Vitamin C Lab

This lab consisted of determining the vitamin C content of different juices. We got samples of pear, grapefruit, V8, and apple juices and compared these juices' vitamin C content to that of a standard solution. We used iodine as a indicator and dropped iodine into the juice samples until the juices turned blue. The grapefruit turned out to have the most vitamin C content, and the pear had the lowest vitamin C content.

Making the standard solution

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Lab set-up

                             

Adding drops of iodine to juice sample

                             

Hydrogen Peroxide Lab

Today we did the hydrogen peroxide "lab". We were not able to do the actual lab part of it and got data to calculate instead. We had to calculate the masses of the potassium permanganate and hydrogen peroxide solutions used and used that data to do a stoichiometry problem with molarity. It was a helpful practice with molarity and stoichiometry especially since I have been absent for the past few days. Lastly, we had to calculate a mass percent of the hydrogen peroxide using our data from previous calculations, and we learned about how hydrogen peroxide decomposes in light causing an inaccurate advertised percentage on the bottle.

Dilution Lab

Lab set-up

Lindsi measuring the water

                                        

In this lab we had to practice calculating serial dilutions through diluting food coloring in water. First we started with a solution with ten drops of food coloring then gave it a series of dilutions until it became clear again. It took six dilutions to bring the solution back to clear. I found that the color gradient in the end looked really neat. It was a helpful practice in calculating dilutions.

It Will Get Better

Today we had a quiz over the unit so far, and honestly I cannot tell you at this moment what this unit is about. Coming back from break has really messed me up, and the fact that I cannot explain to you what exactly we are doing in this unit should show how well I understand the material. The quiz today was... rough. I know that the quiz itself was not the most challenging one we took all year, but because I am still so shaky on these concepts, I was not able to confidently answer as many questions as I would have liked to. I vaguely remember dilution questions and some things about molarity, but a lot of times after quizzes my mind just deletes that small 55-minute portion of my life taking that quiz and I forget everything I had just done. This unit is turning out to be a bit more difficult than usual because I'm still on vacation mode. Oh well, it will get better... hopefully.

Helpful Study Links:

Molarity Explanation

Molarity Practice Problems

Molarity and Stoichiometry

Solution To Dilutions

We started the new unit, Aqueous Solutions, recently and the first formula we learned about was M1V1=M2V2. It is a concept that is pretty easy to grasp once you get the algebra down and are able to identify which part of the problem coincides with which part of the formula. So far, the unit is going well and I am excited to have another math-based unit.

Solution to Dilution Video

More Help:

Dilution Practice Problems

Dilution Notes and Practice

¡Copper (II) Chloride Lab Day 1 & 2!

Day 1:

We weighed all of our materials on the first day, and put our nail on the copper (II) chloride. The nail turned red and it was pretty cool.

The nail turned red as soon as it hit the CuCl2

Day 2:

After letting the nail soak overnight, we found that the solution turned green and a bunch of poop-looking copper was a product from the reaction. We then had to get rid of the nail and all the liquid by siphoning and pour water into the jar with the copper and siphoned off the water as well. The copper is left in the jar for the weekend and now we wait.

The "swamp water" after the reaction overnight

       

The nail after it reacted with the CuCl2

After siphoning the water from the product

Percent Yield

We learned the final part of our stoichiometry unit today: percent yield. Similar to the other part of the unit, it is very math driven, and is not difficult once you learn how to set the problems up. Up next is three day lab and a unit test before final. Almost there!!!

Percent Yield & Limiting Reagents