descriptive-chem

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Descriptive Chemistry, Solubility Rules, and Reaction Types Solubility Rules  Precipitation Equilibrium Single Replacement Reactions  Double Replacement ReactionsActivity Series of Elements Combustion Reactions Decomposition Reactions Acid Base Reactions Descriptive Chemistry

Solubility- The largest amount of solute that is capable of being dissolved in a solvent. This is based on the strength of  intermolecular forces.

Aqueous solutions- A solution dissolved in water  __Solubility Rules__ ***very important for reaction writing!!** *  CASHnGIA
 * 1) All ammonium, potassium, and sodium compounds are soluble in water
 * 2) All acetates, chlorates, and nitrates are soluble in water
 * 3) All chlorides are soluble in water except in water except those of silver, mercurous mercury, and lead. (Lead chloride is slightly soluble in cold water and readily soluble in hot water.)
 * 4) <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; text-align: left;">All sulfates are soluble in water except those of barium and lead. Calcium, strontium, and silver sulfates are only slightly soluble in water.
 * 5) <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; text-align: left;">Carbonates, phosphates, oxides, silicates, sulfides, and sulfites are generally insoluble in water except those of ammonium, potassium, and sodium.
 * 6) <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; text-align: left;">All hydroxides are insoluble in water except those of ammonium, potassium, sodium, barium, calcium, and strontium. (Those of barium, calcium, and strontium are only slightly soluble in water.)
 * Here is a good way to remember these rules:***

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Just because a substance is soluble, doesn’t mean that it dissolves completely!! To find out how soluble it is you need to use Ksp<span style="background-color: rgb(255, 255, 255);">, the solubility-product constant.====== __**Precipitation**__ (contributed by: Shannon R) what is a precipitate?? well a precipitate is a solid that appears when two liquids that are insoluble are mixed. Generally these solutions are aqueous and made up of metallic cations and nonmetallic anions. other solutions can make solutions of acids such as sulfuric acid and hydrochloric acid, or bases such as ammonium oxide or sodium oxide. Knowing whether or not a precipitate is formed is all apart of knowing your solubility rules which are listed above NaCl(aq) + AgNO3(aq) ---> NaNO3(aq) + AgCl (s) NaNO3 is soluble. AgCl is not soluble. (contribution by Mr. Daddio)

<span style="font-family: 'Comic Sans MS',cursive;">** __Types of Reactions__ ** <span style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);"> <span style="background-color: rgb(255, 255, 255);">  [|Single Replacement Ex.]  [|Double Replacement Ex.] 
 * <span style="color: rgb(0, 0, 0); background-color: rgb(255, 255, 255);">Equilibrium ** <span style="background-color: rgb(255, 255, 255);">- When the forward and reverse reac tions occur at the same rate. This is shown by a double arrow.
 * Single Replacement**- Reactions where one element replaces another element in a compound.
 * Double Replacement**- Reactions where two elements in different compounds switch places.
 * Make sure you use the Activity Series of Elements to determine if it is possible to perform a replacement reaction. If the element that is being replaced has a higher reactivity than the one replacing it, it can not work.*

Metals (decreasing reactivity) Lithium Potassium Barium Strontium Calcium Sodium Magnesium Aluminum Manganese Zinc Chromium <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; text-align: left;"><span style="font-family: 'Comic Sans MS',cursive;">Iron Cadmium Cobalt Nickel Tin Lead Hydrogen Antimony Arsenic Bismuth Copper Mercury Silver Palladium Platinum Gold

Nonmetals (decreasing reactivity)

Fluorine Chlorine Bromine Iodine  [|Combustion Ex.]  [|Decomp Ex.]  [|Click here for a video with great examples of single and double reactions, combustion reactions, synthesis reactions and decomposition reactions!] <span style="color: rgb(0, 114, 255);">Video contributed by Perrin Duvall.
 * Combustion Reactions**- Reactions that release heat by reacting with oxygen and creating products that include carbon dioxide and water.
 * Decomposition Reactions**- Reactions that happen when there is enough energy to break bonds to create products that are elements or smaller compounds than in the reactants.

Weak Acid, Weak Base- Reactions where protons are transferred from the acid to the base and the products are the conjugate acid and conjugate base. <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; background-color: rgb(255, 255, 255); text-align: left;"> Strong Acid<span class="wiki_link">, Weak Base- Reactions where a hydrogen ion hooks on to the weak base to form a positively charged ion as a product. [|Strong Acid, Weak Base Ex.] <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS'; text-align: left;"> <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; background-color: rgb(255, 255, 255); text-align: left;"> <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS'; text-align: left;"> <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; background-color: rgb(255, 255, 255); text-align: left;"> <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS'; text-align: left;"> <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; background-color: rgb(255, 255, 255); text-align: left;"> <span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; text-align: left;"> Strong Base, Weak Acid- Reactions where a weak acid gets ionized, and then the hydrogen ion becomes neutralized with hydroxide to form water. Products are water and a negatively charged ion [|Strong Base, Weak Acid Ex.]
 * Acid Base Reactions**

Strong Acid, Strong Base- Reactions that use double replacement to form water from the positive hydrogen ions and negative hydroxide ions in the reactants. [|Strong Acid, Strong Base Ex.]

Titrations- An acid base reaction used to find the concentration of an acid or base by neutralizing it with another acid or base of unknown concentration

Here is the set up for a general acid base titration- [|Citation]

In the images below, a titration between the base, Sodium hydroxide, and the acid, acetic acid. The pink solution in image C shows that the reaction has reached its equivalence point. It is caused by the acid/base indicator, phenolphthalein, which indicates a basic solution.

[|Example_4.7.jpg]  [|Click here for a great site on Titrations! (][|added by Rachael)] <span style="color: rgb(0, 0, 0); font-family: 'Comic Sans MS';"><span style="display: block; color: rgb(0, 0, 0); font-family: 'Comic Sans MS',cursive; text-align: left;">__ ** <span class="wiki_link">Descriptive Chemistry **__ The flame test was one of the first analytical methods used in Chemistry. Flame tests are used to identify specific metals or metal ions in a compound. They are most reliable with Group 1 metals. For other metals in which other methods are more reliable, flame tests can be used as hints. When a sample of the metal element, compound, or solution being tested is heated over a Bunsen burner, the metallic ions should give off a characteristic color. Each metal, theoretically, has a different color, but the difference may not be big enough to be seen by the naked eye. (For more information on this concept, please visit the "Flame Test Colors" section of the Atomic Theory and the Periodic Table page.) Flame tests definitely have their pros and cons. First off, they are simple and very easy to set up, complete, and clean up. If the observer is working with one particular metal, it is much easier for him or her to deduce what that element is bsed on the color of the flame. However, flame tests may not be the most reliable because the results are based on what the observer sees, and everyone can see things a little differently. Besides, not all metal ions give flames with color. Also, if the observer is experimenting with a compound, mixture, or solution of metals, a mixture of colors could appear as the flame color. This makes it much more difficult to find out what the different metals are and can lead to incorrect results.
 * __Flame Tests__** (by Cheryl Leighton)

Colors of Ions in Solution **

<span style="font-family: 'Comic Sans MS',cursive;"><span style="font-family: 'Comic Sans MS',cursive;">Aqueous Ion Color s **<span style="font-family: 'Comic Sans MS',cursive;"> <span style="font-family: 'Comic Sans MS',cursive;"> Cu 1+ Green Cu 2+ Blue <span style="font-size: 11pt; font-family: 'Comic Sans MS',cursive;">Fe ions Yellow to red-orange (depending on anion and charge of Fe); in rare cases, can form complex ion with a deep blue color <span style="font-family: 'Comic Sans MS',cursive;"> Fe 2+ yellow-green (depending on the anion) Fe 3+ orange-red (depending on the anion) Co 2+ Pink Cr 3+ Violet [Cr(NO 3 ) 3 to Green (CrCl 3 ) Ni 2+ Green Mn 2+ Pink Pb 3+ blue-green (Pb 2+ and Pb 4+ are colorless) V 2+ violet V 3+ blue-green MnO 41- Purple (Mn w/+7 oxidation state is purple) CrO 42- <span style="font-size: 11pt; font-family: 'Comic Sans MS',cursive;">Yello w <span style="font-family: 'Comic Sans MS',cursive;"> Cr 2 O 72- Orange Cu(NH 3 ) 42+ Dark Blue; produced when ammonia is added to Cu 2+ solutions FeSCN 2+ Red-brown, Wine-red to dark orange CoCl 42- Blue (Co 2+ with HC1 will form a CoCl 2- complex that is blue) Ti(H 2 O) 63+ Purple A1 3+, Li 1+ , Na 1+ , K 1+ , Mg 2+ , Ca 2+ , Ba 2+ , Sr 2+ , Zn 2+ are colorless aqueous ions and most of their solid <span style="font-size: 11pt; font-family: 'Comic Sans MS',cursive;">salts are white. Transition element ions with partially filled d orbitals tend to release colored light. <span style="font-family: 'Comic Sans MS',cursive;"> F 2 Pale-yellow gas C1 2 Green-yellow gas Br 2 <span style="font-size: 11pt; font-family: 'Comic Sans MS',cursive;">Red-brown liqui d <span style="font-family: 'Comic Sans MS',cursive;"> I 2 Dark-violet vapor & dark metallic looking solid S 8 Yellow, odorous solid NO Colorless gas; associated with reactions between metals and dilute HNO 3 NO 2 Brown gas; associated with reactions between metals and concentrated HNO 3 PbI 2 Bright yellow precipitate <span style="font-size: 11pt; font-family: 'Comic Sans MS',cursive;">Metallic sulfides Sulfides of transition metals tend to be black <span style="font-family: 'Comic Sans MS',cursive;"> Fe 2 O 3 Reddish brown (rust) <span style="font-size: 11pt; font-family: 'Comic Sans MS',cursive;">Metallic oxides Oxides of colored transition metal ions tend to be colored
 * <span style="font-family: 'Comic Sans MS',cursive;">Assorted Molecules and Compounds **

Bibliography

http://forums.studentdoctor.net/archive/index.php/t-191542.html __Chemistry: The Molecular Nature of Matter and Change__ by Martin S. Silberberg __Chemistry and Chemical Reactivity__ by Kotz and Treichel __Chemistry: Principles and Reactions__ by Masterton and Hurley