01D Chemical Reaction Overview.notebook
April 07, 2016
What Happens During Chemical Reacons
Chemical reacons produce new substance through the rearrangement of the atoms.
The rearranged atoms combine to form new compounds with new properes.
Word Equaon
hydrocarbon + oxygen ‐‐> carbon dioxide + water
Skeleton Equaon
Balanced Equaon
01D Chemical Reaction Overview.notebook
April 07, 2016
New compounds form spontaneously because the rearrangement lowers the overall energy of the compound.
Some new compounds only form if you provide energy to cause the rearrangement.
dihydrogen oxide ‐‐‐> hydrogen gas + oxygen
01D Chemical Reaction Overview.notebook
April 07, 2016
When a chemical reacon occurs there is oen evidence that we can see.
Rearranging atoms can cause the following:
1. colour change
2. energy is released (heat, or light)
3. solid is formed from two liquids
4. bubbles form (a product is a gas)
5. difficult to reverse
(vit C clock reacon, form a precipitate)
01D Chemical Reaction Overview.notebook
April 07, 2016
01D Chemical Reaction Overview.notebook
April 07, 2016
Physical Change
Not all changes are chemical changes. Some mes maer can change without making a new substance. In this case the atoms are not rearranged and the properes of the substance stay the same.
Physical changes occur when a substance:
1) dissolves
2) melts
3) boils
4)freezes
Other changes like ripping paper, or breaking a window are also considered physical changes.
01D Chemical Reaction Overview.notebook
April 07, 2016
01D Chemical Reaction Overview.notebook
April 07, 2016
01D Chemical Reaction Overview.notebook
April 07, 2016
01D Chemical Reaction Overview.notebook
Represenng Atoms
Atoms are the basic building block of all maer. Each element is made of a unique type of atom.
carbon
12
6
lithium
7
3
C
Li
April 07, 2016
01D Chemical Reaction Overview.notebook
April 07, 2016
The structure of each atom follows a paern described by a Bohr‐Rutherford diagram. The neutrons, and protons are located in a densely packed, extremely ny nucleus, while the electrons are placed in orbitals outside of the nucleus.
electrons
The orbitals can hold specific numbers of electrons. Each electron has a different amount of energy depending which orbital it is located.
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draw then r
01D Chemical Reaction Overview.notebook
April 07, 2016
Reacvity of Atoms
Atoms react with other atoms by gaining, losing and sharing electrons. Only the electrons in the last orbital are involved in chemical reacons. We can predict how atoms will react based on their placement on the periodic table.
01D Chemical Reaction Overview.notebook
Large Atoms
• small force of aracon
• have low ionizaon energy and electron affinity
• loses electrons easily
Small Atoms
• large force of aracon
• have high ionizaon energy and electron affinity
• gain electrons easily
April 07, 2016
01D Chemical Reaction Overview.notebook
April 07, 2016
When a chemical reacon occurs it is only the outer most electrons that are involved.
We can simplify the BR diagram so that we only need to draw these outside electrons
Lewis Diagram
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each sid
01D Chemical Reaction Overview.notebook
April 07, 2016
Atoms vs. Ions
Atoms react in order to rearrange their electrons into a stable paern. One way to rearrange electrons is by losing or gaining electrons.
Of all the atoms, the noble gases have the most stable paern of electrons.
S
sulfur
Na
sodium
Atoms have a neutral charge (equal numbers of electrons and protons). When an atom loses or gains electrons it is no longer neutral.
01D Chemical Reaction Overview.notebook
April 07, 2016