Lab 7: Flame Tests

 Pre-Lab

1. Ground state is when the electrons are in the lowest energy levels available. Excited state is when atoms absorb energy and "jump" to a higher energy level.

2. In this case, emit means the discharge of energy when the atom transitions back from its excited state to the grounded state.

3. The atoms are getting their excess energy from the heat.

4. Atoms emit light at different wavelengths. These different wavelengths represent different colors. Also, different atoms have different numbers of levels and electrons.

5. It is necessary to clean the nichrome wires between each flame test because the chemicals from the prior test can affect your results by altering the actual color of the chemicals under the flame test.

Summary

 In this lab we had popsicle sticks dipped into different chemicals and solids. Then, we put the popsicle stick over the flame and the flame changed color. We recorded this change of color next to the chemical name. Overall, I believe the purpose of the lab was to show how the different elements' excited atoms emit their varying energies. I also believe that this lab emphasized that different colors are unique to one substance as shown by the identifying the unknown substances exercise part of the lab.

Flame Tests

 LiCl- Red/pink
 NaCl- Orange
 SrCl₂- Red/orange
 CuCl₂- Blue/green (cyan)
 KCl- Violet
 FeCl₃- Sparks
 CaCl₂- Orange
 ZnCl₂- Orange


Unknowns

 The first unknown was Lithium Chloride and the second unknown was Potassium Chloride. We know what the unknowns are because when atoms get heated, they get into an excited state. Then they emit different wavelengths which are converted into different colors of light. So, when we put the unknown substances under the flame test, they emitted the same colors as Lithium Chloride(red/pink) and Potassium Chloride(violet) which is how we knew what the unknown substances were.

This is a picture of the flame test for CuCl₂

Lab 8: Electron Configuration Battleship

 The biggest challenge I had while playing was finding the electron configuration of the elements. Through playing electron battleship, I got a better understanding of how to do electron configuration of elements through the periodic table and electron configurations in general.

This is a picture of my setup

   This is a picture of my partner Elie's setup

Lab 6: Mole-Mass Relationships Lab

Purpose

The purpose of this lab was a representation of mass to mass relationships that exist in a chemical reaction. This lab also helped us practice to calculate and understand limiting reactants, theoretical yields, and percent yields.

Data

Mass of evaporating dish-28.98 g
Mass of evaporating dish + NaHCO ₃ - 31.01 g
Mass of NaHCO ₃ - 2.03 g
Volume of 6 M HCl- 15 mL
Mass of evaporating dish + remaining (solid) product- 30.31 g
Mass of remaining solid product- 1.33 g

Possible sources of Error

The possible sources of error included popping as this would reduce the mass and, hence percent yield. Also, the shape of the beaker was another source of error. The beaker was cylindrical while the evaporating was more like a bowl. Therefore, the cylindrical beaker would be a downfall because the water would condense on the sides and fall back in.

This is a picture of my work and answers for numbers 1-4. To clarify number 1: Because it has a higher molar mass which means that there would be less moles than the others.

Lab 5B: Mole-Mass Relationship Lab

Data

Mass of evaporating dish- 1.32 g

Mass of evaporating dish + Hydrate- 2.16 g

Mass of evaporating dish + anhydrous salt- 1.96 g (1st heating)

                                                                      1.84 g (2nd heating)

                                                                      1.79 g (3rd heating)

Calculations

1. 2.16g - 1.32g = 0.84g (mass of hydrate used)

2. 1.79g - 1.32g = 0.47g

    0.84g - 0.47g = 0.37g (mass of water lost)

3. (0.37g/0.84g) * 100 = 44% (percentage of water in the hydrate)

4. Percent Error = |44-36|/36 x 100

    Percent Error = 22% error

5. CuSO₄* 7H₂O

Since our percent error was very high(22%), the empirical formula above is not correct. Since the percentage of water in the hydrate was higher than the accepted value(36%), the ratio would most likely be lower than 7.

Hydrate prior to heating

Hydrate after heating

Lab 5A: Mole Baggie Lab

 The purpose of the lab was to figure out what type of compound the substance in the ziplock bag was. This lab made us practice our skills in finding the molar mass, number of moles, and identifying the type of compound just by knowing a few pieces of information. Our first bag's label was A2 and we identified it as Potassium Sulfate. Our second bag's label was B6 and we identified it as Zinc oxide.

Lab 4A: Double Replacement Lab

 Writing the net ionic equations challenged me a lot. I was also confused at first when I was trying to write the balanced chemical reactions, but after writing some of the reactions, it became easy.

This is a picture of my balanced chemical reactions for all of my reactions. NR beneath a reaction means no reaction.

This is a picture of my net ionic equations.

This is a picture of my micro-well plate.

Lab 3: Nomenclature Puzzle

 The goal of this activity was to put together a puzzle by forming formulas with compounds and matching the compounds with their respective formulas. The biggest challenge of this puzzle was the organization part. First, my group tried to divide everyone up by element. This plan backfired because many of the pieces overlapped. Therefore, we had to find the pieces we were looking for. At some times, this took us a long time to do as all of the pieces were scattered. I believe I contributed to my group the most by finding pieces and help to form a portion of the puzzle.