IGCSE Coordinated Sciences Y1 Unit 2: Chemistry C01, C03, C8.4, C4 Key Notes.
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Transcript of IGCSE Coordinated Sciences Y1 Unit 2: Chemistry C01, C03, C8.4, C4 Key Notes.
IGCSE Coordinated Sciences Y1
Unit 2: ChemistryC01, C03, C8.4, C4
Key Notes
Physical and Chemical Changes
• Read pages 47 in your textbook.• What is a chemical change?• How is it different from a physical
change?• Describe some indicators that tell us
a chemical change has occurred.
Physical or Chemical?Demo Physical? Chemical?
Both?Explanation
Heating Wax
Burning a Candle
Sugar and Water
CuCl2 and Al foil
Tearing Paper
Colored Water
KI and Pb(NO3)2
Vinegar & Baking Soda
Evidence of Change…
Evidence of Physical Changes• Change in phase or state
• Example: liquid → solid
• Mass or volume change• Color change that is not permanent
Evidence of Change…
Evidence of Chemical Changes• Energy is given off or taken in• Light is observed • Heat is given off• Bubbling or fizzing• Permanent color change
What is everything made of?
• Important vocabulary:– atom, – element, – molecule, – compound, – mixtures
• Write a definition & draw a picture for each term using pg. 30, 31, 46, & 54
• Then, write about the similarities and differences between each.
Sentence starters
• An element is unique because it…• Molecules are similar to compounds
because…• A molecule is different than a
compound because …• A mixture is different than either a
compound or molecule because…
What is inside an atom?
• Read & take notes on the description of an atom on Page 32 - 33.
• Watch the video clip about structure of an atom.
Atom Summary
• Fill in the table with information about the different parts of an atom:
Particle Charge Location in atom
Relative Mass
Proton
Neutron
Electron
Silent Teacher
• We are going to play a game to determine what you remember about atoms.
• As you start to recognize patterns, fill in your chart. Have your teacher check your work, then if asked, write up an answer on the group chart.
• Discover the patterns and then write the rules if you figure them out!
Quick Tour of the Periodic Table
• Atomic number• Atomic mass / nucleon number• Periods vs. Families• Metals, transition metals, non-
metals, noble gasses
Practice/ Review
Element p+ e- n0
HydrogenSulfurIodineSodium
Isotopes
• How can an element like Chlorine have an atomic mass of 35.5?
• Isotopes are atoms of the same element (same proton number) with different numbers of neutrons.
• Most elements have isotopes!
Chlorine
• Chlorine – 35 has an atomic mass of 35. How many protons does it have? How many neutrons?
• Chlorine – 37 has an atomic mass of __.p+ = _____ no= ______
• Of all the chlorine atoms in the world, 75% are chlorine-35 and 25% are chlorine-37, giving an average atomic mass of 35.5.
Atomic Orbitals
• Electrons travel around the nucleus in orbitals. • We will study the first 3 orbitals:
– The first orbital can hold up to 2 electrons– The second orbital can hold up to 8 electrons– The third orbital can hold up to 8 electrons
• Orbitals always fill from the inside out.• Example: Lithium
Example Atom
• Example: Lithium
Try These
Try these:• Hydrogen
• Aluminum
Practice Time!• Obtain a “building atoms” sheet on
Haiku. • Use your baggie of particles to build
each atom from the sheet, recording your results in your journal.– Be sure to put the correct number of
electrons in each orbital and show the number of protons and neutrons in the nucleus!
– Put your name on your baggie and save your particles for later. You’ll get to eat them later
Electronic Configurations
• Scientists use a shorthand to denote how many electrons are in each orbital or energy level of an atom.
• See Page 36 for an example!• Go back to your atom drawings and
write the electronic configurations for each atom you built.
A FULL outer shell
(valence electrons)
What does every atom want?
Gaining and Losing Electrons
ION: an atom that has gained or lost electrons.
• Cation: An atom that has lost one or more electrons. Positively charged.
• Anion: An atom that has gained one or more electron. Negatively charged.
Becoming an ion…
How many electrons must be gained or lost by each atom? • Lithium • Argon • Chlorine • Potassium • Phosphorus • Magnesium
Trends on the Periodic Table
• Group 1 loses one electron; they all have +1 charge.
• Group 6 gains two electrons; they all have a –2 charge.– Group I +1– Group II +2– Group III +3– Group V -3– Group VI -2– Group VII -1– Group VIII 0
Forming an Ionic Compound
• How do metals and nonmetals come together to form IONIC bonds?– Explain in your notes using an example
from your reading on page 50 – 51.– Show using your baggie of candy
“particles” the formation of:• Lithium + Fluorine
(how many of each atom do you need?)• Lithium + Oxygen
(how many of each atom do you need?)
Arrangement of Particles in Ionic Compounds
• When sodium and chlorine bond, they form a lattice structure made up of repeating units of positive and negative charges.
• Building a lattice structure
Lattice Structure
Forming Compounds
• Determine the formula for the compound made when the following atoms combine…–Magnesium + Bromine
– Sodium + Oxygen
– Aluminum + Fluorine
Simple Ionic Compounds
• How to write and name ionic compounds! – When writing the formula, first write the
symbol and charge of each ion.• Switch the charges and write them as subscripts.• Simplify!
– When naming a compound, write the name of the cation first then the anion with an –ide ending.
– Use roman numerals for ions with more than one charge [i.e. Fe+3 would be Iron (III), Fe+2 is Iron (II)]
Practice Chloride, Cl-
1
Bromide, Br-1
Oxide, O-2
Sodium, Na+1
Magnesium, Mg+2
Aluminum, Al+3
Chloride, Cl-1
Bromide, Br-1
Oxide, O-2
Sodium, Na+1
NaCl NaBr Na2O
Magnesium, Mg+2
MgCl2 MgBr2 MgO
Aluminum, Al+3
AlCl3 AlBr3 Al2O3
Ionic Compounds with Polyatomic Ions
• A Polyatomic Ion is an ion made up of more than one type of atom.
• Most have a negative charge, with the exception of ammonium.
• Ionic Compounds with polyatomic ions are written and named in the same manner as binary compounds.
Ionic Compounds with Polyatomics
The only exceptions are:• Each polyatomic ion is treated as one element
• Parenthesis are used around the entire ion when expressing the quantity necessary to balance out the charge– Ex. Cu+2 + OH-1 Cu(OH)2 and is named Copper (II)
Hydroxide
• Polyatomic ions are named according to their own naming convention – Ex. Li3PO4 is called Lithium Phosphate
Polyatomic Practice
• Ca+2 + PO4-3
• Mg + ClO4
• Cu+1 + SO4
• Aluminum Hydroxide
• Iron (II) + Permanganate
Practice Hydroxide,
OH-1
Nitrate, NO3
-1
Carbonate, CO3
-2
Sulfate, SO4
-2
Sodium, Na+1
Magnesium, Mg+2
Aluminum, Al+3
Ammonium, NH4
+1
Hydroxide, OH-1
Nitrate, NO3
-1
Carbonate, CO3
-2
Sulfate, SO4
-2
Sodium, Na+1
NaOH NaNO3 Na2CO3 Na2SO4
Magnesium, Mg+2
Mg(OH)2 Mg(NO3)2 MgCO3 MgSO4
Aluminum, Al+3
Al(OH)3 Al(NO3)3 Al2(CO3)3 Al2(SO4)3
Ammonium, NH4
+1
NH4OH NH4NO3 (NH4)2CO3 (NH4)2SO4
Practice• 1. Do the “Polyatomic Naming”
sheet found on Haiku.• 2. IF more time remains, do another
practice sheet from “Ionic Bonding” block on Haiku
Covlaent Bonding
• Covalent bonds occur between two or more non-metals.
• Valence electrons are shared to complete atoms outer shells.
Review: Ionic bonds occur between metals and non-metals.
Naming Covalent Compounds
• CO2
• CO
• H2O
Forming Covalent Bonds
• Dot and Cross Structures & Line structures
• Hydrogen + Hydrogen • Hydrogen + Oxygen
• Bromine + Bromine
• Oxygen + Oxygen
• Carbon + Oxygen
Building Covalent Compounds
• Build each covalent compound on the half sheet.
• Draw a color coded 3-D picture of the actual compound in your notebook.
• Draw a dot and cross structure for each compound beneath your drawing.
Modeling Lab Instructions
• There should be no empty holes in your atoms
• There should be no empty bonds in your compounds
• You cannot build rings of 3 or 4 atoms
Materials Key
• Carbon = Black• Hydrogen = White• Oxygen = Red• Halogens= Green• Nitrogen = Blue (ignore one
hole)• Bonds = Gray Tubes
• Describe how a molecule of ammonia (NH3) is made. Include a description of how each covalent bond is formed.
Giant Structures
• To finish out our study of Covalent Compounds, read about:– Giant Covalent Structures (pg. 60 - 61)– Simple Molecular Structures (pg. 56 -
57)
• How does the structure of a compound or molecule affect its properties?
Ionic vs Covalent Compounds
• What are the differences in the properties of ionic vs. covalent compounds?
• Read pg. 58 - 59
IN:
Work on these problems as I check off your homework:
What is wrong with these formulas?• Zn+2 + O-2 Zn2O2
• NH4+ + NO3
- NH3NO4
• Fe+3 + CO3-2 Fe2CO33
Chemical Equations
• Reactants products
Na2SO4 (aq) + CaCl2 (aq) CaSO4 (s) + 2NaCl (aq)
• The state of each reactant and product can be shown with a small symbol in parenthesis at the end of each formula (see above).– s for solid, l for liquid, g for gas, and aq if
the compound is an aqueous solution
Writing Chemical Equations
• Lead (II) nitrate solution reacts with potassium iodide solution to form lead (II) iodide solid and potassium nitrate solution.
• Copper metal reacts with oxygen gas (O2) to form copper (II) oxide.
Writing Chemical Equations
• Iron metal reacts with water to form iron (III) oxide solid and hydrogen gas (H2).
• magnesium hydroxide solution + carbon dioxide
water + solid magnesium carbonate
Balancing Chemical Equations
• When a chemical reaction happens bonds are broken, elements get rearranged, and new compounds are formed.
• The Law of Conservation of Matter tells us matter (or mass) cannot be created or destroyed!– The number of atoms of each type is the
same in both the reactants and products!
Demo
• Baking Soda & Vinegar
Balancing Equations• Step 1: Take an atom inventory • *List the type and number of each atom
on both sides of the chemical equation • H2CO3
• Ba(OH)2
• C3H8
• NaC2H3O2
• Al(NO2)3
• Step 2: Law of Conservation of Mass
*We must have the same number of atoms of each type on both sides*Use Coefficients to balance
~Example: 2NH3
H2 + O2 H2O
• FeS + HCl FeCl2 + H2S
• Fe2O3 + H2 Fe + H2O
• P + O2 P2O5
Homework
• Work through the practice problems on the Balancing Equations practice sheet. (Download from Haiku).– Show your atom inventory for every
problem!
• Do the “Writing and Balancing Equations WS” (Find on Haiku).