Theoretical and Actual Yield

Theoretical Yield- the amount of a certain product that is ideally produced given the amount of reactant used 

1. Convert reactant to moles

2. Multiply by the molar ratio

3. Convert back into grams

Actual Yield- the actual amount of product yielded due to errors

1. This is the amount in grams of a particular product that you end up with

Percent Yield- the amount of actual product you end up with in comparison to the theoretical yield

1. Divide the actual yield by the theoretical yield

2. Multiply by 100

Example problems:

Additional Help:

http://youtu.be/LQN9lH9WAVQ

http://youtu.be/LQq203gyftA

Limiting Reagents

A limiting reagent is the chemical in a compound that will be used up first, there by "limiting" the chemical reaction. There are 2 methods that can be used to determine a limiting reagent as pictured below...

Method 1:

Method 2:

Personally, I like to use the method in which I have modified into simpler steps which are:

1. Convert each reactant to moles

2. Multiply by molar ratio

3. Concert back into grams

4. The smaller number is the limiting reagent

Here are some links that should help:

http://www.chemteam.info/Stoichiometry/Limiting-Reagent.html

http://youtu.be/QgrVvB56Mj4

Stoichiometry Lab

Over the past few days, we have conducted a lab in which we placed an iron nail into a solution of copper(II) chloride and water. We then observed the synthesis of copper on the nail after a suprisingly short amount of time. Next, we removed all the liquid and let the copper dry out before taking the mass of it to determine whether the reaction the occurred on our nail was with Fe2+ or Fe3+. We discovered that our reaction involved Fe3+ as the theoretical yield for that was closer to our actual yield than was the theoretical yield for Fe2+.

Here are some pictures from the lab:

After about 3 hours of being submerged in the copper(II) chloride and water solution.

After 1 day of remaining in the solution.

After we drained out a majority of the liquid.

Final copper product after drying for 2 days.

Stoichiomestry for Starters

We recently started the stochiometry unit, and I feel as if I have a pretty good grip on the ideas. I got a 90% on the last weekly quiz, and I have gone over the concepts several times. Therefore, I think I am going to do pretty well on the unit test, but the main things I'm going to need to study are...

1. Limiting Reagents (help- http://youtu.be/nZOVR8EMwRU )

2. Theoretical/Actual Yield (help- http://youtu.be/LicEaaXhlEY )

3. Memorizing Polyatomic Ions (flash cards- https://quizlet.com/782126/common-polyatomic-ions-flash-cards/ )

Acid/Base Reactions

Acid base reactions are reactions between an acid and a base that form salt and water as products.

Here are some key things to remember about acid/base reactions:

1. The driving force in these reactions is the production of water.

2. Strong acids protonate completely.

3. Strong bases disassociate completely.

To differ the difference between a strong or weak acid/base, refer to the following.

Also, here a some links to help you!

http://www.britannica.com/science/acid-base-reaction

http://youtu.be/ANi709MYnWg

http://youtu.be/HdmCagtasYg

Reactivity Series Lab

Yesterday we did a lab in which we were given chemicals that we were supposed to combine with elements in order to find out which elements were most reactive. The elements we used were Pb, Cu, Ca, Mg, Sn, and Zn which were all combined with H20, HCl, CuSO4, and AgNO3. Below is which reactions we observed along with the reactivity series that we came up with.

And here are pictures of some of the reactions that occurred:

Solubility Rules Lab

For this lab, we placed 5 drops of one chemical in each spot of a well place then added 5 drops of another chemical to see if they would go through a chemical reaction. We could tell if they reacted because they would form a solid, and in some cases, they would change color. Below is pictures of what the reactions look like when they form a solid.

And here are some chemicals that we used:

Lastly, here's some links with more information:

http://youtu.be/UVVgFEWxF24

http://youtu.be/KVZ_KS45rVg

RedOx Reactions

Key points of RedOX(oxidation) reactions:

1. They are all single replacement.

2. The metals always switch places.

3. The reactions are based off of the reactivity series.

4. The driving force is the transfer of electrons.

5. The element that loses electrons is oxidized and also known as the reducing agent.

6. The element that gains electrons is reduced and also known as the oxidizing agent.

Here are some of my notes from class on oxidation:

And here are some examples:

Here are some videos to help!

http://youtu.be/lQ6FBA1HM3s

http://youtu.be/RX6rh-eeflM

Double Replacement Reactions

Double Replacement Reactions are when two compounds react to form two new compounds. Represented with letters, they look like this...

Two things to remember are:

1. The metals are always the elements that switch places.

2. One element resulting from this reaction will always be solid, assuming that the reaction occurs.

Don't forget the solubility rules linked here to determine which compound product will be soluable...

http://www.chem.sc.edu/faculty/morgan/resources/solubility/

http://youtu.be/7hVKb4ROjZw

Lab Fails: Part 2

Yesterday in class, we participated in the formula or a chloride lab. However, this so the second lab this week that has gone horribly bad for me. We were suppose to heat zinc and HCl to evaporate the water in order to determine the formula for zinc chloride. We didn't get this far though because as we were heating our mixture, it began to foam which we later found out was due to the foul before us rinsing out the beaker improperly, so there was still soap in it. We had to restart, and the same thing happened again, so we restarted for a 3rd time but after the first 2 failed attempts, we didn't have time to finish. Fortunately, Ms. Frenkenberg was kind enough to give us some data to use. Below are some pictures of the lab and calculations with the days we were given.

And here's some links of what is supposed to happen:

http://swc2.hccs.edu/pahlavan/intro_labs/Exp_12_Empirical_Formula.pdf

https://m.youtube.com/watch?v=M2BqSLBDf00

https://m.youtube.com/watch?v=EJf0cwJ_QOw

Hydrate Lab

Yesterday I was able to do my first real lab in chemistry because my partner and I passed the pre-lab quiz. For this lab, we removed the water from the the hydrate Copper Sulfate x nH20. To do this, we first determined the mass of the test tube we would be using. Then we added a thumb-width amount of the hydrate to the test tube and took the mass again with the same scale. Then we heated it with a Bunsen burner 2 times, taking the mass once again after each heating. The hydrate was supposed to go from it's blue color to a white ash color. However, we discovered that we didn't hear it gently enough at first, so we ended up burning the hydrate and it turned brown on the outside while remaining rather blue within. Although we did mess up our results by burning the hydrate, we ended up with about a 28% error for n, as it was supposed to be 5 and we got about 3.8, which isn't too shabby for cooking our crystals way past well done. Below are some pictures of the lab as well as our data.

Moles with Compounds

AlsTo find the molar mass of compounds, follow these steps:

1. Determine the mass of each element in the compound.

2. Determine the number of each atom in the compound.

3. Multiply the number of each atom by its mass and add all of the products together.

4. This sum is going to be your answer and it should be in grams per mole(or g/mol).

Below are some examples from our notes...

Also here is a video to help explain in more detail

http://m.youtube.com/watch?v=zJDhsbjAEtI

Converting to Moles

Moles are the measuring unit that we will be using throughout the year, so it is important that we understand how to convert into moles. With single elements, there are 4 easy steps to follow:

1. Decide what is being asked(starting unit and ending unit)

2. Write down all the given information

3. Use the starting unit to follow to mole roadmap(pictured below) to convert into the ending unit

4. Round to the correct number of significant figures. This will be the least amount of sig figs in any of the present values in the conversions.

Also here are some websites to help with conversions:

http://www.chemteam.info/Mole/Grams-to-Moles.html

http://chemistry.about.com/od/workedchemistryproblems/a/molegramconvert.htm

Do you dig sig figs?

Significant figures have a common appearance in chemistry, and they seem difficult at a glance, but aren't too complex when you go beneath their surface. Rules to remember at that the zeros before a decimal are not significant unless sanwhiched between 2 whole numbers. Also, the zeros to the right of the decimal follow the same rule being that the are significant if between 2 while numbers. Lastly, zeros at the end of the digits to the right of the decimal are significant as well. 

States of Matter

To help us the states of matter and properties of each state, we did an activity. In the activity, we went to different stations, and we had to decide either the state something was in, or wether it was a compound, element, or solution. This helped me learn the difference between all of those because I got hands on experience which is beneficial to myself as well as several other classmates that participated in the activity.

Thoughts on Aspirin Lab

This week in class we did a lab synthesizing apirin. However, I did not pass the pass the pre-lab quiz because I did not read the lab thoroughly enough. I did have a study hall all week in class along with some others, and I was able to update my blog! Next time, I will definitely know the lab front and back before we take the pre-lab quiz, so I don't have to sit out on any more labs!

Happy Mole Day!

Today is mole day and to celebrate, we were assigned the task to see a mole ourselves. I decided to make a cheetah girl mole, named Raven Si"mole", because I had some cheetah print fabric already, so it would be easiest. I had to hand sew it because I don't know how to work a sewing machine, and I also had to stuff it with tissues since I didn't have stuffing. Below is my mole as well as several other people's miles from today's celebration.

The Founding Father of the Atom: Part 3

Ernest Rutherford is the subject of my final chapter in this series. He first discovered a concentrated area in the center of the atom which is know today to be the nucleus. Secondly, he defined the atom to be mostly empty space which is called the electron cloud because there is not a known barrier at the end of an atom to confine it to a certain space.

The Founding Fathers of the Atom: Part 2

John Dalton may have been the first to give us an idea of what an atom is, but JJ Thomson discovered a highly important part of the atoms. Thomson found that there were tiny electrons in the atom, and in his theory, he states that they are scattered throughout the atom. This model is referred to as the chocolate chip model where the electrons are the chocolate chips, and the rest of the cookie is the remaining mass of the atom.

Thoughts on Radioactive Decay Lab

I found this lab useful because we cut a piece of paper, that was colored on one side only, into over 500 pieces. We then continued to place them in a cup, dump them out and count how many landed with the color side up. These were the "atoms" that decayed, so they were taken out and the process was repeated 5 more times. This lab really helped me put a visual in my head to radioactive decay and how it occurs. It was also fun to touch on forensic science in a way as we had to identify a body based on the amount of the certain substance left after 60 years.

Beanium Lab

Today we did a lab that simulated finding isotopes of a new element, Beanium. There were 4 types of beans and we sorted each of them along with finding the mass of each isotope. Then we found the average atomic mass of the element with the formula.

The Founding Fathers of the Atom: Part 1

The atom has been around since history began, but there are three scientists that helped discover traits about the atom to help make it realistic to the human eye today. The first of the three is John Dalton who proposed his famous atomic theory in which he stated that all matter is made of atoms, all atoms are indivisible and indestructible, and compounds are formed by a combination of two or more different types of atoms. Although his theory has proven to be partially false, it is still considered the first major discovery towards identifying the atom and what the atom really is because it gave people a glimpse of how important atoms are for the first time.

Naming Acids

If you were curious as to how you name compounds with acids, you can use this flowchart to help.

Does the anion contain oxygen?

I                                   I          

                                                               No                               yes

                                              Hydro-                                      check the ending of the anion name

                                              + anion root                                            I                      I

                                               + ic_______

                                            hyrdo(anion root)ic acid         anion or element root        anion/element root

                                                                                                 + -ous____________           + -ic____________

                                                                                                 (root)ous acid                       (root)ic acid

How do you tell which type of compound something is?

To identify the type of compound, you can simply use this flow chart to determine which type it is.

Is it a bianary compound?

                                                                                       yes

Is metal present?

     No                                               yes

                                            Type III                                         Does metal form more than one cation?

                                                                                               I                                         I

                                                                                                      No                                              yes

                                                                                               I                                         I
                                                                                                         Type I                             Type II