§2.3 Using chemical formulas

Planning for today
Chapter 2
§2.3
Using chemical formulas
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Planning for today
Chapter 2
§2.3
Using chemical formulas

Slide 1 - Diapositive

Slide 2 - Diapositive

Remember the particle model?
 

Slide 3 - Diapositive

Chemical Reactions...

Molecules are broken down and new molecules are formed.

A reaction can be written down as an equation or process:
molecules go in (reactants), different molecules come out (products).



 



Slide 4 - Diapositive

The periodic table;
the alphabet of
chemistry

Slide 5 - Diapositive

Het alfabet and the PT:

Alphabet
PT
Letter
Atom/Element
Word
Molecule
Sentence
Substance
Story
Materials
Atoms in a molecule are connected by atomic bonds (bonds between atoms)

Slide 6 - Diapositive

Slide 7 - Diapositive

d

Elements
Based on one kind of atom or molecules with one kind of atom (pure)


ggg
g


Compounds
Molecules containing more than one kind of atom.

Slide 8 - Diapositive

There are seven elements which always form molecules with two of their atoms. These are the BrINClHOF substances 
(Br, I, N, Cl, H, O, and F) 

Slide 9 - Diapositive

Molecules can be drawn but they can also be given a molecular formula.



Slide 10 - Diapositive

Naming compounds - Nomenclature, systematic

  1. First element of compound keeps its own name
  2. Second element gets -ide at the end 
  3. Greek numbering words are used to indicate how many of each element is in the formula
NO = nitrogen monoxide                      CCl = carbon tetrachloride 
  

Slide 11 - Diapositive

Greek:
number
mono-
1
di-
2
tri-
3
tetra-
4
penta-
5
hexa
6
hepta-
7
octa-
8
Name: index comes first
Formula: symbol comes first, followed by index
Never start a name with mono

Slide 12 - Diapositive

Practise:
Give the name:
1. N2O5
2. P2I4
3. S2Cl2


Give the formula:
1. phosphorous trichloride
2. nitrogen dioxide
3. diphosphorous pentaoxide

Slide 13 - Diapositive

Index and coëfficient
Methane is made up of one Carbon atom and four Hydrogen atoms. Its formula will be:
CH4
The 4 in methane is called an Index

If you have 2 methane molecules, you write it down as:
CH4 (and not C2H8)
The 2 before methane is called the coefficient



Slide 14 - Diapositive

Index and Coëfficient
The Index denotes how many atoms of one kind are WITHIN a molecule
C2H6

The coëfficient denotes how many molecules are present in a situation
2 HNO3 (Two Nitric acid molecules)

Slide 15 - Diapositive

Some practice
What atoms are one water molecule made up from? What is its formula? Does it have an index or coëfficient?

 

What atoms are sugar molecules made up from? What would you write down if you had three sugar molecules?

Slide 16 - Diapositive

Slide 17 - Diapositive

What atoms are water molecules made up from?
2 Hydrogen atoms, 1 oxygen atom
its formula is H2O
 

What atoms are glucose molecules made up from?
6 Carbon atoms, 12 Hydrogen atoms and 6 Oxygen atoms
If you have three of those molecules you write down:
3 C6H12O6

Slide 18 - Diapositive

Much used substances
Water, Ammonia, Carbon dioxide, Ethanol, Methane,
Sulfur dioxide, Sufuric acid
The diatomic elements: Br I N Cl H O F

Slide 19 - Diapositive

Slide 20 - Diapositive

Just a few more things!

Slide 21 - Diapositive

Molecules and atoms have mass
We weigh a certain amount, 

because

 the molecules and atoms we are made of weigh a certain amount!

Slide 22 - Diapositive

an Atom's mass is indicated in the Periodic table!

One Helium atom
weighs 4,003 u

u stands for Units 
of mass
1 u is equal to 0,00000000000000000000000166 grams 

Slide 23 - Diapositive

Slide 24 - Lien

Mass calculation
If water molecules consist of two hydrogen atoms and one oxygen atom they're mass is:


16,00 u + 2 x 1,008 u = 18,016 u


Slide 25 - Diapositive

All the molecules which you have been looking at you will use quite regularly so you will need to know the names and formulas of most of them by heart.

Slide 26 - Diapositive

Slide 27 - Diapositive

Moleculen en atomen zijn onzichtbaar klein. Als je zuiver water (H2O), zuivere alcohol (C2H6O) en keukenzout (NaCl) met elkaar in een glas mengt, krijg je een heldere, kleurloze oplossing.

Hoeveel soorten atomen zitten er in dat glas?
A
1
B
3
C
5
D
vele miljoenen

Slide 28 - Quiz

Moleculen en atomen zijn onzichtbaar klein. Als je een theelepel zuivere suiker oplost in een glas zuiver water, ontstaat een heldere suikeroplossing.

Hoeveel soorten moleculen zitten er in dat glas?
A
1
B
2
C
3
D
miljoenen

Slide 29 - Quiz

Verbinding
Element
H2
CH4
Cl2
HF
C6H12O6
Na

Slide 30 - Question de remorquage


A
separation
B
phase transition
C
chemical reaction

Slide 31 - Quiz


A
separation
B
phase transition
C
chemical reaction

Slide 32 - Quiz


A
separation
B
phase transition
C
chemical reaction

Slide 33 - Quiz


A
separation
B
phase transition
C
chemical reaction

Slide 34 - Quiz

Slide 35 - Vidéo

Slide 36 - Vidéo