Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

flame test, Study notes of Chemistry

Hogeschool AntwerpenChemistry

You will measure wavelengths of each sample and then use the speed of light equation to determine the unknown chemical. However, in order to complete this lab ...

Typology: Study notes

2021/2022

Uploaded on 08/05/2022

jacqueline_nel
jacqueline_nel 🇧🇪

4.4

(242)

3.2K documents

1 / 9

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
!Name:!
!Date:! Period:!
Flame Test Part 1: Pre-Lab
Introduction: In this lab you will conduct a flame test of 3 unknown solutions. You will measure wavelengths of each sample and
then use the speed of light equation to determine the unknown chemical. However, in order to complete this lab you will need to
understand several mathematical equations and vocabulary. Before completing Parts 2-4, you MUST complete the pre-lab so you are
able to complete this assignment correctly and on time.
Vocabulary and Key Concepts: Explain these big ideas in complete sentences.
1. What do wavelength and frequency measure? How are these two ideas mathematically related? Wavelength measures the
distance between two peaks in a wave while frequency measures the number of times a wave repeats itself per unit time. These two
properties are related by the speed of light equation which says that c = λν. !
!
!
!
2. How can you find the energy of a wave? Once wave frequency has been calculated, wave energy can then be determined
using the wave energy formula, E = hν, where E is energy, h is Planck’s constant and ν is frequency.!
!
!
!
3. What is a flame test? What does the Law of Conservation of Energy have to do with this type of experiment? A flame test uses
the concept of electron excitation to identify an element. By adding energy to a sample and observing the specific wavelength light
that is produced, frequency and energy can be calculated. While the flame test relies on electron excitation to produce light, the light
emitted is a direct result of the Law of Conservation of Energy which states that energy can not be created nor destroyed but can
change forms. This applies to the flame test because as heat energy goes into the unknown solution, it is converted into light energy
which is the observable measurement.!
!
!
!
!
Electromagnetic Spectrum: Use color pencils or markers to shade and label the complete visible spectrum.
pf3
pf4
pf5
pf8
pf9

Partial preview of the text

Download flame test and more Study notes Chemistry in PDF only on Docsity!

Name: Date: Period:

Flame Test Part 1: Pre-Lab

Introduction: In this lab you will conduct a flame test of 3 unknown solutions. You will measure wavelengths of each sample and then use the speed of light equation to determine the unknown chemical. However, in order to complete this lab you will need to understand several mathematical equations and vocabulary. Before completing Parts 2-4, you MUST complete the pre-lab so you are able to complete this assignment correctly and on time. Vocabulary and Key Concepts: Explain these big ideas in complete sentences.

  1. What do wavelength and frequency measure? How are these two ideas mathematically related? Wavelength measures the distance between two peaks in a wave while frequency measures the number of times a wave repeats itself per unit time. These two properties are related by the speed of light equation which says that c = λν.
  2. How can you find the energy of a wave? Once wave frequency has been calculated, wave energy can then be determined using the wave energy formula, E = hν, where E is energy, h is Planck’s constant and ν is frequency.
  3. What is a flame test? What does the Law of Conservation of Energy have to do with this type of experiment? A flame test uses the concept of electron excitation to identify an element. By adding energy to a sample and observing the specific wavelength light that is produced, frequency and energy can be calculated. While the flame test relies on electron excitation to produce light, the light emitted is a direct result of the Law of Conservation of Energy which states that energy can not be created nor destroyed but can change forms. This applies to the flame test because as heat energy goes into the unknown solution, it is converted into light energy which is the observable measurement. Electromagnetic Spectrum: Use color pencils or markers to shade and label the complete visible spectrum.

Flame Test Basics: Complete the table below showing the Before , During and After steps of a flame test. Before Flame Test Ground State Li Atom During Flame Test Excited Li Atom After Flame Test Ground State Li Atom Draw the Bohr diagram for each step of the Flame Test What is happening to the electrons in the atom? Electrons occupy the lowest possible energy level Valence electron absorbs energy and becomes excited to the next energy level Excited valence electron returns to ground state and energy is released in the form of light Wavelength and Frequency: Find the wavelength and frequency of the four waves shown below. Line 1 Line 2 Line 3 Line 4 Wavelength 1000 nm 125 nm 500 nm 250 nm Frequency 1 s-1^ 8 s-1^ 2 s-1^ 4 s-

Wavelength Comparison:

  1. Draw each observed wavelength below. Flame Test Solution # Color Estimated Wavelength (nm) 1 Pink^ λ = 650 nm Flame Test Solution # Color Estimated Wavelength (nm) 4 Green^ λ = 530 nm Flame Test Solution # Color Estimated Wavelength (nm) 6 Yellow^ λ = 600 nm

Name: Date: Period:

Flame Test Part 3: Data Analysis

Flame Test Part 3 Objective: Frequency Equation: Starting with the Speed of Light Equation , rearrange the equation to isolate frequency (ν). Then define each variable, including units. Speed of Light Equation Frequency Equation Define Variables c = νλ ν = c λ ν = Frequency (s-1) c = Speed of Light (3000 nm/s) λ = Wavelength (nm) Energy Equation: Write the Wave Energy Equation , then define each variable, including units. Wave Energy Equation Define Variables E = hν E = Energy (kJ/mol) h = Planck’s Constant (40 kJ/mol) ν = Frequency (s-1) Calculations: Use your wavelength data from Part 2 to solve for frequency and energy of each sample. Make sure to show ALL of your work. Flame Test Solution # 1 Wavelength (nm) λ = 650 nm Frequency Calculation ν = c = 3000 λ 650 Wave Energy Calculation E = νh E = (4.61)(40) Frequency = ν = 4.61 s-1^ Wave Energy = E = 184.6 kJ/mol

Graph Analysis:

  1. Graph Wavelength (nm) vs. Energy (kJ/mol).

Energy (kJ/mol)

Wavelength (nm)

  1. What do you notice about the graph? The wavelength versus energy graph shows a decreasing linear relationship.
  2. What does this say about the electromagnetic spectrum? What end of the spectrum has high energy? Which end has low energy? This indicates that waves that have longer wavelengths have lower energies, while waves that have shorter wavelengths have higher energy. Element Identification:
  3. Determine the element is in sample by comparing your calculated energies to the known energy values given on the Visible Light Spectrum Card. Flame Test Solution Calculated Energy Values (kJ/mol) Known Energy Values (kJ/mol) Element

1 184.6 181.2 Lithium

4 226.4 228.6 Boron

6 200.0 279.1 Sodium

Name: Date: Period:

Flame Test Part 4: Fireworks and Flaming Pickles

Flame Test Part 4 Objective: Fireworks! Reading:

  1. What is the difference between incandescence and luminescence? Incandescent light is produced when a substance is heated until begins to glow. Luminescence is caused when energy is added to substance and light it emitted based on that element.
  2. How do the atoms in a firework produce light? LIght in a firework is produced by electrons absorbing energy and luminescing. Electrons travel from the original ground state into an excited state and produce light. Flaming Pickles: Watch the Flaming Pickles demonstration and answer the following questions?
  3. How is the flaming pickle similar to a firework? The glowing pickles are a modified flame test experiment where electrons are excited by energy which is then emitted as a colored light.
  4. Unlike a firework, which has a double fuse system, where is the energy for the flaming pickles come from? The pickle experiment uses electricity to excite the electrons.
  5. What happens to the atoms when energy is added? The valence electron becomes excited and jumps to the next orbital. However, the electron can not sustain this excited state so it falls back down and releases that energy in the form of light (Law of Conservation of Energy).
  6. How can you use information you learned in the Flame Test Lab and Fireworks! reading to determine the type of chemical used in each pickle? If you can determine the wavelength of light being emitted, then the chemical composition can be determined by calculating the frequency and wave energy.