LAB #5
Key Points
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Types of compounds
Types of bonds
Writing formulas
Solute Vs. Solvent
Conductivity
Ionic and Net Ionic Equations
Ionic Compounds
• Contain ionic bonds
• taking of electrons.
• Components have a large difference in electronegativity.
• How can we get this?
• Must contain a metal and a non-metal to obtain the large
difference in electronegativity.
• The bond has a positive side and a negative side.
• Metals loose electrons and non metals gains electrons.
• Example : Na+1+ Cl-1→ NaCl
Molecular Compounds
• Contain covalent bonds –
• sharing of electrons
small or no difference
in electronegativity
• Components have a
• Usually two non-metals; two types of bonding:
• (non-polar)
• (polar covalent)
Molecular Compounds with Non-Polar Bonds
• No difference in electronegativity
(diatomic elements)
• Br2 Br–Br
• Since both atoms are the same they have the
same pull on the electron.
Molecular Compounds with
Polar Covalent Bonds
• when the atoms are not the same:
• CO2
• slight difference in electronegativity
• The atom with the greater electronegativity will
have a slight -side
• The atom with the smaller electronegativity will
have a + side.
Ionic Compound
Metal & Non-metal
Molecular Compounds
(2 types)
Both 2 non-metals
Mg2++2Cl-1→ MgCl2
Br–Br ( non-polar)
Diatomic elements
H2O
(Polar covalent)
+H
H+
O-1
Remember + and – are not charges like ions,
they are slightly positive and slightly negative
sides of the compounds.
Things to Remember:
MgCl 2
Subscripts: tell
how many atoms
are present
1
Cl
Superscripts:
tell the charge
Formula Writing:
• (1) Write the names of the atoms
Sodium Chloride
• (2) Write the ions that they form:
Na+1 + Cl-1
• (3) Finally how they combine
Na1Cl1
• This gives us a set ratio
Examples:
• (1) Magnesium Chloride
• (2) Mg 2+ + Cl1• (3)
Mg1Cl2
• (1)Calcium Hydroxide
• (2) Ca 2+ + OH1• (3) Ca1(OH)2
Ratio
MgCl 2
•Tells us how many of each atom are present
•Once the ratio is set it can’t be changed
•Think of this ratio like a cookie recipe
•I can change how much is present by multiplying
The ratio like doubling a cookie recipe.
How many atoms are present?
MgCl 2
2MgCl 2
Mg = 1
Cl = 2
Mg = 2
Cl = 4
Ionic and Net Ionic Equations:
• Ionic: simply tell us what ions are present in the
equation.
• Ionic: only has ions
• Net: tells us which ions combine to form a solid.
Example: Not in Lab Book
Equation in words
Copper II Chloride + Magnesium Hydroxide yields
Magnesium Chloride + Copper (II) Hydroxide
Ionic Equation
Cu
2++2Cl1-
+ Mg
Note: 2(OH)
-1
2++
2(OH)1- → Mg
= (OH)
-1
+ (OH)
-1
2++
2Cl1 + Cu2+ 2(OH) 1-
Net Ionic Equation example:
Cu
2++2Cl1-
+Mg
2++
2(OH)1-→ Mg
2++
Ions
2Cl1- + Cu(OH)2
Solid
• Cu 2++ 2(OH) 1- → + Cu(OH)2
• Both Cu and OH are ions on the left, and they
form Cu(OH)2 solid on the right.
• MgCl2 is soluble (ions stay in solution)
• They are ions on the left and right
side of the equation.
Lab # 5
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Table A
Complete Table using data from demo
Table B
We will write the formulas for the following
compounds and determine if they are soluble in
water or Hexane.
Table C & Rest of Lab
Identify what is in the specific test tubes and
describe the result.
We will then write ionic and net ionic equations
for our reactions.
Ionic Equations (1)
Equation # 4 write equation # 1in ionic form
Na+1+Cl -1 + Ag+1+(NO3)-1 → Na+1 +(NO3)-1 + Ag+1
+ Cl -1
Equation # 5 write Equation #2 in ionic form
Mg+2+2Cl -1 + 2Na+1 + (CO3) -2 → Mg+2+(CO3)-2 +
Na+1+Cl -1
Ionic Equations (2)
2K+1 + (SO4) -2 + Na+1 + (NO3) -1
→ K+1 +(NO3) + 2Na+1 (SO4) -2
Net Ionic Equations pg 38 (1)
Ionic equationMg+2+2Cl -1 + 2Na+1 + (CO3) -2→ Mg+2+(CO3)2 +
Na+1+Cl -1
Net ionic equation Equation # 8
Mg+2 + (CO3) -2 → Mg(CO3)
Net Ionic Equations pg 38 (2)
• Ionic equation –
2K+1 + (SO4) -2 + Na+1 + (NO3) -1
→ K+1 +(NO3) + 2Na+1 (SO4) -2
• Net ionic Equation• All ions stay in solution.
• Use your chart for help, and remember that this
chart only applies to the products.
Pg 37 Equations Unbalanced
#1 NaCl + Ag(NO3) → Na (NO3) + AgCl
#2 MgCl2 + Na2(CO3) → Mg(CO3)+ NaCl
#3 K2(SO4)+ Na(NO3) → K(NO3)+ Na2(SO4)
Due Next Week
• Complete lab: pgs 34-36
• Complete homework and exercises: pgs 39-40