. This is useful because many times these Polyatomic Ions are added to an element, and if the chemists know the charge of the Ion, then they can tell how many atoms and Ions are needed.

 

Because of the three-dimensional structures of compounds and Polyatomic ions (I didn’t know they had three dimensions until this class!), certain compounds can have a slight charge some of the time. H2O has a bent structure, so it looks kind of like a V with the O at the bottom of the V and two Hs at the top. O wants electrons more than H does, so O will pull at Hs electrons harder than H will pull at Os electrons. Because of this, O will have a negative charge part of the time, and H will have a positive charge during that time.  This means, H2O is polarized part of the time and will have an electrical charge. If this is confusing, don’t worry, it gets better.

 

When I said better, I meant the bad kind of better. The next lesson is all about Acids and Bases. You can find some major differences between acids and bases—as long as you like tasting possibly deadly chemicals. Acids taste sour, like a lemon (Citric Acid), while bases taste bitter, like soap… if you have ever tasted soap. Fortunately, there is an easier way to test which is which without dying. Acids turn blue Litmus paper red, while bases turn red Litmus paper blue. After learning about the properties of acids and bases, the next thing to learn is the definition of an acid and base. An acid donates H+ ions, and a base accepts H+ ions. Because acids donate H+ ions and bases accept H+ ions, Acids and bases can react together. The outcome? Normally, it is water and an ionic compound, known to scientists as salt. Salt is defined by chemists as any ionic compound. With this information, we can now predict what the outcome will be when someone combines an acid and a base.

 

The next concept is Molarity--a concentration unit that tells how many moles of a substance are in a liter of solution, or # moles/ # liters. Sometimes, a scientist wants to make a more diluted concentration of an acid. Instead of pouring out a little bit of the acid and measuring the right amount, they will pour water into it. The equation is M1 V1 = M2 V2. In other words, the molarity of the solution times the volume of the original solution equals the molarity times the volume of the new solution. Why is this important? Because certain chemicals and elements are deadly at high concentrations. For example, as of this minute, you are breathing poisonous gasses, however because the concentration is so low, it does not affect you. Also, while drinking hydrochloric acid can kill you, if you have it in an extremely low concentration, you should be alright.

Titration is the process of slowly reacting a base with an acid until just enough acid has been added to react will all of the base. If you put an indicator, normally litmus paper, into acid, it will turn red. As you add Base to the acid, the redness stays. Once you add enough base to the acid to completely neutralize the acid, the next drop of base will turn the litmus paper blue. By doing this, you can find out the concentration of an acid or base.

 

Tune in next month for Dragnet: HS Chemistry, where DericC will not study the textbook and gives wrong answers to all the questions in class! And have a great March!

 

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HS Chemistry English 8, section 5 HS Chemistry, Section 2 JH Latin 2