Molar Volume Lab

Hello again!
We did a Molar Volume Lab before the Winter Break and it contained a sink full of water, a graduated cyliner, and a lighter with a substance called Butane which is known for its combustive traits. But in this lab we measured how much Butane is consumed  underwater on top of a graduated cylinder. This sets us up with our estimated "STP" or Standard Temperature and Pressure, which is 22.4. None of our classmates were near to the number but one of the groups recorded a 24.2, which was SATP.

Multi-Step Conversions

  Sometimes, there will be cases where you will be given information that you would have to use in order to make numerous conversions. Here are some examples:

EXAMPLE:

12.5 grams of Hydrogen (H2) are placed in a balloon at STP (Standard Temperature and Pressure = 0º C & 101.3 kPa). Determine it's volume.

1. First, use molar mass as your conversion factor and cancel accordingly.

-> 12.5 g of H2    x    1 mol     
                               2.0 g*


*The mass in grams is 2.0 because there are hydrogen is diatomic.

2. Next, use molar volume as your conversion factor and cancel accordingly.

-> 12.5 g of H2    x    1 mol    x    22.4 L
                               2.0 g           1 mol

3. Alter your answer to have the appropriate number of significant digits.

-> There are 1.4 x 10² Liters in 12.5 grams of Hydrogen.


   There will be other instances where they ask you for more conversions such as grams to atoms or liters to molecules. The most important thing to do is to first recognize what you have and what your answer's units should be. From there, you can decide on you conversion factors. Here are some of them:

Molar Volume (of all gases @ STP):
22.4 L / 1 mol

Molar Volume (of all gases @ SATP-> Standard Ambient Temperature & Pressure):
24.8 L / 1 mol


Molar Mass:
grams (g) / 1 mol


Avogadro's Number:

6.02 x 10²³ molecules or atoms or fundamental units / 1 mol

  Here are some links to help you out as well:
http://www.youtube.com/watch?v=tS9l-OxucQU
http://www.youtube.com/watch?v=AsqEkF7hcII&feature=related
http://www.youtube.com/watch?v=8TkY36qB1f0

Moles to Molecules

Remember Avogardo's number?

6.02 x 10^23

Well in this lesson we learned about how to convert Moles into Molecules

We did examples like:
-How many atoms are there in 1.5 mol of Iron?

We start off like this

1.5mol x __________

Since we have to cancel out moles, to cross multiply out the mols, you have to put 1 mol (usually) on the bottom

1.5mol x __________
                  1 mol

And remember Avogardo's number? Well plug it in the top!

1.5mol x 6.02 x 10^23 molecules
                         1 mol

So since the moles cancel out, we multiply 1.5 mol and Avogardo's number and we get....

1.5mol x 6.02 x 10^23 molecules = 9.0 x 10^23

                         1 mol

Well thats all for today guys! 

Moles to Volume Conversions

  Some important facts to remember when converting from moles to volume are:

-At a specific pressure and temperature, 1 mol of gas occupies the same volume.

-> At 0º C and 101.3 kPa, 1 mol = 22.4 L

  Therefore, the number of atoms there are of a gas is irrelevant in converting as every gas will occupy the same volume. STP, or Standard Temperature and Pressure is another more convenient way to refer to 0ºC & 101.3 kPa. At STP, 22.4 L/mol is molar volume.

EXAMPLE:

  How many litres exist in 3.5 mol of Oxygen (O2)?

1. Write out what you know and what you want to find out.

2.5 mol   x   22.4 L   =  ?  L

     1 mol

2. Cancel out what you can and solve accordingly.

2.5 mol   x   22.4 L   =   56 L

  1 mol

*ALWAYS REMEMBER TO PUT THE APPROPRIATE NUMBER OF SIGNIFICANT DIGITS

EXAMPLE:

  Chlorine (Cl2) occupies 240 mL. How many moles exist?

1. Convert mL to L.

240 mL   x   1 L   =   0.240 L

 1000 mL

2. Write what you know and what you want to find out.

0.240 L   x   1 mol   =   ? mol

   22.4 L

3. Cancel out what you can and solve accordingly.

0.240 L   x   1 mol   = 0.0107 mol

22.4 L

*ALWAYS REMEMBER TO PUT THE APPROPRIATE NUMBER OF SIGNIFICANT DIGITS

http://www.youtube.com/watch?v=AHqNiEwcXiE

Avagadro's Number

-Atoms and molecules are extremely small.
-Macroscopic objects contains too many to count of weigh individually.
-Amedo Avagardo proposed that the number of the atoms in 12.00000g of carbon be equal to a constant(this is equal to 1 mol of carbon)
-This value is now called Avogadro's number and forms the basis of all quantative chemistry.
Avogadros Number
6.02x10e23      atoms over mol


http://sciencelost.com/images/mole2.jpg
http://ny-image2.etsy.com/il_fullxfull.95300322.jpg

Molar Mass & Molar Conversions

  Molar Mass can be defined as the mass in grams(g)of 1 mole in a substance. Therefore, it would be measured with the units grams per mole (g/mol). This number can be determined by looking at the atomic mass on the periodic table as the atomic weight of an element in grams is one mole of that element.

Molar Mass of Compounds
 
The molar mass of compounds is determined by adding the mass of all the atoms in the compound. Here are some steps to follow:


1. Find the individual masses of each element.

EXAMPLE:
H2SO4 -> Hydrogen: 1.0 amu, Sulfur: 32.1 amu, Oxygen: 16.0 amu
H2SO4 -> 1.0 + 32.1 + 16.0

2. Check to see if the number of atoms of each element correspond with the formula. Add any necessary changes.

EXAMPLE:
H2SO4 -> 2(1.0) + (32.1) + 4(16.0)
H2SO4 -> 2.0 + 32.1 + 64.0


3. Add all masses together with proper significant digits and units.


EXAMPLE:
H2SO4 -> 98.1 g/mol
H2SO4 -> 98 g/mol

  There may be cases where you may have to convert between moles and mass. In these cases, use molar mass as your conversion factor.

EXAMPLE:
  Determine the mass(g) in 3 mol of Oxygen.

1. Write out what you know, and what you want to find out.

3 mol of O    x          3(16.0) g          = ? g
                                 1 mol

2. Cancel out anything that you can.

3 mol of O    x          48 g                =? g
                              1 mol

3. Do any more calculations accordingly and write answer with proper significant digits and units.

 3(48g)     = 114 g of O
     1 

  You can do the same when finding the number of moles in a certain number of grams; just place the units in the correct part of an equation and repeat the steps!

http://www.youtube.com/watch?v=m8JYa5DZv2o&feature=related 

LAB TIME!!!

Today we did an experiment dealing with hydrates!

What are hydrates you ask? Well they are simply Compounds that are bonded along with H20 (water)

Ok, so in the lab we are comparing the hydrate and anhydrates of colbalt chloride hydrate

We started the lab by...of course safety equipment.

Then we did the lab (which was basically using the bunsen burner to evaporate the water inside the colbalt hydrate.

Things I noticed in the lab...
1) The hydrate at the start was crimson, and during the evaporation part, it started bubbling and turned a royal blue, then as we kept on evaporating, it turned into a really light blue.

2) Some of my peers also had "plaque", as my teacher said. and it was due to overheating???? not sure

3) After we evaporated the water, guess what? its lighter. of course....

Cobalt Chloride Hydrate

Cobalt Chloride

Naming Compounds

Chemical Nomenclature

  Currently, the most common system that is being used to for most chemicals is the IUPAC system, otherwise known as the International Union of Pure and Applied Chemistry. This system can be used to name:

-> ions

-> binary ionic

-> polyatomic ions

-> molecular compounds

-> hydrates

-> acids & bases

Chemical Formula

  In order to write a chemical formula, you would have to be aware of the differences between ion and compound formulas. 

EXAMPLE: The picture above shows examples of ions. Ions have either a negative or a positive charge. If they have a positive charge, they are called CATIONS and if they have a negative charge, they are called ANIONS.

 EXAMPLE: The chart above has examples of compounds. They show what elements are there and how many of each exist.

Multivalent Ions

  Important ideas to keep in mind with multivalent ions are:

1. Some elements can form more than one ion

2. IUPAC uses roman numerals in parenthesis to show charge

3. Classical systems consisting of Latin names & suffixes may be used:

   -> The suffix "ic" is added at the end to represent the larger charge

   -> The suffix "ous" is added at the end to represent the smaller charge

   -> Classical names used for certain elements are:

         -Ferr = Iron

         -Cupp = Copper

         -Mercur = Mercury

         -Stann = Tin

         -Aunn = Gold

         -Plumb = Lead

EXAMPLE: The picture above is an example of how certain suffixes or names are subbed in to the formula.

Hydrates

  Hydrates are compounds that include H2O. These compounds form lattices that bong to water molecules and when heated, the H2O can be released.

  In order to name hydrates, you must:

    

    1. Write out the chemical formula.

    2. Add prefixes indicating the number of water (H2O) molecules exist.

    3. Add the hydrate (H2O) after the prefix.

EXAMPLE: COPPER (II) SULPHATE PENTAHYDRATE -> Cu (SO4) x 5H2O

                  LITHIUM PERCHLORATE TRIHYDRATE -> Li(ClO4) x 3H2O 

Molecular Compounds

  These can be created by adding prefixes to the elements to indicate how many of each element exists in the formula. As for a suffix for the latter part of the formula, you can add "ide".

EXAMPLE: DiNitrogen TetraOxide -> N2O4

                  TetraPhosphorous DecaOxide -> 3P10O

Naming Acids & Bases

 Hydrogen compounds are ACIDS:

   -> HCl = Hydrochloric Acid*

    -> CH3COOH = Acetic Acid* (Vinegar)

*Take note of hydrogen and the endings,

  

 Hydroxide (OH) compounds that include cations are BASES:

    -> NaOH = Sodium Hydroxide*

   -> Ba(OH)2 = Barium Hydroxide*

*Take note of the hydroxide ion.

Naming Ionic Compounds Video:

http://www.youtube.com/watch?v=7Lfc6jjp1WQ

Lewis Diagrams (sports update canucks over the oilers 4-3)

Electron Structure

-Drawing Electron Dot Diagrams

- The nucleus is represented by the atomic symbol.

-For individual elements determining the number of valence electrons

-Electrons are represented by dots around the symbol

-4 orbitals ( one of each side of the nucleus each holding a max of 2e-

-each orbital get 1e- before they pair up




http://www.green-planet-solar-energy.com/images/carbon-hydrogen-e-dots.gif




Lewis Diagrams for Compounds and Ions

-In a covalent compounds electrons are shared

1)Determine the number of valence e- for each atom in the molecule

2)Place atoms so that valence e- are shared to fill each orbital




http://www.walkingrandomly.com/images/chemistry/lewis-ethane.gif




Double and Triple Bonds

-Sometimes the only way covalent compound can fill all their valence levels is if they share more than on electron




http://www.fordhamprep.org/gcurran/sho/sho/images/lewdot11.jpg




Ionic Compounds

-In ionic compounds electrons transfer from one element to another

-Draw [] around the metal and non-metal

-Write the changes on the outside brackets




http://www.kentchemistry.com/images/links/binding2/covale9.gif




Lewis Diagrams for Polyatomic Ions

1) Determine the number of valence e- for each atom in the molecule

2)Subtract on electron for each + valence electron charge

3)Add one electron for each - valence electron charge



http://www.glencove.k12.ny.us/highschool/ChemRev/CovBond.jpg

VIDEO!!!!!!
http://www.youtube.com/watch?v=GFIvXVMbII0


Periodic table trends: 1. Elements close to each other on the periodic table
                                         display similar characteristics
                                     2. There are 7 important periodic trends: a. reactivity
                                                                                                   b. ion charge
                                                                                                   c. melting point
                                                                                                   d. atomic reactions
                                                                                                   e. ionization energy
                                                                                                   f. electro negativity
                                                                                                   g. density

Reactivity: 1. Metals and non-metals show different trends
                   2. The most reactive metal is Francium; the most reactive non-metal is Fluorine

Ion charge: 1. Elements ion charges depend on their group [column ]

                      

Melting point: 1. Elements in the center of the table of the highest melting point
                         2. Noble gases have the lowest melting points
                         3. Starting from the left and moving right, melting point increases [until middle of the table]

Ionization Energy: 1. Ionization energy is the energy needed to completely remove an electron from an atom
                               2. It increases going up and to the right
                               3. All noble gases have high ionization energy
                               4. Helium has the highest ionization energy
                               5. Francium has the lowest ionization energy
                               6. Opposite trend from atomic radius

Electronegativity: 1. Electronegativity refers to how much atoms want to gain electrons
                               2. Same trend as ionization energy
                             

Mass Spectrometer Demo 1

Isotopes and Atoms

Hello fellow follower of this blog, would like to thank for the follow and enjoy more of chemistry 11 (:

This is about the atom and its different forms also called isotopes.
Let us cool it down with the basics, let's talk about the atomic number.

The atomic number is basically the number of protons within an atom
You can obtain the number of neutrons by following this equation:

 Atomic mass - Atomic number = Number of Protons
       (p+n)      -          (p)           = (n)

ISOTOPES!
This is KEY to your success in your understanding of isotopes

What is an isotope in the first place!?
Well calm down, its simple.
An isotope has the same traits as an atom, with the same atomic number an all, but the secret on isotopes are that the mass between isotopes of the same element are different.

Just to clear the contradicting of "same" and "different" in the last sentence,
NOT ALL ATOMS of the SAME ELEMENT are IDENTICAL!!!

Some cool instruments are used to determine the abundance and mass of the isotopes of the elements
these are called Mass Spectrometers!

Above this, is a video of a mass spectrometer in action! Since we are in a filipino majority school, its a demo from straight from the Philippines!!! Enjoy (:  

VIDEO FOR YOU YOUNG CHEMISTS!! : http://www.youtube.com/watch?
v=rSZrZWXxxgQ

A.Bohr model diagrams: 1. Rutherford's model was inherently unstable
                                           2. Matter emits light when it's heated [ blackbody radiation ]
                                           3. Lights travels as photons
                                           4. The energy photons carry depends on their wavelength 
                                           5. Bohr based his model on the energy [ light ] emitted by different atoms
                                           6. Each atom has a specific spectra of light
                                           7. To explain this emission spectra Bohr suggested that electrons occupy
                                                shells or orbitals





B. Bohr's Theory: 1. Electrons exit in orbitals 
                               2. When they absorb energy they move to a higher orbital
                               3. As they fall from a higher orbital to a lower one they release energy as 
                                   a photon of light


SORRY FOR THE LATE POST KIDS, BUT STAY TUNED FOR WHAT'S COMING UP!!!

Quantum Mechanics

 Bohr's Theory & Model

  In order to fully understand Quantum Mechanics, we must also have a grasp on the Bohr Theory and Model as they serve as the foundation. 

 Some of the main points one most know for the Bohr Theory & Model are:
   
  1) Electrons exist in orbitals
       -> orbitals are found on energy levels/shells
       -> there are 2 electrons in the first orbital
       -> there are 8 electrons in the second orbital (called an octet when full)
       -> there are 8 electrons in the third orbital (called an octet when full)
       -> there are 18 electrons in the fourth orbital, etc.
   2) When electrons absorb energy, they move to a higher orbital
    3) As electrons fall from a higher orbital to a lower one, they release energy as a photon of light
   4) The Bohr Theory can be represented as either an Energy Level Model or the regular Bohr Model

EXAMPLE: The diagram shown above is an Energy Level Model of the atom Krypton (Kr). Instead of drawing individual dots, one can just write out the number of electrons that are to be found on each level and the number of protons and neutrons found in the nucleus.

EXAMPLE: The picture shown above are Bohr Models. Instead of colored dots, the neutrons & protons may be expressed with a number and their sign (p for protons & n for neutrons).



Quantum Theory
 The main points of the Quantum Theory are:
  
  1) An electron is like a cloud of negative energy or a wave
  2) Orbitals are areas in 3D space where electrons probably are
  3) The energy of an electron is in its vibrational modes (ie: the notes played on a guitar string)
  4) photons are produced when high energy modes change to lower energy modes 

 On each energy level, there are Orbitals:

S-Orbitals
-each orbital holds 2 electrons

 

P-Orbitals
-there are 3 sub orbitals that contain 2 electrons each (6 electrons in total)

D-Orbitals
-there are 5 sub orbitals that contain 2 electrons each (10 electrons in total)

 

F-Orbitals   
-there are 7 sub orbitals that contain 2 electrons each (14 electrons in total)

 
Diagram To Help Explain Orbitals:

  Consider the hotel above an atom. Each level in the hotel represents an energy level in the atom. Each floor on a level (distinguished by S,P,D,& F) represent the orbitals (distinguished by S,P,D, & F). On each floor there are rooms which represent the number of sub orbitals. The people standing in each room represent the number of electrons that exist in that orbital. Since the people have the ability to move around their levels, they don't have a fixed place but rather, a general area that they take up. In this sense, electrons are similar as they are thought of to be clouds of negative energy occupying a general area on their level.

*Credits:

->Bohr Diagrams:

http://lapse.nerdvana.org.au/comedy/pics/atom-bohr.gif

->S-Orbital:

http://img.sparknotes.com/figures/0/083ee1e849c82204c3d7c342d336a448/sorbital.gif

->P-Orbital:

http://img.sparknotes.com/figures/5/5578bdf1aec90e46e14325a580fdbf6a/porbital.gif

->D-Orbital:

http://img.sparknotes.com/figures/5/5578bdf1aec90e46e14325a580fdbf6a/dorbital.gif

->F-Orbital:

http://www.chemistry.ucsc.edu/~soliver/151A/Handouts/f-orbitals.gif

->Stick Figure:

http://3.bp.blogspot.com/_V5zRBX0DFfE/SaCpyJ6APBI/AAAAAAAAAGI/u0N19lXNlYs/s320/stick_figure.gif 

Bohr continued...

Bohr Model


-Atoms are electrically neutral.
-Two different models can be used to describe electron configuration.
-Electrons occupy shells which are divided into orbitals.

2e- in the first orbital
8e- in the second orbital
8e- in the third orbital
14e- in the fourth orbital


http://www.youtube.com/watch?v=FFCTiwJewz4

H2O (or dihydrogen monoxide haha) Solubility of Sodium Chloride

Hello Followers of this blog (: Today we had our first ever lab testing the solubility of water when mixed with Sodium Chloride, easily found in your normal table salt.

 So there was certain procedures that we did to measure the solubility of the water with Salt
1) Get items for the lab (graduated cylinder, scoopula, beaker, wax paper, table salt, stirring rod, scale)
2) Get the safety equipment! (even though we are dealing with salt, Mr. Doktor will Zerg rush you guys on Starcraft II if you don't....so "MAKE IT A HABIT" - Mr. Doktor)
3)Measure 10,20,40,50 mL of water with your GRADUATED CYLINDER, because using a beaker is inaccurate.
4) Then pour it in the beaker
5) Put table salt on the wax paper which is on the scale
6) Zero in the scale to make life easier.
7) Then keep on pouring salt in the water with the scoopula and keep on pouring salt until the water is soluble, which means it will show some salt crystals on the bottom of the beaker.
8) Finally record on the table, because you will forget.

FACT
Salt (NaCl) is an ionic compound used as a condiment, and also (it was a shock to me but did make sense due to taking the water out of things) as a preservative!

Density & Graphing

Density
The density of an object can be expressed through the equation:

d=m/v

Where the 'd' is the density and is found by dividing the mass of an object (m) with it's volume (v).

Density is usually expressed by the units kg/L, kg/m³, or g/cm³.

EXAMPLE: WATER AS A LIQUID HAS IT'S GREATEST DENSITY OF APPROXIMATELY 1000 KG/M³ AT 4˚C AND EVENTUALLY BECOMES LESS DENSE AS THE TEMPERATURE DROPS TO 0˚C. THEREFORE, ICE, HAVING A LOWER TEMPERATURE THAN IT'S LIQUID STATE, WOULD BE LESS DENSE CAUSING IT TO FLOAT ON LIQUID WATER.

VIDEO EXAMPLE: http://www.youtube.com/watch?v=rxb_6UANXqU

Graphing

All graphs must contain 5 aspects:

1.  Labeled axes (y-axis & x-axis)
2. Appropriate scale
3. Title (appropriate for the graph; think of the units for the y-axis & x-axis)
4. Data points
5. A line of best fit (on certain occasions, this line does not have to pass through all the points)

There are 3 things you can do with a graph:

1. Slope (rise/run; y2-y2/x2-x1)
2. Area
3.  Read the Graph

EXAMPLE: THE GRAPH SHOWN ABOVE SHOWS THE RELATION BETWEEN THE NUMBER OF WORDS ONE CAN TYPE  PER MINUTE BASED ON THE WEEKS OF PRACTICE ONE HAS.

*Some of the information and pictures found for this blog was found from the following links; all credits go to these sites:

http://marinebio.org/upload/77/Iceberg.jpg

http://wiki.answers.com/Q/Why_density_if_ice_compared_to_water_in_liquid_state

http://www.aims.co.th/Pretest_GED/Maths/Maths-_5-6.gif

 

Dimensional Analysis

- Just like converting between currencies in chemistry it is usually necessary to convert between units
- This process is called Dimensional Analysis

Steps
1. find a unit quality
2. find the conversion factors
3. apply conversion factors
4. cancel units

example
http://upload.wikimedia.org/math/b/e/4/be413a0d3340a3ec49906113fb96ac61.png
                                           

SCIENTIFIC NOTATION VIDEO :)
http://www.youtube.com/watch?v=H578qUeoBC0

SIGNIFICANT DIGITS:


If a digit is not 0, it's always significant 
If the zero is a "place keeper" it's generally not significant ex: >0.0042
Any number to the right of a decimal point are significant if they come after a non-zero number 
ex: >4.60 is 3 digits significant because it starts at 4
      >2.0 is 2 digits because it starts at 2
      >0.0035 is 2 digits because it starts at 3
When adding or subtracting, round to the least precise number ex: >7. 4212
                                                                                                      -3. 5400   
                                                                                                       3. 8812= 3.88 [ both the tenths and  hundredths value have the same value so you round it to the nearest hundredths] 
                                                                                                     > 12. 300
                                                                                                      +10. 771
                                                                                                         23. 071= 23.1 [ the smallest value is in the tenths place so you round it to the nearest tenths]


When you multiply or divide, round to the number with the fewest S.D.S ex: >2. 5 x 5. 55= 13. 875=14 
                                                                                                                    >1. 33421 x 19. 531=26. 0584551= 26.058


SCIENTIFIC NOTATION:


Shows really big or small numbers make use power of 10 ex: >10^5=100000
                                                                                             >12300000= 1.23 x 10^7
                                                                                             >0. 00000342 x 10^-6
                                                                                             >0. 0000002.97 x 10^-7 


CALCULATORS: Your calculator has functions that you can use to do this easily 
                                 [for graphing calculator models of ti-83 or newer]: 
                                 PRESS: EXP
                                               EC
                                               X 10
                                               S.N.
DO NOT USE " ^ " ON YOUR CALCULATOR FOR YOUR CHOSEN EXPONENTS 


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