1. Solution Interactions and Solution Formation
How do solvent and solute interact when forming solutions?

2. Table of Contents Part 1: Critical Thinking Questions
Parts of a solution
More examples of solutions
Intermolecular forces
IMF in molecules and IMF in solutions
Interactions in solutions
How do IMF determine if a solution will form?
Sugar/water and Oil/water
Cleaning paint brushes
Part 2: Solution Formation
When the solute is covalent
When the solute is ionic
When the solute is an acid

3. Part One: Critical Thinking Questions
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4. Parts of a Solution Solvent Solute Solution Solvent Solute Solution
Question 1
Parts of a Solution
Solvent
Solute
Solution
Solvent
Solute
Solution
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5. More Examples of Solutions
Question 1
More Examples of Solutions
Solute
Solvent
Solution
Examples
Gas
Air (O2 dissolved in N2)
Liquid
Carbonated soda (CO2 in water), Swimming pool (Cl2 in water)
Wine (ethanol in water)
Vinegar (acetic acid in water)
Solid
Salt Water
Sugar Water
Dental amalgam for fillings (liquid mercury in solid silver)
Alloys (14 karat gold: solid silver and solid gold)
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6. What are Intermolecular Forces?
Question 2
What are Intermolecular Forces?
Intramolecular forces:
Forces between atoms which hold them together in molecules (i.e. chemical bonds)
Intermolecular forces:
Attractive forces between separate molecules, determines properties like state of matter, melting/ boiling point, volatility
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7. What Kinds of IMF Exist between Molecules?
Question 3
What Kinds of IMF Exist between Molecules?
Dispersion
Occurs between all covalent molecules
Temporary changes in electron distribution causes short lived polar attractions between normally nonpolar molecules
Dipole-dipole
Occurs between polar covalent molecules
Positive pole of one molecule is attracted to the negative pole of another molecule
Hydrogen bonding
Occurs between molecules with H—F, H—O, or H—N bonds only
Partially positive hydrogen of one molecule is attracted to the partially positive F, O, or N of another molecule
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8. What Kinds of IMF Exist in Solutions?
Question 4
What Kinds of IMF Exist in Solutions?
Three kinds:
Solute-solute (attractions between solute particles)
Solvent-solvent (attractions between solvent particles)
Solute-solvent (attractions between solute and solvent particles)
In order for a solution to form:
Solvent-solvent
and
Solute-solute
interactions
<
Must be weaker than
Solute-solvent interactions
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9. Color Code Each Interaction
Question 5
Color Code Each Interaction
Now you color in the rest.
Solute-solute interactions
Solvent-solvent interactions
Solute-solvent interactions
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10. How do IMF Determine if a Solution will Form?
Question 6
How do IMF Determine if a Solution will Form?
Solutions form when the solute-solvent interactions overcome the solvent-solvent and solute-solute interactions
This only occurs when the solute and solvent are able to interact very strongly with each other – this occurs when solvent and solute have similar polarities.
Water has regions of positive and negative charge – it’s polar!
This fatty acid (from olive oil) is pretty much all nonpolar.
Because water is polar and oil is nonpolar, they cannot interact, and do not dissolve. Remember: like dissolves like.
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11. Question 7
Sugar and Water
Glucose is a polar covalent molecule, meaning each glucose molecule has charges (which allow it to interact with water and dissolve).
Draw your solution showing the solvent-solvent, solute-solvent, and solute-solute interactions for sugar water.
Remember, opposite charges attract while like charges repeal. G O H
Glucose, a sugar molecule
Water, a polar solvent
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12. Question 8
Oil and Water
Oil is a nonpolar molecule while water is a polar molecule. These different polarities mean that water and oil do not interact enough to form a solution.
Draw your solution showing the solvent-solvent, solute-solvent, and solute-solute interactions for oil and water.
Remember, oil and water do not strongly interact. O H
Oil
Oil, a nonpolar molecule
Water, a polar solvent
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13. Part Two: Solution Formation
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14. When Polar Covalent Molecules Dissolve
Question 9
When Polar Covalent Molecules Dissolve - G G - G G + + G G G + - G G - G +
Glucose (Sugar)
Cube G
Glucose is a polar covalent molecule with lots of positive and negative charges.
When many glucose molecules are bonded together, they for a glucose crystal, such as a sugar cube. G
Glucose Molecule
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15. When Polar Covalent Molecules Dissolve
Question 9
When Polar Covalent Molecules Dissolve
Click to add the glucose to the water.
This process is simply referred to as dissolving. G G
Notice that the sugar is still a molecule – the atoms didn’t break apart. G G
Before G G
After G G G G G G
The water molecules surround the glucose, based on charge. G G G
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16. When Ionic Substances Dissociate
Question 9
When Ionic Substances Dissociate
Ionic substances, such as NaCl, are made of cations and anions. +1 -1 +1 -1 +1 -1 +1 -1 +1
They already are made of charges.
Before Adding to Water +1
Sodium Cation -1
Chloride Anion
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17. When Ionic Substances Dissociate
Question 9
When Ionic Substances Dissociate
Click to add the NaCl to the water.
After Adding to Water
Once the ions break away from the crystal, water molecules surround them based on charge. + - + - - +
Before Adding to Water
Once the salt is added, water molecules begin colliding with the salt crystal. + - + - + - + - +
This process is called dissociation, because the charges in the ionic substance already exist, they just need to break apart (dissociate) from each other. + - + - + - + - +
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18. HCl has partial charges, it does not have full charges.
Question 9
When Acids Ionize
When added to water, the water molecules will collide with the HCl molecules, causing the HCl atoms to become fully charged (ionized) as they form solution.
HCl is a polar molecule. The chloride “pulls” much harder on the shared electrons, causing unequal sharing. Cl H δ+ δ-
HCl has partial charges, it does not have full charges.
This is due to the differing electro negativities of the atoms – Cl is more electronegative than H.
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19. - - When Acids Ionize + + (HCl is a liquid) Before Adding to Water
Question 9
When Acids Ionize + - H Cl H Cl - +
(HCl is a liquid)
Before Adding to Water
After Adding to Water
When water collides with the HCl, some electrons are switched around, leading to the formation of ions. This is called ionization, because new ions are formed.
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