Lablablab (5B)

Just an important reminder...

On that happy note...

Lab day!!



fact!

So today we created some surprisingly wild reactions.  In fact, there were 7.  Some more interesting than others... Anyways, the purpose of this lab was to view the different chemical reactions (keep those eyes open!), explain and then classify them.  Seems pretty simple, right?

So... fortunately, you probably don't have a bunsen burner at home, although I wouldn't be surprised if I found some copper (II) sulfate pentahydrate in your cupboards. haha jokes! but actually if you do, do not try to heat anything over your stove.  You might have a difficult time explaining that one to the insurance company.

The first thing you must remember to do is put on those fancy-schmancy goggles.  And do not take them off. Until the all-mighty one gives you permission.  Even if you have a dent in your forehead/nose/both.  Don't want to risk looking constantly surprised all week in the case that you accidently toast off your eyebrows.  And if you have long, flowing, luscious (pushing it?) hair like myself, then you better tie it up.  And then... (drumroll) You may begin!!

Reaction 1:

This reaction seemed neat at first, but the later reactions made it super lame, in retrospect.  In case you had already forgotten, this was the experiment where you held the copper wire of the bunsen burner flame for a few minutes while watching it turn silver (!) but then black.  I don't know if you noticed, but there were some pretty neat-o colour changes happening on that nail as it was adjusted over the heat. This was a synthesis reaction, as the copper nail was reacting with oxygen once the heat energy was added.

Reaction 2:

For this reaction, we put a shiny iron nail into a copper (II) sulfate solution, and left it in there for around 15min.  *Yawn* But when we came back at the end, what did we find? Magic you say? I think not.  What we saw was a single replacement reaction, as the iron bumped out the copper in the solution.  That is why the nail had bits of metal stripping off like bark on a tree.  We also viewed a bit of a colour change.

Reaction 3:

This reaction used the previously mentioned copper (II) sulfate pentahydrate (that blue powdery stuff).  We placed it in a test tube, and then held it over the bunsen burner.  The book warned us to be sure to angle the test tube towards someone you dislike. KIDDING. It actually specifically mentioned that we faced it away from people... How unfortunate.  Funnily enough, the test tube clamp I used heated up during this reaction and I ended up using crucible tongs to hold the test tube clamp which held the test tube.  It was a precarious situation.  I would not recommend doing what I did.
Anyways, we then saved the remaining blue (but now whitish) stuff for reaction 4.  This was an example of a decomposition reaction.

Reaction 4:

Once the blue stuff from reaction 3 had cooled, we were allowed to add water to it.  So, this was a synthesis reaction.  This caused the test tube contents to return to a blue colour, and after a while, it appeared slightly greenish.  Made me think of mermaid tails. Which made me think of sushi... Cut me some slack it was right before lunch...

Reaction 5:

This was sort of neat.  For this reaction, we added a calcium chloride solution to a sodium carbonate solution.  They were both clear substances, so I thought this was going to be some lame-o reaction where there were bubbles for like 2 seconds and then it would be over... But I was pleasantly surprised! We observed a double replacement reaction.  When the two solutions were combined, a solid (precipitate) was formed!  weeeeeeeooooooooo.  And it wasn't even clear!  So that means colour was also added when the precipitate was created :)

Reaction 6:
Not gonna lie, when I saw mossy zinc on the material list I caught the giggles.

Seriously? Did that picture not enter your mind?

Awkward.  Anyways, turned out the mossy zinc didn't look anything like that.  Boy was I caught off-guard...
When hydrochloric acid was added to the solution, we saw bubbles!! And they just kept going... For like... well actually until we poured it out haha. Someone would have been excited...


This was another example of a single replacement reaction.

Reaction 7:

COOLEST. REACTION. EVER.  Hydrogen peroxide + manganese (IV) oxide? Genius.  And an environmentally friendly hand-warmer. ;) 

When the black powder was added to the solution, the reaction was immediate.  Smoke (yes that super-cool misty-type smoke that they use on TV) was formed.  The bubbles created OWNED those from reaction 6.  And that black powder? It became this nasty black viscous substance that kept creating these giant bubbles at the top of the test tube.  And the amount of powder I added was so tiny that I thought nothing would happen! Glad to be wrong, for once.  The coolest part of this experiment was definitely once we put the glowing splint over the test tube AND IT CAUGHT FIRE!! OVER AND OVER AGAIN!! UNTIL IT WAS TIME TO START CLEANING UP... Next time I go on a camping trip (ha who am I kidding... such a city slicker :P) I'm going to borrow some of that stuff.  Forget flashlights.  This is so much cooler.
I think it's safe to say I know which element was involved in this reaction.

Worst part of this lab? Trying to get that stupid blue stuff out the the test tube! That was 10min of my life I will never get back.  It's funny, because Ms. Chen warned me beforehand that it would be a pain getting it out.  I thought HA YEAH RIGHT.  I sure paid for that one.

I hope my excited rambling didn't bore you to tears... But here's something to make up for it!!

Shish kabobs!

Heatherwantsdinner.
Hasta la vista!

REACTIVITY VIRTUAL LAB

Hey guys, today we went to the computer LAB to do a LAB. HA-HA (Lame joke of the day) No? Okay... /weeps in the corner


We took a little breather from balancing equations and did a virtual lab about reactivity! The lab was based on single replacement reactions and the reactivity of metals. From doing this lab, we learned that in order to have a single replacement reaction, a more active metal will always replace the anions of a less active metal.To determine the reactivity of a metal, you can compare them through different metal ions with same negative ions. Now, our "Activity Series" sheet comes in handy.

(listed from greatest reactivity to least)

LET'S RECALL:
(formula for single replacement)

A + BC --> AC + B


A = more reactive metal
B = less reactive metal
C = any negative ion that remains the same throughout experiment


So let's say that aluminum is added to copper (II) chloride. By checking our activity series chart, we can see that aluminum is surely more reactive than copper. Hurray! There is a single replacement reaction, so we can finish the equation. Remember to balance!


2Al(s) + 3CuCl2(aq) --> 2AlCl3(aq) + 3Cu(s)


On the other hand, if copper was to be reacted with aluminum chloride, then there will be no reaction since copper is less reactive than aluminum.


Throughout the lab, we did a series of activities where we observed the reactions (if any) of different metals by placing them into each solution. Note that each solution contains the same negative ions. This means that the reaction of the metal is purely based upon the different metal ions. From this, we can tell if a metal is active or not. There will be no reaction if the metal that is being placed in the solution is less reactive (or the same) than the one already in the solution.

Here, magnesium is placed into four different solutions. We see that a reaction has occured when the colour of the metal or its shape has been changed from its original form. From trying out all of these activities, we have found out that magnesium is the most reactive out of all of the ones that are stated throughout the lab. You can also check by referring back to the "Activity Series" chart!


Therefore, by using different solutions with the same non-metals, we can find out the reactivity of each metal. And from this information, we can predict whether or not that metal would react in the future.


P.S:
Did you know, the Statue of Liberty was made out of copper? Hmm why is that? Why not iron..? ;)


*HINT HINT* Look at your activity series sheet/chart.

If you would like to try out this lab, here is the link! :)
http://mrpalermo.com/Virtual_Lab_Activity_Series.html

Type of Reactions PART DEUX

Double Replacement
 
What is double replacement?
It's a reaction with two ionic compounds usually in a solution. It's like a switch partners dance! The ions switch partners. The positive ions switch places.
 
General Formula: 
AB + CD ---> CB + AD
 

In this case, the positive ion (or A) is the brunette girl, the brown-haired guy is B, the blonde girl is the other positive ion (C), and the blonde guy is D. The girls = positive ions. The guys = negative ions. In a double replacement reaction, the positive ions, in this case the two girls, would switch positions and will therefore have different partners. Now, the brunette girl is paired up with the blonde guy (AD), and the blonde girl with the brunette (CB).
 
For ex:
Na2CO3 + CaCl2 ---> CaCO3 + 2NaCl
(remember to balance your equations!) 


BUT how can we find out if the double replacement even occurs???
During the reaction, if the reactants changes its state, then there is a reaction occurring. So if a precipitate (formation of a solid in a solution) forms, then a double replacement reaction occurs. AND IF there is no change of state then obviously that means that there is no reaction.
 
REMEMBER to use your "Table of Solubilities"!! This will determine the states - (s) or (aq)
 
In case you don't know how to use this "Table of Solubilities", i'll just do a little review on that!
 
First: Find the negative ion on the left side of the column.
Second: Look for the positive ion on the second column.
Third: Follow its presence or absense to the word "soluble" or "not soluble''
Fourth: If it's soluble, the compound = aq
Fifth: If it's not soluble, the compound = s
 
Net Ionic Equations
 
??? What is this????
When you have a precipitation that occurs, we write a net ionic equation for the reaction in ionic form to indicate the ionic components that exists in a solution.
(aq) ions that are the same on both sides gets cancelled!
 
For ex:
2Na3Po4(aq) + 3Ca(NO3)2(aq) ---> 6NANo3(aq) + Ca3(PO4)2(s)
the aqueous ions that are equal are cancelled, leaving the ions that forms the precipitate.
Net Equation
3Ca2+(aq) + 2PO43-(aq) ---> Ca3(PO4)2(s)
 
Combustion
 
A combustion is a reaction when a burner in the air is involved. The reactants are the chemical to be burned and the oygen that it reacts with. Oxygen atoms end up combined with more than one type of atom as products.
 
General Formula:
AB + O2 ---> AO + BO
 

 
For ex:
C4H8 + 6O2 ---> 4CO2 + 4H2O
 
Neutralization
 
This is a special DR reaction when acids react with bases to produce water and an ionic salt as a product.
The acids have an H+ as the positive ion and the bases have OH- as the negative ion. Both should be (aw) solutions.
 
General Formula:
HA + BOH ---> H2O + BA
 

 
For ex:
2HBr(aq) + Sr(OH)2(aq) ---> SrBr2(aq) + 2H2O(l)
 
 
 
 
~~~~~~
 
 
 

And that's it!!! 
 
- Melody

Types of Reactions

Aloha guys! 


As you guys should remember from last year; we learned about the six different types of reactions! There is synthesis, decomposition, single replacement, double replacement, combustion, and neutralization.
But if you're like me and you forgot everything there is to know about these reactions, here's a little review on synthesis & decomposition:

A: Synthesis

- reaction that combines two or more reactants to form one product.

haha that photo just tells all of us... Don't eat too much worms, or else we'll become like that bird on the product side.


GENERAL FORMULA: A + B  → AB

So here are some examples:
ex. 1Ca + 1Cl2 → 1CaCl2

ex. 2Al + 3Cl2 → 2AlCl3

B: Decomposition 

- reaction that breaks down one reactant into two or more products.

aww look at that cute little chicky :) ..... no I'm sorry but that is actually a pretty ugly chick .. .BUT ANYWAYS, back to decomposition.

GENERAL FORMULA: BC → B + C

Here are some examples of decomposition:
ex. 1CaCO3 →  1CaO + 1CO2

ex. 1CuSO4 →  1CaO + 1 CO2
ex. 1CaCO3 · 1H2O  →  1CuSO4 + 5H2O


C: SINGLE REPLACEMENT
(metal)
- metals (+ ions) replaces the other metal

Joe, in the green, is the positive ion who replaces the other guy Frank (who is also a positive 
ion).Joe ends up being with Mary, the negative ion, while poor Frank is left alone and 
divorced... or dumped...


GENERAL FORMULA: A + BC → AC + B


Examples examples examples:
ex. Mg + 2KCl → MgCl2 + K2
ex. 2Al + 3BaO  → Al2O3 + 3Ba


(non-metal)



So this is basically the same thing, but instead of Joe ending up with Mary, he ends up with Frank...... now how awkward is that. 


GENERAL FORMULA: A + BC → BA + C


More of les examples:
ex. 2Cl2 + 2MgO → 2MgCl2 + O2
ex. 3S + 2FeI3 → Fe2S3 + 3I2



I just realized that both my pictures are of chickens or birds of somesort.... welll HERE COMES THE CAT





Well I hope you now remember what synthesis and decomposition is.
Stay tuned for Melody's continuation of the rest of the reactions!


xoxo,
Kimberly Girl

Balancing For Dummies

HAHAHAHAHAH I FOUND ANOTHER ONE!!



YESSSS.
well now that we have that out of our system....


heh.
We are officially ready to reveiw our topic from last class! Phew so happy I actually completely understand balancing haha.
So here's an example of a synthesis reaction:

C2 + O2  -->  CO2

now wait a second... how is it possible that you started off with 2 carbon atoms and 2 oxygen atoms and you ended up with 1 carbon and 2 oxygen? did that other carbon just magically disappear?

Nah bro.  It's still there.
The equation showed above was a skeleton equation.  That is, it was unbalanced.  So you're new life purpose is to balance that equation. 

The way I find easiest to keep track of how many atoms of each element are on each side of the equation is called taking "attendance." 

C2 + O2                   -->               CO2
atoms of C: 2                               atoms of C: 1
atoms of O: 2                               atoms of O: 2

So as you can see, there needs to be another carbon on the right side of this equation.

C2 + O2                -->                  2CO2
atoms of C: 2                               atoms of C: 1   2
atoms of O: 2                              atoms of O: 2   4

But now there are more oxygen on the right side than the left... Now we gotta go back and adjust the amount of oxygen on the left side so there's an equal amount.

C2    +    2O2                 -->             2CO2
atoms of C: 2                            atoms of C: 1 2
atoms of O: 2 4                         atoms of O: 2 4

Now wouldja look at that! There are 2 atoms of carbon on each side, and 4 atoms of oxygen per side!! But we are not done yet...

Don't forget to put 1 in as the coefficient if there is no other number there, just for clarity.  Otherwise Ms Chen might think you just didn't finish the question or something.

1C2     +   2O2            -->               2CO2
atoms of C: 2                           atoms of C: 1 2
atoms of O: 2 4                        atoms of O: 2 4

Et Voila!! How magical is that?!



I once tried taking a nap with my textbook  under my pillow.  Apparently that cat and I think similarly.


Until we meet again...          *tips imaginary hat*
Heather

Molar Volume of a Gas at STP

How was your winter break guys? Yeah, I miss it too. Oh well, all we can do now is slug through school and wait for spring break to come!! But we all love chemistry (!) so it will be okay. :)

here's another picture to all the other
cat pictures we have on this amazing blog

So last class we learned about STP, you're probably thinking "What in the name of monkeyballs is STP?!" Well I'll tell you what STP is, it stands for Standard Temperature & Pressure.

Here are some notes about what we learned last class:

• Gases expand when the temperature rises and contract (change volume) when cooled all due to changes in the temperature and pressure.
• We have a standard condition to compare volume of gasses called STP (Standard Temperature and Pressure).
• STP = 1 atmosphere of pressure and a temperature of 0°C or 273.15K
• At STP 1 mole of gas occupies 22.4L

Since we know that 1 mole ALWAYS occupies 22.4L at STP, we can create the conversion factors:
22.4L of gas               or             1 mole of gas
1 mole of gas                               22.4L of gas

This is VERY useful!! Make sure to add this into your mole map!


For example, calculate the volume occupied by 5.3g of carbonate at STP.
Step 1: Find the molar mass of carbonate (CO₃).
(1x12.0) + (3x16.0) = 60.0g
Step 2: Convert into moles.
5.3g x (1 mol / 60.0g) = 0.08833 moles
Step 3: Calculate the volume using the conversion factors.
(22.4L / 1 mole) x (0.08833 mole) = 1.9787L

∴Volume occupied by 5.3g of ammonia at STP is 2.0L

And voilà! Now you have learned all about STP and how to use it in an equation!
Hope this blog helps you guys and remember, quiz on Thursday so review your moles!

Love, Kimberly:)

Diluting Solutions!!

First and foremost, we, the beryllium chemists, would like to welcome you back from the (never-long-enough) winterbreak! It still feels kind of hazy being the first week back...

Today, we will be talking about diluting solutions to prepare in workable solutions.

RECALL:
solution: homogeneous mixture where one substance is dissolved in another
solute: the chemical/substance being dissolved in the solvent
solvent: the substance that does the dissolving


Have you ever had a juice that said 100% juice or 100% concentration? (Concentration: amount of solute that exists in a given volume of solution)

Well that means it is consisted of a high concentration of the natural juice, without any other added liquids (besides what is stated). It will also have a stronger taste. In other words, it is made up of mostly the natural juice - which is the solute in this case - that is dissolved in this solution.
If we add water (solvent) into the concentration, it will dilute, and therefore will create a lower concentration of the juice because there is less juice that is being dissolved with the added water.
For example, adding large amounts of water would decrease (or weaken) the amount of concentrated juice. This is the process of dilution.

It is important to note that the number of moles of the solute always remains the same. The only difference is that the volume increases and consists of more water (solvent) in the less concentrated solution.
Thus,

moles of solute before = moles of solute after

In terms of molarity and volume..

­M­_1­L₁ = M₂L₂

_{The subscript 1 represents the "before" and the suscript 2 represents "after"}

Eg. A 0.230M HCl solution is diluted to a final volume of 2.50L and a concentration of 0.100 M. How would you make up the diluted solution?

Plug in the information into the equation:

(0.230M)(L₁₎ = (0.100M)(2.50L)

L₁ = (0.100M)(2.50L)/0.230M

    = 1.09L

You would take 1.09L of the concentrated HCl and add 1.41L of the solvent (2.50 - 1.09) to make up a total of 2.50L of 0.100M HCl.

Eg. 120.0 mL of 0.150M HCl is added to 200.0 mL of water. What's the new molarity?

Convert millilitres to litres.

(0.150M)(0.1200L)/ 0.3200L = new molarity

M2 = 0.0562M

Always remember to round to the desired sig figs!

Here's a video if you need further help or practice!
Goodluck! :)