Copper (II) Chloride and Iron Lab

Today in class we started the Copper (II) and Iron Lab! To pass the prelab, we had to answer a basic stoichiometry problem correctly.

All we did for the first day was first weigh an empty baby food jar, a nail scratched with steel wool, and copper (II) chloride.

We added water and the copper chloride to the jar, stirred till it dissolved, and added the nail.

Here are some pictures of the process:

Now we will wait two days for the copper chloride to react with the nail. 

Percent Yield

To find the percent yield, things are actually pretty easy!

All you have to do is take the actual yield divided by the theoretical yield and multiply that by 100.

I remember this because anything actual comes over anything theoretical in real science.

You just have to remember that your percent yield will always be less than 100 due to error, whether it be human error, machine error, or unknown error.

Finding percent yield can be pretty disappointing, too. It's like baking a batch of cookies and starting with all of this:

http://noentreecakes.com/wp-content/uploads/2015/03/Baking-Ingredients.jpg

Only to end up with this:

http://upload.wikimedia.org/wikipedia/commons/thumb/6/61/Single_chocolate_chip_cookie.jpg/300px-Single_chocolate_chip_cookie.jpg


Here are some websites that'll help you if you're struggling:

https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/mass-relationships-and-chemical-equations-3/reaction-stoichiometry-44/calculating-theoretical-and-percent-yield-234-4704/

http://www.sparknotes.com/chemistry/stoichiometry/realworldreactions/section2.rhtml

How to find the Excess

While studying for our unit test Monday, I found this source from another chemistry teacher online that made this chapter REALLY easy to understand! One of the most helpful things i took from his page was the simple algebraic equation that gave me the amount of excess product without having to set up another stoichiometry problem.

Here's the equation:

original amount of excess reagent - org. amnt of excess reagent(amount of product actually formed/amount of product excess reagent can make)

It helped me cut down the time it was taking me to find the excess product, and helped me make this chapter a little bit easier.

Here's the webpage if you wanted to check it out!

 http://misterguch.brinkster.net/chapter12.pdf

By the way, here is a random fun fact about stoichiometry from the page:

Stoichiometry

The Basics of Stoichiometry:

Step 1: Convert amount of substance A from grams to moles
Step 2: Multiply by coefficient/molarity ratio
Step 3: Convert substance B from moles to grams

https://www.chem.tamu.edu/class/majors/tutorialnotefiles/Stoichmap.gif


And that is all.....until you get to alterations.

Stoichiometry is all about taking that basic process of solving a problem and changing it and manipulating it to get the desired answer.

If you need any help understanding the basics of stoichiometry, check out these links:

https://youtu.be/SjQG3rKSZUQ

https://youtu.be/wUckvmyvMi8

http://www.chemteam.info/Stoichiometry/Stoichiometry.html