class notes: elements and
TRANSCRIPT
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Elements and Compounds Notes 2016.notebook January 15, 2019
Class Notes: Elements
and Compounds
They are both "Pure Substances"
Periodic table asap 2 min.https://www.youtube.com/watch?v=VgVQKCcfwnU&t=2s
WHAT IS A
"PURE SUBSTANCE?"
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Elements and Compounds Notes 2016.notebook January 15, 2019
Pure substance: When all the particles in a substance are alike
What are four examples?
What is the simplest pure substance?
If you melt IRON, does it become a simpler substance?
WHY NOT???
Atom: Smallest part of an element that has the properties of that element.
Chemical symbol: Shorthand way to write the elements: Carbon ____ Hydrogen ____ Calcium ___ Gold ____
Atom: Smallest part of an element that has the properties of that element.
Chemical symbol: Shorthand way to write the elements: Carbon ____ Hydrogen ____ Calcium ___ Gold ____
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Elements and Compounds Notes 2016.notebook January 15, 2019
Compound: Two or more elements chemicallycombined
Carbon + Oxygen = Carbon Dioxide= CO2
Hydrogen + Oxygen = Water= H2 O
Sodium + Chlorine = Sodium Chloride= NaCl
Elements Compound
Na Cl
Properties of the elements are very different than properties of the compound itself.
Highly reactive! Poisonous! We put on food!
https://www.youtube.com/watch?v=ODf_sPexS2Q
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Elements and Compounds Notes 2016.notebook January 15, 2019
Compounds: Pure substances made of more than one elementWater = Carbon dioxide =
Molecules: Pure substances: 2 or more atoms chemically bonded together.
2 atoms of oxygen = O2
2 atoms of chlorine = Cl2Molecule but not compound!! (same element)
2 atoms hydrogen + one of oxygen = H2 OMolecule and compound!!
Chemical Formula: Combinations of chemical symbols to represent chemical substances. Ammonia = NH
Rubbing Alcohol = C H OH
Coefficient: Large number in front that tells you how many of that formula
3 7
3
2H2O
Ammonia Elements:
Alcohol Elements:
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Elements and Compounds Notes 2016.notebook January 15, 2019
Where is Subscript placed: to right of element symbol
What does Subscript tell you? The number of atoms of element in the compound
When there's only One atom, the subscript 1 is ______ written.
Coefficient: Large number in front that tells you how many of that formula
Subscript
2H2O
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Elements and Compounds Notes 2016.notebook January 15, 2019
Chemical Formula for Carbon Dioxide
How many atoms of carbon? _____ oxygen? ____
If chemical symbols are like letter, and chemical formulas
are like words, chemical equations are like SENTENCES!
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Elements and Compounds Notes 2016.notebook January 15, 2019
Chemical Equation: Shorthand method to describe chemical reactions using chemical formulas and other symbols
C + O2 CO2
Chemical Equation for Carbon Dioxide
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Elements and Compounds Notes 2016.notebook January 15, 2019
The Law of Conservation of Mass:The mass of all substances BEFORE a chemical reaction is the SAME as AFTER the chemical reaction!
(Count the atoms!)
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Elements and Compounds Notes 2016.notebook January 15, 2019
Does this reaction show Law of Conservation of Mass?
Learn to Count Atoms!
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Elements and Compounds Notes 2016.notebook January 15, 2019
LET'S PRACTICE COUNTING!
2.
3.
4.
5.
CarbonOxygen
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Elements and Compounds Notes 2016.notebook January 15, 2019