Lab 7: Flame Test Lab

In this lab, we had to burn different compounds over a flame with a wooden stick and observe the color of light emitted.  We then used those recordings to identify two mystery chlorine compounds in the end.

Pre-Lab Questions:

1.  The ground state is the normal electron configuration of atoms or ions of an element, whereas the excited state is when atoms or ions in the ground state are heated to high temperatures and some electrons absorb energy and "jump" to a higher energy level.

2.  The word "emit" means to release.  Electrons emit light in the form of electromagnetic radiation as they return to ground state.

3.  In this experiment, the atoms are getting their excess energy from the bunsen burner flame, since the atoms are being heated at high temperatures, causing the electrons to absorb energy and jump to higher energy levels.

4.  Different atoms emit different colors of light because each atom will produce only one color (each atom is quantized).  Different atoms also have different electrons, and those electrons could jump to different energy levels, creating different colors.

5.  It's necessary to clean the nichrome wires (or, in this experiment, use a different stick each time) between each flame test to ensure that different compounds don't mix.

Unknown #1 was lithium chloride (LiCl) and unknown #2 was potassium chloride (KCl).  We found this because we compared the color burned to the other eight recorded color observations.  Unknown #1 burned a magenta color, shown above, which matched LiCl, and unknown #2 burned a light purplish color, which matched KCl.

Lab 8: Electron Configuration Battleship

The aftermath of Battleship with my partner Rachel

The biggest challenge I had while playing was naming the right electron configurations, especially in the f block and elements with exceptions.  As we continued playing, this became easier, and I felt more comfortable with naming the electron configurations using the noble gas shortcut in the end.

Lab 6: Mole-Mass Relationships

The purpose of this lab was to practice calculating theoretical yield and percent yield using the experimental data of a reaction of sodium bicarbonate and hydrochloric acid.  We also had to find the limiting reactant using the reaction NaHCO3 + HCl --> NaCl + CO2 + H2O by looking at the relationship of the reactants and products (how much product each reactant yielded).

Questions 1-4:

Our percent yield is lower than 100% most likely because some salt popped out during boiling or we didn't wait long enough for all the water to evaporate before weighing the dish.

The remaining solid in the evaporating dish after boiling.  The salt is a bluish color because the same dish
 was used in the copper sulfate hydrate lab, and the dish was probably not cleaned very well after use. It was
also interesting that the tongs left a yellow-greenish mark on the salt.

Lab 5B: Composition of a Copper Sulfate Hydrate Lab

Hydrate before heating:

Hydrate after heating:

Calculations for Questions 1-4

Question 5: The empirical formula we calculated for the hydrate was 1 CuSO₄ · 4 H₂O.  We predict that the coefficient for H2O will be slightly smaller, if not equal to the actual value since our percent error was so small (8.3%).

Lab 5A: Mole Baggie Lab

The purpose of this lab was to identify a mystery substance in a plastic baggie given only the mass of the empty bag and the number of moles/particles.  We determined the identity of the substance by first weighing the bag on the scale to find the total mass, and then subtracted the mass of the empty bag from that, which gave us the substance mass.  Afterwards, we calculated the molar mass by dividing the substance mass (in grams) by the number of moles in the substance.  For Set B, we were given the number of particles instead of moles, so we just converted it into moles and plugged that into the molar mass equation.  Finally, we matched the calculated answer with one of the given possible compounds using the periodic table.

Bag A4 contained calcium carbonate, and bag B3 contained potassium sulfate.

Lab 4A: Double Replacement Reaction Lab

Well plates after the reactions.  Plates 2-7 show
chemical reactions in which a solid precipitate formed.

Balanced chemical reactions #1-5 with net ionic equations

Balanced chemical reactions #6-10 with net ionic equations

The most surprising part of this lab was how easy writing the net ionic equations turned out to be.  I expected it to be more complicated, but taking the shortcut presented in class instead of writing out the complete ionic equations was a lot quicker and more convenient.  The most challenging part was looking up if certain compounds were aqueous or solid using the solubility rules.

Lab 3: Nomenclature Puzzle

The goal of this activity was to solve a binary and polyatomic ions puzzle by matching the ion formula to their name, using our newly learned knowledge of chemistry nomenclature!  The biggest challenge we encountered was combining the pairs of triangles to form bigger squares and chains.  This puzzle wouldn't have been possible without organization and teamwork, so I think my biggest contributions were helping separate the squares into categories of certain elements, combining single squares at the very beginning, and also looking up certain unknown ions in the lab book.

Our finished puzzle!