Unit3Day1-Crawford Tuesday, October 08, 2013 3:43 PM Vanden - - PDF document

CH301 Vanden Bout/LaBrake Fall 2013

Vanden Bout/LaBrake/Crawford CH301 WHY IS EVERYTHING SO DIFFERENT? UNIT 3 Day 1

CH301 Vanden Bout/LaBrake Spring 2013

Important Information

EXAMS SHOULD BE GRADED BY MIDDAY SATURDAY HW…. DEPENDS ON HOW DAY GOES….

Unit3Day1-Crawford

Tuesday, October 08, 2013 3:43 PM Unit3Day1-Crawford Page 1

CH301 Vanden Bout/LaBrake Fall 2013

What are we going to learn today?

Think about why matter is so diverse Attractive and Repulsive Electrostatic Forces Dipole Moment

CH301 Vanden Bout/LaBrake Fall 2013

POLL: CLICKER QUESTION 1

Matter is diverse implies all of the following, EXCEPT: a) The same type of matter can exist in different phases b) Different types of matter exist in different phases at the same temperature c) Compounds exhibit different characteristic properties based on the type of elements that compose that compound d) All matter is composed of the same fundamental building blocks

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CH301 Vanden Bout/LaBrake Fall 2013

Work individually for 10 minutes to complete the worksheet PLEASE DO NOT TALK DURING THIS TIME WE WILL BE COLLECTING THESE WORKSHEETS!

CH301 Vanden Bout/LaBrake Fall 2013

Look Around

• Find three different types of matter
• Articulate why you think the matter is different from a

macroscopic observation and a molecular view of the substance

• Obvious that matter is diverse. Scientists have worked

hard to develop models to explain and predict the various forms of matter.

Share: What is an important factor in different types of matter being different?

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CH301 Vanden Bout/LaBrake Fall 2013

Share: What is an important factor in different types of matter being different?

CH301 Vanden Bout/LaBrake Fall 2013

Electrons are Important

• Electrostatic Attractions and Repulsions - Forces that

dominate on the molecular scale

• Can we get some electrons from some where and see for
• urselves
• Play with Scotch tape

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CH301 Vanden Bout/LaBrake Fall 2013

SET UP YOUR TAPE WHEN FINISHED

CH301 Vanden Bout/LaBrake Fall 2013

Based on your observation of the tape: a) The bottom is negatively charged b) The top is negatively charged c) It is impossible to tell which is negative

POLL: CLICKER QUESTION 2

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CH301 Vanden Bout/LaBrake Fall 2013

Press your tape down on your desk as indicated. Gently peel the B and T tape up off the base, keeping the pieces together. When directed rip the two pieces of tape apart. Don’t touch the tape to anything. Slowly bring the two pieces together. Observe Slowly bring a B tape near a neighbor’s B tape. Observe. Charge a balloon. Bring each tape near the balloon to see what happens.

CH301 Vanden Bout/LaBrake Fall 2013

Can you attract a liquid with a charged object? TRY IT!

MOLECULES CAN CARRY A WEAK CHARGE THE GREATER THE CHARGE THE STRONGER THE ATTRACTION TO THE CHARGED ROD! WHAT CAN YOU INFER FROM THE BURET EXPERIMENT CONCERNING THE RELATIVE

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CH301 Vanden Bout/LaBrake Fall 2013

MOLECULES CAN CARRY A WEAK CHARGE THE GREATER THE CHARGE THE STRONGER THE ATTRACTION TO THE CHARGED ROD! WHAT CAN YOU INFER FROM THE BURET EXPERIMENT CONCERNING THE RELATIVE CHARGE ON THE LIQUIDS?

CH301 Vanden Bout/LaBrake Fall 2013

Electrons are not always equally shared

Some atoms of elements have a stronger attraction for electrons than others – property is called Electronegativity Characterize Bonding more Quantitatively Using a Dipole Moment Measurement Intermediate situation – polar covalent Equal attraction – pure covalent

Electronegativity

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Electronegativity

CH301 Vanden Bout/LaBrake Fall 2013

Measure the Dipole Moment

DIPOLE MOMENT  μ μ = Q r Units: Debye (D) 1 D = 3.336 10–30 (C x m)

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CH302 Vanden Bout/LaBrake Fall 2012

DIPOLE MOMENT  μ μ = Q r Units: Debye (D) 1 D = 3.336 10–30 (C x m)

CH301 Vanden Bout/LaBrake Fall 2013

DIPOLE MOMENTS OF SOME COMMON COMPOUNDS HF 1.83 D HBr 0.8 D NaCl 9.0 D (gas phase) Given the following dipole moments: HF 1.83 D HBr 0.8 D NaCl 9.0 D (gas phase)

POLL: CLICKER QUESTION 3

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CH301 Vanden Bout/LaBrake Fall 2013

Given the following dipole moments: HF 1.83 D HBr 0.8 D NaCl 9.0 D (gas phase) Which of the following is a good guess for the dipole moment of HI? a) 0.4 D b) 1.4 D c) 2.4 D d) 4.0 D

POLL: CLICKER QUESTION 3

CH301 Vanden Bout/LaBrake Fall 2013

Dipole Moment

GUESS THE DIPOLE MOMENT OF O=C=O

If the dipole moment of CH3Cl is 1.87 Guess the dipole moment for: CCl

POLL: CLICKER QUESTION 4

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CH301 Vanden Bout/LaBrake Fall 2013

If the dipole moment of CH3Cl is 1.87 Guess the dipole moment for: CCl4

POLL: CLICKER QUESTION 4

CH301 Vanden Bout/LaBrake Fall 2013

Shape Matters –

Go from a 2 dimensional model to a 3 dimensional shape Take a look at Cl2 Take a look at HCl Take a look at CO2

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CH301 Vanden Bout/LaBrake Fall 2013

What have we learned?

Electrostatic Forces Dominate on the Molecular Level We have observed Electrostatic Forces Solids/Liquids/Gases – Something to do with the Forces Depending on how the electrons are dispersed in a bond, may or may not be polar Shape matters

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CH301 Vanden Bout/LaBrake Fall 2013

Learning Outcomes

Recognize that matter is diverse and the condensed phases of matter will vary based on composition Identify polar bonds Understand the concept of the bond and a dipole Define dipole moment

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