Flame Test Lab

This lab was really colorful and that was fun to see. But the difference in colors also helped me see how the slight difference in wave frequency can change the color, and other factors so much. This lab was a much simpler lab than others we have done this year and it was definitely a lot less confusing. Another good thing about this lab was that it wasn't as time consuming as others and we could work  at a steady and relaxed pace.

Acids and Bases Unit Summary

Acids: taste sour and feel sticky; pH 0-6.9; turns litmus paper red
Bases: taste bitter and feel slippery; pH 8-14; turns litmus paper blue

Arrhenius Acids and Bases
acids: produce H+ ions in solution
bases: produce OH- ions in solution

Bronsted Lowery Acids and Bases
acids: produce/donate the H+ ion (proton) in the reaction
bases: accept the H+ ion (proton) in the reaction
conjugate base: produced by acids when they lose a proton
conjugate acid: produced by bases when they gain a proton

Acid Strength

• strong acids:ions completely disassociate in an aqueous solution 

• examples of strong acids: HClO4, HClO3, HCl, HBr, HI, HNO3, H2SO4

• largest Ka value is the strongest acid 

Strength of Salt

• Strong Acid + Strong Base = Neutral Salt
• Strong Acid + Weak  Base =  Acidic Salt
• Weak Acid + Strong Base = Basic  Salt
• Weak Acid + Weak Base = Neutral Salt

Ion Product of Water

• the ion produce of water is always 1.0*10^-14 at 25 degrees Celsius
• in an acidic solution, the H+>OH-
• in a basic solution, the H+<OH-
• in a neutral solution H+=OH-

Solving for pH and pOH for strong acids

Solving for pH of weak acid

Links
this link helps with ICE box problems:
practice for finding pH
help with Bronsted Lowery problems
Key Terms Quizlet

Unknown Molar Mass of an Acid Lab

The procedure for this lab was very similar to the percent acetic acid in vinegar lab. We had to titrate a known substance to calculate the molarity and use the mole ratio to find the molar mass of a different unknown substance when it was titrated. This was another tedious lab because we had to be very precise with our titrations (especially since it's based on percent error). The biggest problem we ran into was the fact that the unknown substance was taking a long time to dissolve. After we gathered our data, the basic approach to solving this lab was to find the Molarity of the NaOH, then use that (with a one to one mole ratio) to find the moles of unknown used. With the moles of unknown, when we divide the mass of the sample by the moles of the sample, we can solve for the molar mass of the unknown substance.

% Acetic Acid in Vinegar Titration lab

For this lab the main idea was to titrate the NaOH and then the vinegar to determine the Moralities of both. To titrate, we used KHP and the indicator phenolphthalein and added NaOH till the solution was a faint pink. When the solution turns faint pink, we know that all of the H+ has been used in the reaction.

The process itself was really tedious because we had to drop the NaOH slowly and make sure we got the exact point where the solution turned a faint pink. If the solution becomes a bright pink, that means we already missed the point of equilibrium. Even adding one drop past the light pink point turns the solution extremely pink so it is important to watch carefully. (Example of bright pink to the right and faint pink above)

Since this lab was based on percent error, it was important to do many trials so we would average to as close to the correct answer as possible. The first time we did it we got an extremely high percent error and that freaked us out and we were determined to be more precise for our next few trials.

Weekly Quiz

This week's quiz was a balance between really hard and decently easy. The first few problems I was confident with, but towards the end the test kept getting harder and harder. I can tell that I need to study the quadratic equation problems some more and figure out how to set them all up better. Otherwise, a lot of the questions I got wrong were misunderstandings and after studying and fixing those, I think I understand them now. What really helped me so far for this unit is the map that we got to find the concentrations of H+, OH- and pH and pOH. (inserted below). I think that road map sums up the basics of the pH portion.