1. Ch. 10.1 – Chemical Reactions
Intro to Reactions read: (p. 276 – 280)

2. A.Signs of a Chemical Reaction
Evolution of heat and light
Formation of a gas
Formation of a precipitate
Color change

3. B.Law of Conservation of Mass
mass is neither created nor destroyed in a chemical reaction
total mass stays the same
atoms can only rearrange
4 H
2 O
4 H
2 O
36 g
4 g
32 g

4. C. Chemical Equations
A+B  C+D
REACTANTS
PRODUCTS

5. C. Chemical Equations
p. 278

6. 2H2(g) + O2(g)  2H2O(g) D. Writing Equations
Identify the substances involved.
Use symbols to show:
How many? - coefficient
Of what? - chemical formula
In what state? - physical state
Remember the diatomic elements.

7. Diatomics: N2 O2 F2 Cl2 Br2 I2 H2 Start with element #7
Form a figure 7
There are 7 of them – include Hydrogen       

8. D. Writing Equations 2 Al (s) + 3 CuCl2 (aq)  3 Cu (s) + 2 AlCl3 (aq)
Two atoms of aluminum react with three units of aqueous copper(II) chloride to produce three atoms of copper and two units of aqueous aluminum chloride.
How many?
Of what?
In what state? 2 Al
(s)
+ 3
CuCl2
(aq)
 3 Cu
(s)
+ 2
AlCl3
(aq)

9. E. Describing Equations
Describing Coefficients:
individual atom = “atom”
covalent substance = “molecule”
ionic substance = “unit”
3CO2 
2Mg 
4MgO 
3 molecules of carbon dioxide
2 atoms of magnesium
4 units of magnesium oxide

10. E. Describing Equations
Zn(s) + 2HCl(aq)  ZnCl2(aq) + H2(g)
How many?
Of what?
In what state?
One atom of solid zinc
reacts with
two molecules of aqueous hydrochloric acid
to produce
one unit
of aqueous zinc chloride
and one
molecule of hydrogen gas.

11. Writing Word Equations
1. When one unit of beryllium chloride reacts with 2 units of silver nitrate dissolved water, the reaction yields one unit of aqueous beryllium nitrate and 2 units of silver chloride powder.
2. When one molecule of fluorine gas is put into contact with one atom of calcium metal at high temperatures, one unit of calcium fluoride powder is created.
3. Two units of sodium nitrate react with one unit of lead (II) oxide to produce one unit of lead (II) nitrate and one unit of sodium oxide.