We touched on a few topics today:
1. Reviewed solutions and molarity
2. Dilution calculations, if you can remember how to use C1V1=C2V2, you will rock dilutions
3. We began to discuss why reactions occur. The first reaction type we looked at is precipitation metathesis reactions. If two (or more) aqueous solutions of ionic solutes are combined and a precipitate can form, the reaction will occur to generate that precipitate. We need to look at solubility rules to predict whether or not a combination will form a precipitate. Solubility rules are summarized in your textbook, Table 4.1 on page 154.
4. We talked about the importance of net ionic reactions in understanding the chemistry that occurs in a reaction. Net ionic equations describe chemistry. One more time, if you just want to explore the chemistry of a reaction, the net ionic equation will give you the best picture. Full molecular/formula equations are important to understand what's being combined (macroscale), but net ionic equations describe the chemistry. For example, if I want to make some silver(I) carbonate solid, I can go into the stockroom and grab a bottle of silver(I) nitrate and a bottle of potassium carbonate, dissolve some of each in water, and combine the solutions to make a silver(I) carbonate precipitate as described by the following equation:
2 AgNO3(aq) + K2CO3(aq) --> Ag2CO3(s) + 2 KNO3(aq)
If I really want to describe the chemistry of this reaction, the potassium and nitrate ions aren't really doing anything. The only reason they're there is because I need to balance the charge of the silver(I) and carbonate ions in the solid reagents I get from the shelf. To describe the chemistry, I can (and probably should) use the net ionic equation:
2 Ag+(aq) + CO32-(aq) --> Ag2CO3(s)
Don't forget the old MC assignment (due tonight) and the new MC assignment (due Friday).
1. Reviewed solutions and molarity
2. Dilution calculations, if you can remember how to use C1V1=C2V2, you will rock dilutions
3. We began to discuss why reactions occur. The first reaction type we looked at is precipitation metathesis reactions. If two (or more) aqueous solutions of ionic solutes are combined and a precipitate can form, the reaction will occur to generate that precipitate. We need to look at solubility rules to predict whether or not a combination will form a precipitate. Solubility rules are summarized in your textbook, Table 4.1 on page 154.
4. We talked about the importance of net ionic reactions in understanding the chemistry that occurs in a reaction. Net ionic equations describe chemistry. One more time, if you just want to explore the chemistry of a reaction, the net ionic equation will give you the best picture. Full molecular/formula equations are important to understand what's being combined (macroscale), but net ionic equations describe the chemistry. For example, if I want to make some silver(I) carbonate solid, I can go into the stockroom and grab a bottle of silver(I) nitrate and a bottle of potassium carbonate, dissolve some of each in water, and combine the solutions to make a silver(I) carbonate precipitate as described by the following equation:
2 AgNO3(aq) + K2CO3(aq) --> Ag2CO3(s) + 2 KNO3(aq)
If I really want to describe the chemistry of this reaction, the potassium and nitrate ions aren't really doing anything. The only reason they're there is because I need to balance the charge of the silver(I) and carbonate ions in the solid reagents I get from the shelf. To describe the chemistry, I can (and probably should) use the net ionic equation:
2 Ag+(aq) + CO32-(aq) --> Ag2CO3(s)
Don't forget the old MC assignment (due tonight) and the new MC assignment (due Friday).
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