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Quick recap of yesterday’s demo http://

www.youtube.com/watch?v=jJvS4uc4TbU

Homework

On page 157 is the reading in green Sidebar “The Chemistry of Fireworks”

Notes and Summary

Starting on page 156-157 Reflect and Connect #1-5 Question and Answers written

Both in Complete Sentences Complete sentences do NOT begin with

“Yes,…..” or “No, ……”

Reflect and Connect pg 156 1. How are the flame tests similar to fireworks?

How are they different? 2. How could you use flame tests to organize

metallic elements found on Earth? 3. What differences among the atoms of

sodium, potassium, strontium, calcium, and copper could lead to differences in flame test colors?

4. Why doesn’t water produce color in a flame test?

5. What questions do you still have regarding how some atoms produce color in a flame?

Reflect and Connect pg 156 1. How are the flame tests similar to

fireworks? How are they different? Both the flames from the demo and the flames

from fireworks must contain enough energy to cause some sort of change in the metal ions placed in either flame.

This change in the metal ions gives off light of colors that are only found with the metal in question.

Fireworks displays multiple colors, while the flame tests show only one color. This is probably due to fireworks containing more than one metal in them.

Reflect and Connect pg 156 2. How could you use flame tests to

organize metallic elements found on Earth? Flame test colors could be used to categorize

metallic elements by grouping them according to colors. Ex: all metals with yellow flame test might

form one group and all metals with a red flame test could form another

This type of organization does not match the periodic table of the elements and that is why it’s not used

Reflect and Connect pg 156 3. What differences among the

atoms of sodium, potassium, strontium, calcium, and copper could lead to differences in flame test colors? The metal atoms used in this demo are

different in their physical properties such as hardness, melting point, and density. Each atom has a different number of protons and electrons.

Reflect and Connect pg 156 4. Why doesn’t water produce color

in a flame test? The water doesn’t produce color because

whatever it is that that the flame does to the metal ions, it does not do to water.

The energy of the flame was not enough energy to produce color. We don’t yet know the exact reason for producing color.

There is a difference in ionization energies between water and the metal ions

Reflect and Connect pg 156 5. What questions do you still have

regarding how some atoms produce color in a flame? Why don’t chloride ions produce color? Do any negative ions produce color in a

flame? Do the metal ions react with compounds

in the air to make color?

EMITTING TO THE TRUTHExplore

EMITTING TO THE TRUTH

Update your TOC:

EXPLORE: EMITTING THE TRUTH

Start your new Header Page on the RIGHT SIDE of your notebook.

Learning Target: • I will begin to understand what color tells us

about the underlying structure of matter• I will understand how the atomic structure can

relate to flame colors.

Different elements an their spectra lines

http://chemlinks.beloit.edu/BlueLight/moviepages/ab_em_el.htm

Emitting to the Truth

Read the Introduction p. 158 & 159

Emitting to the Truth We are going to be looking at different sources of

light. Incandescent light bulb:

an electric light produces light with a filament wire which is

heated to a high temperature by an electric current passing through it.

Which makes it glow Continuous spectrum All wavelengths are present in the light that is

emitted.

Emitting to the Truth

fluorescent light bulb: an low pressure gas filled lamp

that uses fluorescence to produce visible light.

produces thin line spectra with some continuous spectra between the bright lines.

Emitting to the Truth

sunlight: a portion of the electromagnetic

radiation given off by the Sun Particularly:

infrared, visible, and ultraviolet light.

Emitting to the Truth

We will be using a spectroscope, which is an instrument that separates light into its principal wavelengths.

Emitting to the Truth

The spectroscope will show the spectrum of colors that make up the light that is being studied. spectrum: the range of colors

observed when white light is dispersed through a prismSpectra is the plural of spectrum.

Emitting to the Truth

Each element has a unique spectrum.

Spectra are like fingerprints. Spectra are characteristic

properties of substances and can be used to identify an element.

Emitting to the Truth

Your spectroscope has a scale on it to show the wavelength of each color that makes up the light source.

The lines that appear are called spectral lines.

Emitting to the Truth

Wavelength Is the distance between the crests of

waves Determines the type of electromagnetic

energy

Emitting to the Truth Electromagnetic spectrum

Visible light is a small portion of the electromagnetic spectrum

The color depends on the wavelength

Emitting to the Truth

Let’s look at the spectra for different elements:

Emission Spectra of ElementsBeloit College Emission & Absorption Spectra

Light 1

Light 2

Light 3

Light 4

Emitting to the Truth

Fluorescent tubes contain specific elements… producing thin line spectra.

��Incandescent Light bulbs have a thin wire through which electricity runs and burns white-hot… like a campfire, or like the sun!

Remember that each color has a different wavelength, which means a different amount of energy…

Emission spectra can tell us about the �composition of objects… like stars for instance!

Energy: The Ultimate Quick Change Artist

Energy is the ability to do work Energy can be measured only by what it does Energy is abstract - you cannot see it but you

can detect it by the changes it effects Energy can cause changes in temperature,

height, velocity, bonds in a molecule, the state of an electron around an atom

Energy is not created or destroyed - it just changes forms

You observe energy changes which lead you to make conclusions about how energy is distributed.