Post 4 Acid and Base

We finished a second lab that involved a similar run as the first but we now had an unknown solid acid that we used. First we had to dissolve the solid in the water using heat before cooling it down and titrating it.

Here we placed it on a plate burner with a stirring rod.

Here it turns vibrant pink but the color begins to fade after awhile.

Post 3 Acid and Base

We did another vinegar lab that involved titrating KHP and vinegar samples using NaOH that turned the solution bright pink after mixing with phenolphthalein. It was the first time we used a buret, and it was difficult to control the drops, but regardless, it was a fun lab.
Here's the procedure:

 

1) Put on your splash-proof safety glasses, and keep them on throughout the lab.

2) Drain your buret into the waste beaker.

3) Rinse your buret with a small amount (several mL) of your NaOH solution, and drain into your waste beaker.

4) With the valve closed, add your NaOH solution until it is above the zero mark, and carefully drain until the meniscus is exactly at zero.

5) Obtain 0.5 – 0.8 gram of KHP, and record the mass to the nearest 0.001 g.

6) Transfer the KHP (without losing any) to the Erlenmeyer flask. Rinse the plastic tray with several mL of distilled water, and pour the rinse water into the Erlenmeyer. The goal is to transfer 100% of the KHP into the flask.

7) Add about 75 mL of water to the Erlenmeyer, and swirl to dissolve all of the KHP.

8) Add 2-3 drops of phenolphthalein.

9) Titrate the sample until a faint pink color remains, and record the volume of NaOH used to the nearest 0.1 mL.

10) Open up the vial with the blue cap. This vial contains commercial vinegar.

11) Pipet 10.00 mL of the vinegar into the Erlenmeyer flask. Dilute the volume to about 100 mL with distilled water, add two drops of phenolphthalein, and titrate with your NaOH solution. Record the volume of NaOH used.

12) If time permits, repeat steps 5-11.

13) Drain your buret, fill it with distilled water, and clean up you station.

Here's some websites that go over it.
khanacademy
chemwiki

Post 2 Acid and Base

Getting for the first quiz of this unit.
Acids [H+] and bases [OH-] together produce a salt and water. Acids produce conjugate bases and bases produces conjugate acids. These can then change through reactions.

When converting H+ to OH- use the equation H+ = Kw/ OH- in which Kw = 1.0 x 10^-14 and this equation can be used with OH- interchangeably

H+ to pH and OH- to pOH uses -log and going from pH to pOH would subtract 14.

Here's a link that provides information. mrwiggersci

Post 1 Acid and Base

We did another lab that involved the titration of vitamin c and iodine, which produced a clear color, and starch, which turned the solution blue to determine the concentration of vitamin c within different juices. Unsurprisingly, the grapefruit juice contained the most.

Post 3 Aqueous Solutions

Our latest unit includes both stoichiometry and molarity in calculations that, just like stoichiometry, convert volume (ml, L) using molarity (mol/L) into mols which are then converted into the new unit.
Here's a video that goes over it. youtube
Here's another website that goes over the step by step process of  calculating molarity using stoichiometry. yeahchemistry

Post 2 Aqueous Solutions

We have recently finished gathering the data for the murder investigation lab which involved double replacement chemical reactions, determining which reactions produced solids which when then used to determine that the mystery poison was silver carbonate. Here's a link to the lab. murder mystery lab

We discovered that the culprit was Mr.Green.
Here's a reminder on: double replacement youtube
                                   solubility rules chem 
                                   molarity occc , chemteam

Post 1 Aqueous Solutions

We did a lab that went over the concentration of stocks which involved diluting a stock of food colored water until the coloring had disappeared. Overall, it was a fun simple lab that got us into the new unit.

 Here's a website that goes over it. chemteam