ATOMIC EMISSION Formal Lab Report Guideline

Submit 7 pages in the following order:

1. - Cover sheet
2. - Theory and description of the experiment / procedure
3. - Table of data and results
4. - Graph
5. - Sample Calculations / Conclusion
6. - Answer to the questions
7. - Signed laboratory data sheet.

Single sided print document. −1 mark if double sided print. Extra page or missing page = −1 mark

You can use the following template if you whish

Page 1: Cover sheet

The first page must contain at least the following information.

• Student names (if joint lab report)
• Date the experiment was performed
• Lab section
• proper title

You can download and fill the following template if you whish.

Page 2: Theory and description of the experiment / procedure

Page 3: Table of data and results

You can use the laboratory data sheet It must be fully completed (any missing information will result in a penalty of 0.5 points).

Indicate at the top of the page the letter (or number) corresponding to the spectroscope used in the lab.
Complete the table of data. Calculate your average RH value with the %error.
If you make a joint lab report, both data sheet (signed by the teacher) must be submitted together.
No sample calculation in this page. Just data and results!

Page 4: Graph

• Plot the calibration curve for your spectrophotometer: wavelength (in nm) versus scale reading, using the data in Table 1.
• You can use Excel to create your own graph or download the provided templates.
• Enter your data into each of the two fitting models provided (polynomial and power-law).
• Use the R² value (closest to 1) and choose the best fit for your calibration curve (graph).
• Give this graph a relevant title, including the spectrophotometer number (or letter).
• Use the fitting equation to determine the wavelengths of the four spectral lines of the hydrogen atom.

Page 5: Sample calculations / conclusion

No need to type the formula, you can hand write (with a pencil) all the calculations
Include a short title (one line) before each calculation.

Always give a short one-line title for each calculation.
Use only use the red emission line to perform each of the following three sample calculations.
(Therefore, no need to write the sample calculations for the four emissions)
1- Wavelength determination: Use the “fit” equation of the graph to calculate the red wavelength.
2- Rydberg constant: Calculate the Rydberg constant (RH) for the red emission of hydrogen.
3- % error on RH for the red emission of hydrogen
4- Calculate the average RH value for the 4 hydrogen emissions together.

Page 6:Answer to the questions

Page 4 : Answers the questions Question 1 Calculate the Rydberg constant (RH) from the following hydrogen emission spectra experiment: Electron moving from n = 10 to n = 3 emits a photon in the infrared region at λ = 901.6 nm. Question 2 If an excited Be3+ ion with an electron at n = 5 (initial state) absorbs a photon of λ = 290.8 nm: a. What is the energy of this photon in kJ/mol? b. To what n level (final) will the electron moves? (hint: the Rydberg equation cannot be used here, use the Bohr model of the atom).

Page 7: Laboratory data sheet

The page filled in the lab and signed by the teacher.
If you chose to make a common lab report, wark will be given to the name of the student present in the lab data sheet

Useful equations

$\mathrm{\%yield}=\frac{\text{actual yield (g)}}{\text{theoretical yield (g)}}\times 100\%$	actual yield = mass obtained in the lab theoretical yield = mass expected or calculated
$\mathrm{\%Atom\; economy}=\frac{\text{mass of the product (g)}}{\text{mass of all the reactants (g)}}\times 100\%$	the masses are based on the stoichiometric reaction not the actual masses obtained in the lab.

Marking scheme Atomic emission (on 15 marks)

−0.5: Name and date not in ink in the data sheet
−1.0: Wrong graph title
−0.5: Spectroscope letter missing
−1.0: Wrong fit (polynomial or power, use the highest r² value)
−1.0: Wrong data point
−0.5: Wrong sig.fig. final answer
−0.5: No unit final answer
−1.0: Any calculation error
−1.0: double sided printed
−1.0: extra page, missing page, pages submitted in wrong order

LABORATORIES QUESTIONS: Solution Stoichiometry

No need to answer the pre-lab and post-lab questions of the lab manual.
Only answer the following question and submit these with your report on page 2.

Consider the following chemical reaction:

1. For this experiment, 33.01 g of B₂O₃(s) react completely with an excess of sodium hydroxide. Calculate the theoretical yield of Na₃BO₃(s) (in grams) assuming a %yield of 100%. (with the correct number of sig. fig)
   
2. What would be the required mass of B₂O₃(s) to get 50.0 g of Na₃BO₃(s) if the yield of this reaction was 70.88%? Assume the sodium hydroxide to be in excess.

(To get a marks, all your work must be shown)