Classifications

There are three umbrellas of chemical reactions:

• Formation of a solid
• Formation of water
• Transfer of elections

In the formation of a solid, double replacement reactions take place. On the reactants side, both reactants must be aqueous. On the product side, one product is insoluble and one product is soluble. 

In the formation of water, a strong acid and a strong base must react in order to form water and a salt. If the acid and base are not strong, they will not split. Double replacement reactions also take place in this type of reaction. 

If the reaction does not fit into either of these categories, it is a redox reaction. There are four types of redox reactions: single replacement, synthesis, decomposition, and combustion. 

Here is a link to practice recognizing reactions: Classification Quiz

Transfer of Electrons: Redox notes

In class yesterday, we learned about redox reactions and the different types. In redox reactions, electrons are transferred from the metal to the nonmetal. If a species loses electrons, it is said to be oxidized, and it is the reducing agent. On the other hand, if a species gains electrons,it is said to be reduced, and it is the oxidizing agent. A way to remember this is:

http://www.chemguide.co.uk/inorganic/redox/definitions.html

In redox-single replacement reactions, the metals change particles and the driving force is the transfer of electrons. The reaction is based on a reactivity series. Something to remember is "like attacks like." So, a metal attacks a metal, and a nonmetal attacks nonmetals. Below is an example:

http://makahiki.kcc.hawaii.edu/chem/single_displ_rxn.html

Next, we practiced synthesis reactions. Synthesis reactions occur when two or more reactants combine to form one product. The general formula is A + B = AB. Decomposition reactions are the opposite, so one reactant produces two or more products. The general formula for decomposition reactions is AB = A + B.

Lastly, we reviewed combustion reactions as our last redox reaction. In a combustion reaction, the reactants always include water, and produce carbon dioxide and water. Below is an example: 

http://www.angelfire.com/un/sch3u1/combustion.html

Here are a couple videos that further explain redox reactions:

Tyler DeWitt

Bozeman Science

Reactions that form water notes

Today in chemistry class, we took notes over reactions that form water. These reactions include an acid and a base, and the driving force is the production of water. A salt is also produced. For example:

http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/acidbase.html

Acids can be strong or weak and bases can be strong or weak.

Strong acids:

• produce H+
• protonate completely 
• are strongest when oxygens outnumber the hydrogens by 2 or more
• HCl, HBr, HI

Strong bases:

• contain an -OH anion
• completely disassociate
• All group 1 and 2 metals cations plus an -OH anion are strongest

Weak acids and weak bases:

• do not protonate completely
• are not on the memorized list

Here is a link that further explains strong/weak acids and bases: ChemTeam

Here is a link to practice determining is an acid is strong or weak: about chemistry

Below is also a molecular, complete, and net force equation using strong acids and bases that we solved in class: 

Driving Forces in Chemistry

We learned a somewhat confusing lesson in chemistry class today. Mrs. Frankenberg discussed driving forces in chemical reactions. Two components will react if there is at least one driving force present. The driving forces of chemical reactions are:
-Formation of a solid
-Formation of water
-Formation a gas
-Transfer of electrons
There is a link to a video below that explains these and indications of chemical reactions

However, we mainly focused on the formation of a solid today, which is also known as precipitate. With these, double replacement precipitation reactions take place. In a double replacement reaction, 2 compounds replace 2 compounds by having the positive ions (cations) switch with each other. The format of this reaction looks like this: 

http://socratic.org/questions/is-this-reaction-a-double-replacement-reaction-fe-c5h5-2-bf4-nab-c6f5-4-fe-c5h5-

In addition, for this type of reaction to take place, the compounds that are the reactants must be ionic and aqueous and one of the products must be a solid. We must memorize the solubility rules to check if a chemical equation has a driving force.

http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=jpg::::::/sites/dl/free/0023654666/650262/Solubility_Rules_4_02.jpg::Solubility%20rules

Driving Forces Video

Start to a new unit

Today in chemistry class, we started our new unit: Chemical Reactions. We learned about several new and old concepts . I didn't find the lesson too difficult. However, I do need to review a few old ideas. First, we talked about clues of chemical reactions, and how they are different from physical changes. Below is a picture of some chemical reaction changes.

http://chemistrysaanguyen.weebly.com/61-evidence-for-a-chemical-reaction.html

Next, we discussed chemical equations and reviewed how to balance them. We learned that we can only change coefficients and not subscripts. In the picture below, you can see that the equation is balanced. On the left (reactants) there are 4 hydrogens because the hydrogen coefficient of 2 multiplies with the 2 subscript below the hydrogen. There are also 2 oxygens on the left. On the right (products there are 4 hydrogens and 2 oxygens to balance the equation. 

http://www.mikeblaber.org/oldwine/chm1045/notes/Stoich/Equation/Stoich01.htm

Here are a couple links to practice chemical equations and nomenclature. 

Jefferson Lab Balancing Act

Chem Team Chemical Nomenclature

Percent Composition, Molecular Formulas, and Empirical Formulas

Today in class, we learned a lot of things. At first, I found the new concepts very easy, but as we continued, they got harder and harder. First, we practiced percent composition. I slightly remembered this from earlier in the school year, and remembered some of the steps as we were doing the questions. Below, I posted some practice questions that I can use while studying for the exam. Next, we learned about Molecular formulas vs. Empirical formulas. Molecular formulas can  be Empirical formulas if they can not be reduced any more. For example, the molecular formula of a compound may be P₄O_{10 but the empirical formula would be} P₂O<sub>5. There are more practice problems below for those formulas and other practice quizzes for the questions we practiced with these formulas in class today. 

Percent Composition Link</sub>
Molecular and Empirical Practice
Calculate empirical formula with percent composition data given

Hydrate Lab

In class today, my partner and I successfully passed the pre-lab quiz for the Hydrate lab. I was really nervous that I wouldn't pass, but was very relieved once Mrs. Frankenberg approved of our answers. After we got our safety goggles, my partner and I picked a station. My partner measured the mass of the test tube and we both recorded it in the data table (picture below). After about 2 cm of CuSO4 hydrate was placed in the test tube, we recorded the mass and heated the blue solution until is turned whiteish-gray, making sure that it did not burn. After that we measured it and heated it again to ensure that we evaporated all the water in the solution. Again, we measured its mass and filled in our data table. Then, Mrs. Frankenberg looked at our data and said it looked good. So, my partner and I cleaned up our lab. However, we made the mistake of cleaning our test tube with the anhydrous with water. It reacted and hardened, making it very hard to clean. Next time, we definitely won't add water and will just throw the ashes in that trash-bin!
Here are a couple pictures of that lab below:

Molar Mass

We learned how to calculate the molar mass of a compound in class today. I found the concept easy to learn. However, I do need to review my polyatomic ions. 

This is one example we did in class. We still need to round to the correct number of significant figures in the end.

Magnesium chloride = MgCl₂ = 1(24.31) + 2(35.45) = 95.21 g/mol

Mrs. Frankenberg also taught us the diatomic ions. They are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. When these elements are sitting alone, you must double their mass from the periodic table to find their molar mass. 

For example, O₂ = 2(16.00) = 32.00 g/mol

Below, I posted a picture of the polyatomic ions that I can use to study and a link to practice calculating the molar mass of compounds before the exam. 

http://crescentok.com/staff/jaskew/isr/tigerchem/naming/a85.htm

molar mass quiz

Chemical Composition Notes

In class today, we took notes over chemical composition. I learned that a mole is a quantity of measurements and I was reminded that a mole is equivalent to 6.02 x 10^23 representative particles. Mrs. Frankenberg showed us how whole numbers tell us molar quantity in an equation. Here is an example that she showed us in class to demonstrate the concept:

2H₂O -----> 2H₂       +         O_{2
2 moles       2 moles           1 mole}

Next, we practiced problems with moles, and she gave us a handy conversion chart to use while we calculate:



Below are examples we did together in class. Note that we still need to round to the correct number of significant numbers in the end.

Here are a couple websites with more practice problems for converting with moles:
Chemteam: grams to moles
Chemteam: moles to grams

Pretest Reaction

In chemistry class today, we took a pretest over our next unit: Chemical Composition. I thought the test was difficult. However, once I learn the concepts in class, I believe that I will have a better understanding of what's on the exam. A couple terms I remember from the test were empirical formulas and finding the percent by mass. I have a couple pictures and links below that help explain these concepts.

http://quantummechanics.mchmultimedia.com/2011/general-chemistry-general-chemistry/004-empirical-formula-in-chemistry/

http://quantummechanics.mchmultimedia.com/2011/general-chemistry-general-chemistry/004-empirical-formula-in-chemistry/

Writing Empirical Formula Practice Problems

Percent Composition by Mass