UNIT 10- Solutions and Gases Lecture 3: Factors affecting ...chemistrykippnyc.weebly.com/.../genchem_unit12_lecture1_solubility.… · factors that affect solubility. For each slide

Monday, April 13, 2015 WELCOME BACK! Unit 12: Solutions! 12.1 Solubility

WHAT QUESTIONS DO YOU HAVE TO FROM BREAK WORK?

Binder HW for checking: ALL: BREAK WORK Juniors: completed Regents Exam Sophomores: EC

Notes: DO NOW

(Seat)

Chemistry Reference Table

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matter

Pure substance Mixture

Element Compound Homo-

geneous

Hetero-

geneous

Homo-

geneous

Solute

Solvent

This is the greatest thing ever invented. At the end of the lesson, you will tell me why the “solution” to

waterproof mascara is solved by this magical goodness.

Quick Practice

Solution Solute Solvent

NaCl (aq)

C6H12O6 (aq)

AgNO3 (aq)

NaCl Water!

C6H12O6 Water!

Water! AgNO3

Soluble/Insoluble? Dissolves or does not

dissolve? Homogeneous or Heterogeneous?

Soluble

Insoluble

Dissolves Homogeneous

Does not

dissolve Heterogeneous

VIRTUAL STATIONS

• The next two slides will take you through the factors that affect solubility. For each slide I want you to consider what the factor is (ex. Temperature, pressure, etc.) and the trend for solubility.

• THERE WILL BE NO TALKING, CALLING OUT, ETC. in this activity in order to give all students a chance to think about what they see!

VIRTUAL STATION: FACTOR 1

SCENARIO: Dissolving sugar in hot coffee versus iced coffee. Which dissolves more quickly?

VIRTUAL STATION: FACTOR 2

SCENARIO: Both of these bottles contain seltzer water. Which was is the gas less soluble in? THIS IS TRICKY!

VIRTUAL STATIONS DEBRIEF

FACTORS EFFECTS

TEMPERATURE The hotter the solvent, the more soluble the solute is.

PRESSURE FOR GASES ONLY! The higher the pressure, the more soluble the gas is.

Let’s talk exceptions.

FACTORS EFFECTS EXCEPTIONS

TEMPERATURE The hotter the solvent, the more soluble the solute is.

FOR GASES- Gasses are more soluble in colder solutions.

PRESSURE FOR GASES ONLY! The higher the pressure, the more soluble the gas is.

DOES NOT EFFECT SOLIDS OR LIQUIDS.

WHY?!

• When a solute dissolves in solution, it requires interaction between the solvent and the surface of the solute (IT NEEDS TO MIX TOGETHER!)

Question.

HOW IS THE PROCESS OF DISSOLVING DIFFERENT FROM COLLISION THEORY?

POLARITY

What is polarity?

Unequal sharing of electrons due to large difference in electronegativity.

What trends do you see?

Solute Type Nonpolar solvent Polar solvent

Non-polar Soluble Insoluble

Polar Insoluble Soluble

“LIKE DISSOLVES LIKE!”

How does polarity affect solubility?

FACTOR EFFECT EXCEPTIONS

POLARITY “Like dissolves like”

Ionic compounds

Critical Thinking

• Having more surface area makes something dissolve faster. Why is this not considered a factor that affects solubility?

– Powdered sugar vs. sugar cubes—both are the exact same chemical, sucrose, C12H22O11

• However, smaller particles are more likely to dissolve than large particles.

– Sucrose vs. Starch

– C12H22O11 vs. C200H400O200

Quick Practice

Solute Solubility Polar or non-polar

Oxygen (O2) Insoluble

Glucose (C6H12O6) Soluble

Hexane Insoluble

Nitrogen (N2) Insoluble

Does this make sense?

70% Isopropyl Alcohol 30% Water

Canola Oil Water

Why does the bear dissolve in water?

BECAUSE IT’S POLAR!

This knowledge basically solved 99% of the problems in my life.

The quest for the best mascara… calls for the best eye makeup remover.

Why do we care about this?!

Self-experimenting with waxing usually leads to chaos.

Classwork Time!

Closing summary

What four factors affect solubility?

temperature, pressure, and polarity, size of particles!

What increases solubility for liquids and solids?

Small particle size and high temperatures!

What increases solubility for gases?

Low temperatures, high pressure