Tuesday, October 27, 2009

Mole Ratio Lab!

Today we did a mole ratio lab, which included the following:

+ ---->+


2Fe + 3CuCl2 ---> 3Cu + 2FeCl3

We:
-wanted to discover the amount of moles of copper made in the reaction of iron and copper ii chloride
- wanted to discover the amount of moles of iron was used in the reaction
- wanted to figure out the ratio of moles of iron to moles of copper
-wanted to figure out the amount of atoms and formula units.

Please refer to lab report for materials and procedures, in-class.

To sum it up:
We mixed the CuCl2 with water, then let the iron nails sit in it for a number of minutes. Before we put in the nails, the solution was bright blue, but with the addition of iron it produced a brownish color, and copper formed on the nails. We scraped the copper off the nails, decanted the copper, and found that 2.25g of copper was produced after 8.19g of CuCl2 was added.

Here is a youtube video very similar to our experiment, except the iron was kept in the solution for a longer time.


(apologies for the spelling errors, this is the most decent video we could find, and it shows all the steps!)

Saturday, October 24, 2009

Gases and Moles

- the volume occupied by a certain gas depends on the temperature and pressure

..these are 2 very important things to remember..
  1. STANDARD TEMP. = (t=0 degrees Celsius) and PRESSURE = (P=101.3kPa)
  2. the volume of any gas at STP is 22.4L/1 mol or 1 mol/22.4L
examples:

1) find the volume occupied by 0.060mol of CO2 at STP
0.060mol x 22.4L/1mol = 1.34L = 1.3L

2) find the mass of a 100.0mL sample of NO2 at STP
100.0mL x 1L/1000mL x 1mol/22.4L x 46.0g/1mol = 0.41g


This is a quick review about moles(refer to the bottom of the link's page to what we learned about gases!)

Tuesday, October 20, 2009

the MOLE con't

watched the most loveable austin powers today to set the mood :P

for all those people who werent here last class and are too lazy to scroll down one entry, ill go over the mole again.

1mole=6.02 x 10^23

if we had a mole of your everyday pea we would have enough to cover earth 200+ times! thats how freakin small an atom is.

atomic mass is equal to the mass of one mole of the element it is the mass of. that was confusing sentence so let me make it easier with an example

the atomic mass of carbon is 12.01 right? so one mole of carbon is 12.01g of carbon! comprende?

molar mass (or molecular mass) is the mass in grams of 1 mole of the molecules of an element or compound.

so lets say you gots your typical water molecule. thats H2O is it escaped your memory. that means we have 2 hydrogen atoms and 1 oxygen atom. so the the molecular mass of one hydrogen atom is 1 gram so 2 must be 2 grams. now all we do is add that to the mass of the oxygen atom (which is 16 grams) and voila! 18g/mol is the molar mass of an H2O molecule.

need me to spell it out how we did that? here i will

2Hydrogen= 2(1.0) + 1Oxygen= 16

thus... 2.0+16=18.0

ahhhhhh make more sense now?

we did some other examples in class and mr doktor started to get tricky with us by making us convert kg and mg and such, but thats all stuff we've learned before so yeah!

haha "that was easy"




here is today's daily double to see if YOU know what you've learned!!!"

Friday, October 16, 2009

What Is The Mole?!


Rufus the naked mole rat??? NO! We're learning about the OTHER mole....
THE MOLE
The mole is a quantity of a substance that has a mass in grams numberically equal to its formula mass (6.02 x 10 to the 23rd power). It is just another way to represent a number.
Example: triplets = 3, a dozen = 12, a mole = 6.02 x 10 to the 23rd power.
The number 6.02 x 10 to the 23rd power is also known as AVOGADRO'S NUMBER.

How big is Avogadro's Number?
Imagine a small green pea, it covers one cubic centimeter. 1 mole would cover the entire earth plus the pathway to jupiter!!

How Gases Combine
John Dalton look at the masses of gas
11.1 g of H(2) reacts with 88.9 g of O(2)
46.7 g of N(2) reacts with 53.3 g of O(2)
42.9 g of C reacts with 57.1 g of O(2)
In this observation there are no patterns
Joseph Gay-Lussac
1L of H(2) reacts with 1L of Cl(2) to create HCL
1L of N(2) reacts with 3L of H(2) to create NH(3)
2L of CO reacts with 1L of O(2) to create 2L of CO(2)
In this observation there is a pattern. Reactions occur in simple ratios

Avogadro's Hypothesis
Equal volumes of any gas at the same temperature and pressure contain equal numbers of molecules.

As for the fun parts of class we blew up more balloons. One filled with Hydrogen and the other with Hydrogen and oxygen. The balloon filled with both hydrogen and oxygen should have blown up louder than the balloon with hydrogen but a hole was burnt into the balloon. Mr. doktor brought his potato gun and the result was a big bang and the wet tissue being blasted at the wall on the floor.
This is what the potato gun looked like.

Wednesday, October 7, 2009

Acids and Bases

Today we started off with some fascinating experiments! One of note was when we combined sugar and sulfuric acid which produced carbon and water. here is a video summarizing what happened:




the equation is:
C12H22O11(s) → 12 C(s) + 11 H2O(aq)

We also learned about acids and bases.

Acids
- solid liquid or gas at SATP - Standard Ambient Temperature and Pressure
- form conducting aqueous solutions
- turn blue litmus red
- dissolve in water to produce H+
- Tastes sour
- PH of less than 7

Bases
- turn red litmus blue
- slippery
- nonconductive
-dissolve in water to produce OH-
- PH of more than 7

here are some common acids and bases you can find around your home:


Naming Acids
- Acids are aquaeous (dissolved in water)
- Hydrogen compounds are acids
- HCl(aq) ---> hydrochloric acid
- H2SO4(aq) --> Sulfuric Acid

- Hydrogen appears first in the formula unless it is part of a polyatomic group.
-CH3COOH ----> acetic acid
(aka C2H4O4 but usually appears in the first form as that is how it is structured: )




HI(aq) Hydro Iodic Acid
notes: the "ic" replaces the "ide" ending in iodide, hydrogen is added and the 'gen' is dropped

- Classical rules use the suffix -ic and/or the prefix hydro-
- eg. sulfuric acid, hydrochloric acid

- IUPAC system uses the aquaeous hydrogen compound
- eg. HCl(aq) ---> Aquaeous Hydrogen Chloride

Naming Bases
- For now, all bases will be aquaeous solutions of ionic hydroxides.
eg. NaOH - sodium hydroxide, BaOH2- Barium Hydroxide
- Use the cation name followed by hydroxide (see above)

INTERESTING FACT: the "ous" in nitrous acid HNO2(aq) means that this unit has "the smaller #) of oxygens in the polyatomic ion.

To practice naming acids and bases, Click here!!!

Tuesday, October 6, 2009

Hydrates and Molecular Compounds

Hydrates
  • some compounds can actually form lattices that bond to water molecules. some examples of these are copper sulfate and sodium sulfate.(without water the compound is often preceded by -anhydrous)
  • these crystals contain water inside them which can be released by heating.
Naming Hydrates
  1. write the name if the chemical formula
  2. add a prefix indicating the number of water molecules
  3. add hydrate after the prefix
ex/ Cu(SO4) . 5H20(s) = copper(II) sulfate-pentahydrate
nickel(II) sulfate - hexahydrate = Ni(SO4) . 6H2O(s)
..(keep in mind that if an element ends in -ic it is referring to the larger charge and when the element ends in -ous it is referring to the smaller charge)

here is a simple website you could use to test and practice your understanding!

Molecular Compounds
  • composed of 2 or more non-metals
  • low melting and boiling points
  • share electrons rather than exchange
  • usually end in -gen(hydrogen, oxygen, nitrogen)
  • 7 molecules are diatomic(H2, N2, 02, F2, Cl2, Br2, I2)
  • 2 molecules are polyatomic(P4, S8)
Examples/ N204 - dinitrogen tetraoxide
SC2 - carbon disulfate
sulfur dibromide - SBr2
dihydrogen exide(water) - H2O

Here is a list of Molecular Compounds that have their own very special names..

IUPAC Formula
water H20
hydrogen peroxide H2O2
ammonia NH3
glucose C6H12O6
sucrose C12H22O11
methane CH4
ethane C2H6
propane C3H8
octane C8H18
methanol CH3OH
ethanol C2H5OH

here is another website where you can read more about molecular compounds and practice your understanding!

OR if you're not into the website thing.. here's a quick video!


Enjoy! :)

Thursday, October 1, 2009

Mixtures, Atoms and the Periodic Table

Mixtures
Yesterday in class we reviewed the various ways of separating mixtures. A few of the most commonly used methods to separate homogeneous mixtures are distillation filtration and chromatography.

A) B)C)
- Figure A is showing distillation, where the substance's state is changed from a liquid to a gas and back to a liquid by boiling the liquid substance.
- Figure B is showing filtration, which can be used to separate solid and liquid parts of a mixture
- Figure C is showing the results of chromatography, where a solution can be separated by allowing it to flow along a stationary substance

Atoms
- matter is made up of atoms
- molecules are groups of atoms held together by electrical bonds
- ions are atoms or molecules that have an electric charge
- (+) cations(remember, cations are PUSSYtive)
- (-) anions
- atoms are made up of 3 sub-atomic particles
- protons have a positive charge, are inside the nucleus, each element has a different number of protons and the number of protons in an element is called its atomic number
- neutrons are neutral, they are inside the nucleus, have often the same mass as protons and adding or removing neutrons doesn't change the element
- electrons have a negative charge, are located outside of the nucleus, are 1800 times smaller than protons and chemical reactions occur between electrons in different atoms/compounds

Periodic Table
.. just a few quick facts/reminders about the PT
- Families(or groups) form vertical columns, all elements of a family have similar traits/characteristics
- Periods are horizontal rows. Elements gradually change from metals to non-metals as you move from left to right.
- most elements use Latin names as well(some exceptions are copper-cuprum, gold-aurum, iron-ferrum, lead-plumbum and silver-argentum)

Naming Nomenclatur
Naming chemical compounds has been a very difficult task and different systems have been used through the centuries. Today the most common system is IUPAC for most chemicals(ions, binary ions, polyatomic ions, molecular compounds and acids)

When you are naming ions remember there are metals, non-metals and polyatomic ions. For metals, use the name of the element and add the ion(AL+3 = aluminum ion). For non-metals, remove the original ending and add -ide(F=fluorine to fluoride). And remember that polyatomic ions have special names.

When you are creating binary ionic compounds, know that they contain a metal and a non-metal. Also know that metallic and non-metallic ions bond together, that the electron is transferred from the metal to the non-metal and the net charge must always be zero.

This is a handout you can use to practice naming and writing chemical formulas