Finals. ;__;

Ewww. Finals. What every student dreads at the end of the year. If this was elementary or middle school, we would be having parties all day this week, but no, high school is evil and we have to have finals. I am such a retard. D:

I have all A's in all my classes... except Jackson. AUGH.
I got a 50% on my Cyrano essay final and it dropped my grade to an 86.9%. Now the only things I have left to raise my grade to a borderline A- are some last minute quizzes, extra credit, and THE FINAL. But the worst part is, I never get good grades on my finals. I always rely on my high grade to shield me from the drop in my percentage after bombing one. LOL, THE IRONY

So yeah. I liked Joy Luck Club, but I am just really anxious for the essay. I hope I get an A and Jackson will be nice and if I get a B+ he'll raise it to an A-. T_T Then my mom won't be all "WTF" at me. :C

Mini Project #3: Homemade Ice Cream

To demonstrate the properties of lowering the freezing point of something, we made homemade ice cream in class today. It was really yummy :) (although there was water and salt and ice everywhere! x.x)



Photocredit: Theresa Anselmo

To make our homemade ice cream, we put 1 cup of milk into a ziploc baggie and added two tablespoons of sugar and some vanilla extract. Then we sealed it off and put it into a bigger ziploc bag with lots of ice and 1/3 cup of salt in it, and sealed that too. After we shook it for about 5 minutes, the milk would begin to solidify and it would turn into some delicious ice cream :)

But how does this work? When the salt comes in contact with the ice, the salt lowers the melting point of the ice, making it really really cold, allowing the ice cream to solidify.

Mini Project #2: Frozen Water Balloon

Instead of being boring and just making a balloon filled with water, I decided to throw it in the freezer for fun. What did I get?

This.



Photocredit: Myself

It's a frozen water balloon! I thought the rubber would crack from the ice forming (think frostbite), but rubber is extremely flexible and didn't crack at all. It's structure allows it to stretch itself and fit to almost anything!

How to make a frozen water balloon:
1. Fill a balloon with water
2. Tie the balloon off
3. Put the balloon in the freezer for one day
4. Voila! Your very own lethal cool frozen water balloon!

Chem Standard Post

ChemStd 5a: Students know the observable properties of acids, bases, and salts.



Acids and bases are substances that donate and receive protons. They are rated based on a pH scale from 0 to 14.

Acids are proton donating substances that give away protons when aqueous. Examples of some acids include hydrogen chloride (HCl), carbonic acid (H2CO3), and citric acid in lemons and oranges.

Some properties of acids:

they are corrosive

they taste sour

they neutralize bases

pH is less than 7

blue to red, acid

Bases are substances that receive protons, namely from acids. Bases can be found in many cleaning products like soap. Examples of bases include ammonia (NH4), caustic soda (NaOH), and milk.

Some properties of bases:

they are corrosive

they feel soapy

they taste sour

have pH more than 7

red to blue, baseroo



Salts are ionic compounds that result when you mix an acid and a base together. It's composed of a metal and a nonmetal cation and anion. When you put salts in water they dissolve and separate into their ions. Common table salt (NaCl) is the best known example of a salt.

Some properties of salts:

they are ionic

crystallized structure

dissolve in water

conduct electrical current in water

high melting point

brittle

Mills Canyon Field Trip

I didn't go on the field trip on Thursday. :D School was the same just as usual and all xD


View Mills Canyon in a larger map

This is the path to and through Mills Canyon. Pictures credit to Mr. Olson.

Mini-Project #1: Invisible Ink

Materials:
# Half a lemon
# Water
# Spoon
# Bowl
# Cotton Bud (Swab, Ball)
# White Paper
# Lamp or other light bulb

Procedure:

1. Squeeze some lemon juice into the bowl and add a few drops of water.
2. Mix the water and lemon juice with the spoon.
3. Dip the cotton bud into the mixture and write a message onto the white paper.
4. Wait for the juice to dry so it becomes completely invisible.
5. When you are ready to read your secret message, heat the paper by holding it close to a light bulb.

Safety Precautions:
# Safety first, goggles on!
The acid from the lemon can burn your eyes and cuts on your skin.

Scientific Principles:
Since lemon juice is acidic and also organic, an oxidation reaction occurs when heat is applied and the words will turn brown. Any other acidic substances will work as well. Theresa and I used vinegar as a substitute (since squeezing lemons is rather dangerous xD)


Me and Theresa. Photocredit to Marcia Lee!

Well apparently our project half-failed because we didn't have a lightbulb to use as a light source, and the fire was a little too dangerous xD! The message reads "HI! WE <3 CHEM!"

iProposeWe

How to Make Glow-in-the-Dark Slime
How to Make Glow-in-the-Dark Slime (with similar instructions)

Materials needed:

Elmer's glue gel or 4% polyvinyl alcohol solution

4% (saturated) borax solution

phosphorescent zinc sulfide (ZnS) or glowing paint

measuring cups/spoons

bowl or ziploc baggie

spoon (optional)

Procedure:
1. Make a 4% polyvinyl alcohol solution. Another substitution is one part regular school glue, mixed with three parts water.
2. Mix zinc sulfide into the polyvinyl alcohol solution (approx. 0.6ml ZnS per 30ml of solution). Or, use glow-in-the-dark paint found at arts and crafts stores.
3. Make a 4% saturated borax solution.
4. Mix 3 parts of the PVA or glue gel solution with 1 part borax solution, and slowly mix inside a sealed baggie with a spoon or with your hands.

Safety Precautions:

Don't eat or inhale the slime or any of the ingredients

Always wash your hands after using the slime

Scientific Principles:
1. Slime is made up of polymers.
2. The borax acts to connect the glue molecules, creating chemical polymers, which makes slime.
3. Zinc sulfide has a special physical chemical property of glowing in the dark.

Measuring Air

it would make sense that air weighs nothing... but apparently it does!

the molar mass of air, as we discovered this week, is about 30 grams per mole of air. so air has weight. whaaat.

we made a vacuum in a syringe (which was really hard to pull out D:) and then weighed it on a scale which kept going up and down :C. Then we put the air back in the syringe and weight it again. then we used lots of equations and stuff and calculated the number of moles of air in the syringe and how much it weighed. that's how we got the molar mass of air. yay! we kinda solved it like this but i think it was less complicated.

Japantown Field Trip

whee.

today we went to Japantown (or 日本町）. we did this scavenger hunt with lots of first year Japanese students. We walked around all day today and looked at lots of different cultural items in Japan. We had lunch at some place called Sapporo-ya and they had some really yummy ramen. Then we went and got lots of crepes for dessert. I got a chocolate gelato crepe. :3 Theresa had some really expensive ice cream もち.

I wanted to go to the Pikapika photo booth stalls but we didn't have enough time to go, and we had to go back at like 1:30 (which is super early!) and now because of that I'm sitting here typing up this blog about Nihon Machi. :o

David Webb, The Vacuum Master

There was this guest presenter named David Webb who came on Tuesday to show us some really cool demos using air pressure. He had this vacuum chamber which used a pump to pump out air using air pressure (not sucking!) and really funny things would happen to things inside the airless chamber (vacuum)!

He did lots of fun stuff like putting a feather and a metal washer into the vacuum and showing us how they fell at the same time in it (because the feather doesn't encounter wind resistance). Then he magically made marshmallows bigger, like this!

It was pretty fun that day. Although I have to wonder what the American Vacuum Society is o_o.

Gay-Lussac's Law

This guy discovered the law that air pressure increases when temperature increases. We did this lab on Thursday when we dumped a test tube full of air and a black pressure gauge into increasingly hotter liquid water, and then hot oil @_@

Then we made this graph and we found out the absolute zero temperature is around -300 degrees celsius! that's super cooooooooold.

MC Delta T

And it's M, C, Delta T!

That's calorimetry dawg.

MC Delta T is a formula that calculates the specific heat of a substance. It's used in calorimetry.

Q = MCDeltaT, where Q is the heat energy in joules/calories, M is the mass in grams, C is the specific heat in calories or joules per Celsius gram, and Delta T is the change in temperature of the substance.

Here's a calorimetry sample problem.

Elephant toothpaste, desu

Today Mr. Olson did the elephant toothpaste experiment. :3

He put some hydrogen peroxide and dishwashing soap together, and he said it was supposed to react really slowly and finish reacting after a couple days. But when he put a catalyst in, potassium iodide, the solution suddenly turned yellow, and bubbled right over the cylinder :o

It was really hot and steamy yellow puffy stuff!

Like this!

Sodium Carbonate, Hydrochloric Acid, and YOU

We made this white powdery stuff react with hydrochloric acid in a lab on Tuesday that made water, salt, and carbon dioxide gas. We calculated how much carbon dioxide gas and salt we would theoretically have if three grams of sodium carbonate was added, using the grams to moles to moles to grams conversion ratio thingy. Afterwards, we added them together, and there were bubbles! Then we boiled all the water away (with dangerous matches) and we had some salt left. :O

Kinda like this.

Magnesium Oxidatioooooooooooooooon

On Tuesday, we blew up the lab. :D

Just kidding, but we made some magnesium react with oxygen to form some white chalkey stuff called magnesium oxide! We didn't make it react really fast like the picture, but we stuffed some magnesium into a crucible and heated it up with a bunsen burner using matches (which is really really scary!) D:

Then afterwards we measured it and the magnesium oxide was supposed to weigh 0.60 grams when we put in 0.36 grams of magnesium. But we were wrong.

On a side note I want to make some ice cream and elephant toothpaste at the end of the year. :<

THE FIVE REACTIONS OF CHEMISTRY

HAR HAR HAR.

There are five different reaction types. They are:

1. Synthesis: Two elements combining into a compound.



2. Decomposition: A compound that reacts to break down into its basic elements.



3. Single Replacement: A compound and a pure element in the reactant side will switch atoms, in the pattern metal/H with metal/H or halogens with halogens. AB + X -> AX + B



4. Double Replacement: Two or more compounds in the reactant side swap ions, sometimes a precipitate is formed. AB + XY -> AY + XB



5. Combustion: A reaction where hydrogen, oxygen, and carbon are always part of the reactants and carbon dioxide, water, and heat are the products. The reaction is also an exothermic reaction.

Stoichiomewhawha

Stoichiometry is the process of making and balancing chemical equations.

Here we have a simple chemical reaction, the creation of hydrogen chloride from reacting hydrogen and chloride.



In the chemical reaction, one hydrogen atom and one chloride atom react to form ions, which attract each other to form the ionic molecule hydrogen chloride. But since there are two hydrogen atoms in hydrogen gas and two chlorine atoms in chlorine gas, the product of HCL must be doubled in order to be balanced. This is the science of stoichiometry.

Reactions!

Theresa is panicking nearby trying to finish her Japanese project. :D So excuse me if this post happens to be filled with nonsensical nonsense.

Chemical reactions are basically the rearrangement of atoms and molecules into new compounds. Heat, bubbles, color changes, property changes, and precipitates (insoluble solild) are all signs of chemical reactions. Chemical reactions happen all around us, even inside our bodies when we breath, eat, and do anything.

Balancing these chemical reactions to have the same amount of atoms on both sides is kind of hard. D: It's kind of like algebra... kinda.

Also I got a 104% on my Solutions and pH test. Yay! :D

pH and PMSing

Potential Hydrogen and Periodic Male Stupidity.

Although they sound similar, they are really two very different things.

pH is a measure of how many [H+] ions are present in a solution. Its counterpart is the [OH-] ion, or the hydroxide ion. Hydrogen ions are generated when acids are dissolved in water, separating its Hydrogens from the anion. Once inside the solution, the hydrogen ions will react with water molecules to form Hydronium ions (H3O).

If a strong base is dumped into water instead, the [OH-] ions that separate will react with [H+] ions present in the water to form H2O molecules, thereby increasing the pH of the solution.

Making Solutions

In chemistry, we're learning about solutions. In a lab last week we made solutions of some liquids and solids. We calculated exactly how many grams of cobalt chloride we should add to a solution of water. After dissolving it in water, we took it to a spectrometer where we measured how much light it absorbed to determine how accurate our measurements were. Our group turned out to be off in the first measurement, but right-on in the second solution measurement of potassium permanganate.

It goes to show how much accuracy can affect science!

Like Dissolves Like

Dissolving is the process where a substance (also called the solute) is broken down in another substance (called the solvent). It forms a homogeneous solution which will never settle. In the case of water, a polar solvent (the universal solvent), it can dissolve other polar compounds and ionic compounds. Likewise, nonpolar solvents can dissolve nonpolar solutes. This principle is called 'like dissolves like', where similar compounds will dissolve other similar compounds.

Below, salt, an ionic solute, is being dissolved by water, the polar solvent.



Alka-seltzer is a solute which also dissolves in water.