Lesson 17-19

Lesson 17

In lesson 17 we learned that an indicator is molecular substance that changes color when it comes into contact with an acid or a base.

Acids and bases are corrosive. When pH is 7 it is neutral or pure water. Below 7 is an acid and above 7 is a base. This is a picture of the pH scale.

These pH solutions are classified by their colors you can observe. Acids and bases change the color of indicators.

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Practice Problem

3. It means that the substance is neutral. 

Lesson 18

In lesson 18 we learned about cabbage juice and its indicator colors. Cabbage Juice: Pink=acidic, Green=basic, Purple=neutral. Substances that add H+ (just one proton) to a solution are acids. Bases are substances that add OH- to a solution. Substances that don't add H+ or OH- to the solution are neutral.

The definitions of acids and bases has changed over time.

• Arrhenius Definition: An acid is any substance that adds hydrogen ion to solution. A base is any substance that adds hydroxide ion to a solution.
• Brønsted-Lowry Definition- An acid is a proton donor. A base is a proton acceptor.

The products of a reaction is always called a conjugate.

(Red) Base + Acid --> Conjugate Acid + Conjugate Base

(Purple) Acid + Base --> Conjugate Acid + Conjugate Base

Strong acids and strong bases dissociate completely into ions, while weak acids do not.

Practice Problem
1. A base is a substance that adds a OH- ion to a substance and an acid is a substance that adds a H+ ion to a substance. 

Lesson 19

Lesson 19 talked more about the pH scale. The pH scale is a logarithmic scale the describes the concentration of H+ ions. pH is related to H+ by the formula: pH=-log[H+] Water dissociates into H+ and OH- ions. Below is a picture of the pH scale and examples of substances that fit into each pH level.

[H+][OH-]=1.0x10^-14

Practice Problem
3A. 4
3B. 12

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Disappearing Spoon Chapters 5-7

These couple chapters focused on war and how warfare effected the periodic table. The first part focused on nitrogen and the attempts made to capture it. Fritz Haber was the scientist who finally achieve this goal. He was trying to create nitrogen bombs to use in WWI, even though this was illegal in the eyes of  the Hague Convention, but his findings ended up going into fertilizers instead. Eventually Haber's research helped save lives by rescuing those who were starving but he also killed a fair number with his bombs. The next part talked about Colorado! (Hooray a connection to life!) On Bartlett Mountain in Colorado, molybdenum was discovered. This is used to strengthen steel and because it could withstand extreme temperatures in was incredibly valuable to the war effort. In a bidding war over the right to this mountain Otis King won and became insanely wealthy by selling the molybdenum to Germany. That was the most exciting part for me because of the Colorado connection. WWI wasn't the only war where chemical warfare was used though. In the Republic of Congo, war broke out after the discovery of large deposits of  tantalum were discovered. This is a metal used in making cell phones in the 90s. The Congo government was so unstable that tibes fought for the money being made by selling the tantalum to huge cell phone companies. In this war about 5 million people died. Later on in the book it talked about Henry Moseley who managed to discover 4 elements before his early death. He did this by creating an electron gun that could find new elements in other elements essentially. When Moseley died scientists began using more math and calculations to find elements.Next the book moved into the Manhattan Project.  The US was trying to perform nuclear warfare by manipulating plutonium and uranium. Not enough would burn out and too much would cause mayhem. This period of time is also where women were brought in to the science world. The wives of scientists who worked on the Manhattan Project would tire through hours of calculations and ended up as an enormous help. Yay women! Then some other large chemical warfare discoveries were made from Berkley. Both berkelium and californium were discovered there and many experiments on alpha and beta particles took place. The research there was competing with Russia to the point where Joseph Stalin was interested in the research to benefit him and the Soviet Union in WWII but failed. I still am not a large fan of this book but there are some little details that i find interesting.

Lesson 16

Lesson 16
In this lesson we basically used all the knowledge we've gained from throughout the chapter to solve problems. We also did an activity where we had to try and figure out which solutions werer which by weighing them and accounting for the molar mass. The rest of our activity involved doing problems.

Practice Problem
2. There is more solute in the container.
7. The NaBr  would weigh the most because it has more solute than NaOH. The KCl weighs  half as much as the other two because, 500 mL is less than 1 L or 1000 mL.

Lesson 15

Lesson 15
The biggest thing we learned in lesson 15 was that you can use a hydrometer to test the molarity of the substance. I really don't think there was much else so there is a practice problem below!

Practice Problem

 









 

 



Lesson 13 and 14

Lesson 13

A solute is a substance dissolved in a solution. A solvent is the substance in which a solute dissolves. A saturated solution is a solution that contains the max amount of a solute for a given amount of solvent. Molecules move from areas of high concentration to areas of lower concentrations. We also learned about molarity. The equation used to find molarity is pictured below.

 

Practice Problem

 

8. B

 

Lesson 14

In lesson 14 we put our knowledge from the previous lesson into practice. We also learned that concentration does not depend on the density of size of a sample. When dealing with ionic compounds, take all the ions in the equation into account. We also learned that volume is always expressed in liters for the equation.

Practice Problem

 

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Disappearing Spoon-Chapters 3 and 4

Chapter three talks mostly about the formation of the periodic table. Who organized it, the different attempts to organize it and all who were involved. Dmitiri Mendeleev is the man given credit for the periodic table. He was able to draft a table and predict where new element would be when they were eventually discovered. However, Mendeleev couldn't have done it alone. The work of Bunsen and Lecoq de Boisbaudran helped immensly. Boisbaudean brought in the idea of gallium and then rethought his predictions afterbeing corrected by Mendeleev. This chapter also talked about the formation of lanthanides. A teen named Johann Friedrich Böttger convinced a crowd he could turn silver into gold and was promptly arrested for alchemy by the king. The king asked him to turn silver into gold for him however, Johann knew he couldn't because his joke with the crowd was fake but he somehow managed to convince the king to pair him with a porcelain maker. While the pair mined for the rok used to make porcelain they discovered copious amounts of a large, unidentified rock. Later on a geochemist was able to indiviually indentify these rocks, six of them became lanthanides. Chapter 4 was all about the elements in space. The topics included the formation of the earth's crust, information about Jupiter and possible theories about why dinosaurs went extinct. A popular theory is that stars heat hydrogen in their cores and fuse it with other hydrogen atoms, making helium. Then helium fuses with helium. This cycle repeats until iron is formed. Jupiter has been deemed a failed star instead of a planet and so many elements have strange affects there. Father and son Luis and Walter Alvarez began studying a limestone deposit which is dated back to when the dinosaurs are thought to have become extinct. What they learned is that basically when a large meteor hit the earth, very large amounts of iridium-rich dust would have arose. This dust would've blocked out sunlight and kept life from surviving. This chapter also talked about dating the earth but it was incredibly boring.

Lesson 12

In lesson 12 we learned that aspartame is much sweeter than fructose. The smaller the LD50 the more toxic it is. LD50 values are of limited use in determining the long term effects of a substance. Even if you don't reach the actual LD50 there could be very serious long term effects that are not accounted for in the LD50.

Practice Problem

The molar mass of C8H11NO3 s 169g.

 

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