LAB: Iron and and Copper Chloride

Problem: What is the ratio of moles of Copper formed to moles of Iron reacted in the chemical reaction described below?

To find the answer to this question our group placed an Iron nail in a solution of Cupric Chloride after measuring the filter paper and mass of the nail. We observed an immediate change in the color of the nail; it turned a rusty red. We learned that the iron was dissolving. These dissolved iron particles will combine to form Ferric Chloride. After, we removed the nail form the solution and dried it then we transfered the solution in to a separate beaker using filter paper. We measured the mass of the nail. It took a long time for the solution to filter. We determined the mass of Iron consumed  by comparing the mass of the nail before and after the reaction. After the solution had filtered we transferred the Ferric Chloride and the filter paper to dry in the drying oven. We have yet to measure its mass then we can determine the mass mass of the Ferric Chloride formed.

Group: Jennifer, Jomar, Paulette

Density and Moles

Density
-Density is a measure of mass per volume d = m
                                                                      V
-measured in g/L or g/mL

Example
-Water has a density of 1.0g/mL. Determine the mass of 11.5mL of water
-How many moles are in 11.5mL of water?

1.0g/mL x 11.5mL = 11.5g
11.5g x 1 mol = 0.64 mol
             18 g

Density of Gases

-The density of gases varies with temperature

-At STP we can find density by:  MM              molar mass               

                                               22.4L/mol        molar volume

Example
-Calculate the density of 02 STP

32.0g/mol = 1.43g/L
22.4L/mol

-An unknown diatomic gas has a density of 1.696g/mol STP
 -Find its molar mass
 -What is the chemical formula

1.696g/L x 22.4L/ 1 mol = 37.99g/mol = 38g/mol
                                                                  2
                                                            = 19g/mol
Chemical formula : F2

Mass to Volume Conversion

- At a specific pressure and temperature one mole of any gas occupies the same volume.

- At 0 degrees Celsius and 101.3 kilo Pascals 1 mol = 22.4 L

- This temperature and pressure is called STP

- 22.4 L/ mol is the molar volume at STP

Example:

How many litres will 2.5 mol of hydrogen gas occupy at STP

1) 2.5 mol hydrogen gas = 22.4 L/ 1 mol = 556 L

litres to mols

2) 11.6 L = 1 mol/ 22.4 L = 0.518 mol

Example:

At STP a sample of oxygen gas contains 11.5 mol.
How many litres of oxygen gas are there?

11.5 mol = 22.4 L/ 1 mol = 258 L

150ml x 1 L/ 1000 ml = 0.15 L

0.15 L x 1 mol/ 22.4 L = 0.00670 mol

Extra Notes:
-In conversions mols will almost always equal 1
-Remember to convert values to the appropriate units when asked for a different unit
-Also remember to use significant figures because these are very important in conversions

Molar Mass Mass of Atoms

 Molar Mass
-The mass ( in grams ) of 1 mole of a substance is called the molar mass
- It can be determined from the atomic mass on the periodic table
- Measured in g/mol

Molar Mass of Compounds

- To determine the molar mass of a compound add the mass of all atoms together

Example

Element                  Molar Mass              *Significant Digits

H2O                   2 + 16 = 18.0g/mol  
NO2                  14 + 32 = 46.0g/mol
NaCl                  23 + 35.5 = 58.5g/mol  
FeO                   55.8 + 16 = 71.8g/mol
NaNO3             23 + 14 + 48 = 85.0g/mol

 Converting between moles and mass
- To convert between moles and mass we use molar mass as the conversion factor
- Be sure to cancel the appropriate units

Examples

How may grams is there in 1.5 mol of O2?


1.5mol O2 x 32.0g   = 48g
                  1 mol O2


Example

A sample of HCl contains .54 mol. How many grams of HCl is this?

.54mol HCl x 36.5g     = 20g HCl
                    1 mol HCl


Example

A compound is made of phosphorus and chlorine. It is found to contain 0.200 mol and has a mass of 27.5g
- Determine the molar mass of the compound
- Suggest a possible formula

0.200mol x 27.5g  =  137.5g/mol            Formula = PCl3
                        1 mol

Naming Compounds

Chemical Nomenclature

-Today, the most common system is IUPAC for most elements like,

1. Ions
2. Binary Ionic
3. Polyatomic Ions
4. Molecular Compounds
5. Hydrates
6. Acids/Bases

Chemical Formulas

-Beware of the differences between Ion and Compound Formulas

Eg.


Zn^2+ (The 2+ means an Ion Charge)
BaCl2   (The 2 means the number of Ions)

Multivalent Ions

-Some elements can form more than one ion.
  -Eg. Iron > Fe^3+ or Fe^2+
  -Eg. Copper > Cu^2+ or Cu^1+
-The top number on the P.T. (Periodic Table) is more common
-IUPAC was uses roman numerals in parenthesis to show the charge
-Classical (i.e. Old) systems uses latin names of elements and the suffixes like '-ic' (larger charge) and '-ous' (smaller charge)
  -Eg. Ferric Oxide
            /\
      Refers to Iron (Fe)
      '-ic' refers to larger charge
      So iron's charge would be +3 not +2

Other Classical Names
-Ferr - Iron
-Cupp - Copper
-Mercur - Mercury
-Stann - Tin
-Aunn - Gold
-Plumb - Lead

Eg.  FeCl2 - Ferrous Chloride
       SnO2 - Stannic Oxide
       Pb(NO3)2 - Plumbous Nitrate

Hydrates

-Some compounds can form lattice that bond to water molecules

   -Copper Sulfate
   -Sodium Sulfate                                   Without water, the compounds is often preceeded by 'anhydrous'


-These crystals contain water inside them which can be released by heating
-To name hydrates

1. Write the name of the chemical formula
2. Add a prefix indicating the number of water molecules (mono, di, tri, tetra, penta etc..)
3. Add hydrate after the prefix

Eg. Li(ClO4) 3H2O - Lithium Perchlorate Trihydrate

Molecular Compounds

-Write names of the following compounds

N2O4 - Dinitrate Tetraoxide

Naming Acids/Bases

-Hydrogen compounds are acids
   HCl > Hydrochloric acid

Naming Bases

-Caution and OH
   -NaOH - Sodium Hydroxide

Trends on the Periodic Table

-Elements close to each other on the periodic table display similar characteristics
-There are 7 important periodic trends
1. Reactivity
2. Ion charge
3. Melting point
4. Atomic Radius
5. Ionization energy
6. Electronegativity
7. Density*

Reactivity

-Metals and non-metals show different trends

-Te most reactive metal is Francium; the most reactive non-metal is Fluorine

Ion charge

-Elements ion charges depend on their group (column)

Heres a picture of the Ionic charges:http://www.chemprofessor.com/ptable4.gif

Melting point

-Elements in the center of the table of the highest melting point

-Noble gases have the lowest melting points

-Starting from the left and moving right, melting point increases (until the middle of the table)

Atomic Radius

-Radius decrease to the up and the right

-Helium has the smallest atomic radius

-Francium has the largest atomic radius

Ionization Energy

-Ionization energy is the energy needed to completely remove an election from an atom

-It increases going up and to the right

-All noble gases have high ionization energy

-Helium has the highest ionization energy

-Francium has the lowest ionization energy

-Opposite trend from atomic radius

Electronegativity

-Electronegativity refers to how much atoms want to gain electrons

-Same trend as ionization energy

Electronic Structure

Drawing Electron Dot Diagrams

-The nucleus is represented by the atomic symbol. 

- For individual elements determine 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 maximum of 2e. 

Lewis Diagrams for Compounds & Ions

- In compounds electrons are shared

1. Determine the # of valence e- for each atom.

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

Double and Triple Bonds

- Sometimes the only way covalent compounds can fill all their valence levels is if they share more than one electron.

Ionic Compounds

- In ionic compounds electrons transfer from one element to another.

- Cation (metal - positive charge)

- Anion (non-metals - negative charge) 

Lewis Diagrams for Polyatomic Ions

1. Determine the # of valence e- for each atom in the molecule.

2. Subtract one electron for each positive charge.

3. Add one electron for each negative charge. 

Links:

The link giving step by step instructions on how to draw an electron dot diagram (shown in class)

1. http://www.youtube.com/watch?v=y6QZRBIO0-o

more info on Lewis structures of atoms, ions, and compounds.

2. http://www.ausetute.com.au/lewisstr.html

Jomar Delos Santos

Isotopes and Atoms

Atomic Number
-Atomic number=number of protons
atomic mass - atomic number = number of neutrons

Isotopes
-Same atomic number but different mass
For example there are 3 types of hydrogen atoms
1H                  2H                  3H
-Not all atoms of the same element are identical

Mass Spectrometers
-Are used to determine the abundance and mass of the isotopes of elements
-A device known as a mass spectrometer can be used to determine the relative abundance and the mass of the isotopes in an element
-Isotopes are elements that have the same atomic number(same element) but different atomic masses

Helpful links
Isotopes and atoms
http://www.chem4kids.com/files/atom_isotopes.html
http://www.daviddarling.info/encyclopedia/I/isotope.html
Mass spectrometer
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/maspec.html

Quantum Mechanics

Bohr's Theory


The electron is a particle that must be in orbital in the atom.

Quantum Theory

- The electron is like a cloud of negative energy or a wave.
- Orbitals are areas in 3D space where the electrons most probably are.
- The energy of the electron is in its vibration modes like notes on a guitar string.
- Photons are produced when high energy modes can change to lower energy modes.

S Orbitals

- Each orbital holds 2 electrons.

P Orbitals

- There are 3 suborbital
- Each contains 2 electrons
- Total of 6 electrons.

D Orbitals

- There are 5 suborbitals
- Each contains 2 electrons
- Total of 10 electrons

F Orbitals

- There are 7 suborbital
- Each contains 2 electrons
- Total of 14 electrons

To figure out what and how many electrons there are in one element while using this method we would have to look at this chart : http://www.google.ca/imgres?imgurl=http://www.mpcfaculty.net/mark_bishop/periodic_table_blocks_alone.jpg&imgrefurl=http://www.mpcfaculty.net/mark_bishop/complete_electron_configuration_help.htm&usg=__bLyOjtz-Gs86FIFcYq257xkeOzw=&h=348&w=607&sz=60&hl=en&start=0&sig2=jrC7eVhaOYmzHVETriUkqA&zoom=1&tbnid=5igjc12lXF7FoM:&tbnh=116&tbnw=203&ei=62HGTN-eJIn4swPTvaWODQ&prev=/images%3Fq%3Dperiodic%2Btable%2Borbitals%26um%3D1%26hl%3Den%26biw%3D842%26bih%3D935%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=219&oei=62HGTN-eJIn4swPTvaWODQ&esq=1&page=1&ndsp=15&ved=1t:429,r:3,s:0&tx=111&ty=30

To see how many electrons and what type of electrons there are in a single element you would have to look at the chart.

For example, to find Magnesium(12) you would have to start off at Hydrogen which will start off as 1s^2.

To get 1s^2 you would have to look at the chart and see how many 1s are there, there are 2 so you would have to square it, and you keep on doing that until you stop until Magnesium.

So then your final answer would be, 1s^2 2s^2 2p^6 3s^2

It stops at 3s^2 because that's where Magnesium is. But if it would stop at Sodium which is one before Magnesium. Your answer would be almost the same, but instead it would look like this, : 1s^2 2s^2 2p^6 3s

-A Meldrick Mendoza productions : )

Bohr Models (I forgot to submit this last class)

-Atoms are electrically neutral

-Two Different models can be used to describe electron configuration.

1. Bohr Model
2. Energy Level Model

-Electrons occupy shells which are divided into orbitals

What information you need to make a model:

# of protons (atomic number)
# atomic mass
# of neutrons > this is found by subtracting the mass number by the atomic number.

Number of electrons each shell can contain (up to 4)
1. 2e
2. 8e
3. 8e
4. 18e

-Electrons are paired in Bohr Diagrams except on the first shell; they are on opposite sides.

Examples:

Bohr Diagram of sodium
http://www.green-planet-solar-energy.com/images/sodium-bohr.gif

Jomar Delos Santos

Bohr's Model

- Bohr (1920s)

-Rutherford's model was inherently unstable
            -Protons and electrons should attract each other
-Matter emits light when it is heated (blackbody radiation)
-Light travels as photons
-The energy photons carry depends on their wavelength
-Bohr based his model on the energy (light) emitted by different atoms
-Each atom has a specific spectra of light
            -To explain this emission spectra Bohr suggested that electrons occupy shells or orbitans

Bohr's Theory

-Electron's exist in orbitals

-When they absorb energy they move to a higher orbital

-As they fall from a higher orbital to a lower one they release energy as a photon of light

Here's a picture of a couple of Bohr models: http://lapse.nerdvana.org.au/comedy/pics/atom-bohr.gif

Four Element Theory

                  wetness

               water wind

 coldness                    hotness

                earth   fire

                  dryness

-the four elements theory lasted for about 2000 years

-it's not a scientific theory because it could not be tested

-in 300BC Democritus said atoms were invisible particles

-this was the first mention of atoms in history

-not a testable theory only a conceptual model

-no mention of any atomic nucleus

-cannot be used to explain chemical reactions

Lavoisier (late 1700's)

-law of conservation of mass

-law of definite proportions (water is always 11% H and 89% O)

Proust (1799)

-if a compound is broken down into its constituents the products exist in the same ratio as in the compound

-experimentally proved Lavoisier's laws

Dalton (early 1800's)

-atoms are solid, indestructible spheres (billard balls)

-provides for different elements(these would be different spheres)

-based on the law of conservation of mass

-having a molecule(atoms combine in whole number ratios) explains the law of constant composition

J.J Thomson (1850's)

-raisin bun model

-solid, positive spheres with negative particles embedded in them

-first atomic theory to have positive (protons) and negative (electrons) charges

-demonstrated the existence of electrons using a cathode ray tube

Rutherford (1905)

-showed that atoms have a positive, dense center, with electrons outside it

-resulted in a planetary model

-explains why electrons spin around nucleus

-suggests atoms are mostly empty space

Helpful Links

four element theory-https://reich-chemistry.wikispaces.com/Fall.2008.MMA.McCarthy.Timeline

Lavoisier-http://cti.itc.virginia.edu/~meg3c/classes/tcc313/200Rprojs/lavoisier2/home.html

Proust-http://www.ausetute.com.au/atomichist.html

Dalton-http://www.chemheritage.org/discover/chemistry-in-history/themes/the-path-to-the-periodic-table/dalton.aspx

J.J Thomson-http://www.aip.org/history/electron/jjhome.htm

Rutherford-http://www.rsc.org/chemsoc/timeline//pages/1911.html

Other-http://www.youtube.com/watch?v=5pZj0u_XMbc

-Kerr Pili

Sodium Chloride Lab

On October 5th, 2010, our class did an experiment about water and salt (Sodium Chloride).

Our experiment was, how much salt can dissolve in 200mL of water.

We had four trials, and in each trial we have different amount of water.

The first trial was with 10mL of water and the mass of salt we got was 0.38g (Yeah, we got really results.)

Second test with 20mL of water, the mass of the salt was 1.03g.

Third test with 40mL of water, the mass of salt was 1.53g.

Our last test with 50mL of water, we got 2.11g of salt.

-Meldrick Mendoza Productions : )

Density & Graphing

Density

- The density of an object is it's mass divided by it's volume.

formula:

d=m/v

And is usually expressed in kg/L, kg/m cubed, or g/m cubed

Example

- Determine the density of a statue that has a mass of 135kg and a  volume of 65L

d= m/v

d= 135 kg/ 65L = 2.1 kg/L

Graphing


- All graphs must contain 5 important things:

1. Labelled axes
2. Appropriate scale
3. Title
4. Data points
5. Line of best fit

- There are 3 important things you can do with a graph:

1. Read the graph
2. Find the slope
3. Calculate the area

Archimedes Density and Dispalcement theory

 density measurement  device

 

Legend says that Archimedes discovered the principle of displacement while stepping into a full bath. He realized that the water that ran over equaled in volume the submerged part of his body. Through further experiments, he deduced the above mentioned Archimedes' principle. 

description source : http://www.juliantrubin.com/bigten/archimedesprinciple.html

Jomar Delos Santos

Block E

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 equality

2. Find the conversion factors

3. Apply conversion factor

4. Cancel units

Example

- How many miles are equal to 120 km?

1 mile = 1.6 km                               Unit equality

1 = 1 mile                                       Conversion factor

      1.6 km

(120 km)(1 mile)                            Use the conversion factor

               1.6 km 

= 75                                               Cancel units

Heres a short and simple way to explain if your on the right track: da_flow_chart.gif

Scientific Notation and S.D

Significant Digits

-non zero digits are always significant
-if the zero is a place keeper it is generally not significant
-any numbers to the right of a decimal point are significant if they come after a non zero number
-When adding or subtracting round to the least precise number
     -Example 7.4212-3.54=3.8812 --->3.88
                     12.3+10.771=23.071--->23.1
-When you multiply or divide round to the number with the fewest S.D's
     -Example 2.5x5.55=13.875--->14
-Constants on the data sheet have infinite S.D's

Scientific Notation
-used if we need to write a number like 1000 with only 2 S.D's
-used if we want to write the number thirty three billion four hundred million without taking up an entire line
-shows really big or really small numbers easily

Here is a video on Scientific notation and S.D http://www.youtube.com/watch?v=IIQPHC5gZT8

-Kerr Pili

SI System and Percent Error Summary

SI Prefixes


The SI system uses many prefixes to show very large or very very small amounts of numbers.

Eg.

Tera (T) 10^12
Giga (G) 10^9
Mega (M) 10^6
Kilo (K) 10^3
Hecto (h) 10^2
Deca (da) 10^1
Fundamental Units
Deci (d) 10^-1
Centi (c) 10^-2
Milli (m) 10^-3
Micro (u) 10^-6
Nano (n) 10^-9
Pico (p) 10^-12
Femto (fm) 10^-15

Here's a link where you can learn more about the SI System

http://www.youtube.com/watch?v=ruBZ_yj1mEY

Experimental Accuracy


The maximum accuracy of any measurement  is one half of the smallest division of the measuring instrument.

Eg. Ruler with the lowest of measurements is millimeters. It has a maximum accuracy of +/- 0.5mm

Eg2. The odometer in a car has a maximum accuracy of +/- 50m

Eg3. Graduated cylinder has units of 1.0mL so the accuracy of  a cylinder is around +/-0.5mL

Expressing Error

Finding error is part of science!

There are usually 3 reasons why there is error.

1. Physical errors in the measuring device
2. 'Sloppy' measuring
3. Changing ambient conditions

Calculated Errors


There are two possibilities of calculated errors.

1. Absolute Error
2. Percentage Error

Absolute Error = Measured - Accepted

Positive numbers means you're over the accepted value and negative numbers means you're under the accepted value.

Percent Error


Percent error is the most common out of all the errors.

Percent error can be calculated by

% Error = [Measured - Accepted/Accepted] x 100
(The symbols '[ ]' represent the it's absolute value)

Eg.

[17.5N - 15N/17.5N] x100
= 14%

For more information about Percent Error can be found on this link below :

http://www.youtube.com/watch?v=jm7qUpPyY7w

-Meldrick Mendoza productions. : )

Chemistry 11 Blog!

Welcome to our blog everyone!