Experiment 3A: Crystalistalization

How to approach a lab write up for EXP 3A

Name

Date (of experiment)

 

Title of experiment: (as listed in manual/handout)

 

Purpose or Aim: This says exactly what the goal of the experiment is. It may consist of one or more parts. Based on what is stated in the procedure, you should have a very good idea as to what the point of the experiment is. Explicitly and briefly state all in this section. (3 points)

 

Examples: 1. To recrystallize an impure sample of benzoic acid; 2. To determine the melting point of salicylic acid

 

Introduction: This explains the theory behind the experiment. Give some general background as to what the experiment is about. Include definitions of any key concepts that are an important part of the experiment.. (10 points)

This approach can be applied across all topics being covered.

 

Materials: List glassware, chemicals and equipment/instrumentation used in the experiment.

(5 points)

 

Pre-Lab Calculations (pg. 22): (5 points)

 

Procedure: Write a step by step procedure of the experiment as outlined in the video. Use a flowchart if possible (5points)

 

 

Results and calculations: Report results from experiment. Tables can be used, also show sample calculations. (10 points)

 

Mass of weight boat 1

Mass of weight boat 1 + impure sulfanilamide

Mass of impure sulfanilamide

Mass of weight boat 2

Mass of weight boat 2 + pure sulfanilamide

Mass of pure sulfanilamide

% Recovery

Melting point of pure sulfanilamide

Literature melting point of sulfanilamide

 

Discussion: Analyze the data you obtained in your experiment. Explain difference between the starting weight of the impure sulfanilamide and the pure sulfanilamide. (5 points)

 

Conclusion: (2 points)

 

Post lab calculations: (pg. 31)

 

Questions (1-3) (5 points)

Scientific Method and Atomic Structure

Week 1 Discussion: Scientific Method and Atomic Structure

Required Resources
Read/review the following resources for this activity:

  • Textbook: Chapter 1 and 2
  • Lesson
  • Minimum of 1 scholarly source

EBOOK: Bauer, R. C., Birk, J. P., & Marks, P. (2019). Introduction to chemistry. New York, NY:

Initial Post Instructions
The Discussions in this course are set up to deepen your understanding of the material as you make real-world connections and employ creative thinking. To get the most from these discussions, full engagement is expected on the part of the student. Be sure to stop by the discussion section frequently, not only to post but to read the postings of your peers and instructor. Engaging with your peers and learning together is key to this experience. For your initial post, choose one of the options below:

Option 1:
We will begin this topic by practicing the use of the scientific method. The steps of the scientific method are observation, hypothesis, experiment, results, and theory. Using your understanding of the scientific method from your readings and lessons, you will be applying this knowledge to a real-world situation. Take a real-world scenario in the news, or another outside source and apply the scientific method, being sure to detail the controls on your experiment.  Describe a result that would confirm your hypothesis.

Option 2:
Choose a scientific paper written in the last year.  The Chamberlain library is a great source for this.  For your chosen paper, look into the study and discuss how the scientific method was used in this paper.  Be sure to note they hypothesis, variables, results, etc.  Based on your understanding of the scientific method, be sure to discuss if you find this paper a trustworthy source and why.CHEM

Writing Requirements

  • Minimum of 2 sources cited (assigned readings/online lessons and an outside source)
  • APA format for in-text citations and list of references

Criteria

Initial Post Content: Addresses all aspects of the initial discussion question(s), applying experiences, knowledge, and understanding regarding all weekly concepts.

Evidence & Sources: Integrates evidence to support discussion from assigned readings** OR online lessons, AND at least one outside scholarly source.*** Sources are credited.*

Professional Communication: Presents information using clear and concise language in an organized manner (minimal errors in English grammar, spelling, syntax, and punctuation).

Notes

Credited means stating where the information came from (specific article, text, or lesson). Examples: our text discusses…., The information from our lesson states…, Smith (2010) claimed that…, Mary Manners (personal communication, November 2017)…

**Assigned readings are those listed on the syllabus or assignments page as required reading. This may include text readings, required articles, or required websites.

***Scholarly source – per APA Guidelines, only scholarly sources should be used in assignments. These include peer-reviewed publications, government reports, or sources written by a professional or scholar in the field. Wikipedia, Wikis, .com websites, or blogs should not be used as anyone can add information to these sites. For the discussions, reputable internet sources such as websites by government agencies (.gov) and respected organizations (.org) can be counted as scholarly sources. Outside sources do not include assigned required readings.

Pathway Determination Organic Chemistry Lab

Full Report / Pathway Determination

 

Note: The following are merely tips and guidelines to aid you in writing your report. It is not intended to provide a comprehensive or absolute check-list or outline.

 

1. Title: A few words describing the experiment or theme.

1. Abstract: As succinctly as possible describe:

· Purpose

· Method

· Results

In other words, what you were attempting to do, how you were attempting to do it, and what were the results. Limit the abstract to factual statements and do not include theory or analysis since these topics are covered in detail else ware. The entire abstract should be about 3 to 6 sentences.

1. Purpose and Theory

· Restate the purpose and if necessary provide more detail than in the abstract. For this particular experiment it would be very helpful to draw the chemical reactions in order to help explain the purpose.

· Draw all chemical reactions and label reactants and products with actual chemical names if known and/or in general terms (Reactant A,B…and Product C, D etc.) Drawing and labeling the reactions make it easy to refer to and discuss later. Products can be labeled as pyrazoles and pyrazolones etc.

· Provide a mechanism showing both possible pathways.

· Will a catalyst be used? Explain the purpose of the catalyst. It may be helpful to refer to your mechanism.

· Where in the mechanism is the path or course of the reaction determined.

· Is there any reason one path should be preferred over the other?

· How will the outcome of the experiment be determined? What specifically should you see in the data (MS, MP, IR, H-NMR, C-NMR etc.) that will allow you to conclude which pathway was selected?

1. Procedure / Experimental: In a concise manner and in your own words describe chronologically the procedure performed. Simply state what you did and do not explain why things were done.

1. Data and Calculations: This section should include all recorded measurements such as weights, physical constants (melting points, TLC, etc.) as well as any spectroscopic data such as IR. Calculations of percent yields should be shown and limiting reagents and balanced equations should be clearly indicated when relevant.

1. Discussion and Conclusions

· Give a conclusion that relates to the original purpose of the experiment.

· Interpret your data and explain how the data supports your conclusions and results. Be specific in analyzing the data by assigning the data as described by the professor making definite correlations between the chemical structure and the data.

· Was the yield high or low? Do you believe the product was pure or not and why? Make a clear argument for your conclusion based on the data. What is it about the data that leads you to conclude a certain product was formed versus another? What differences would you anticipate in the IR, C-NMR, H-NMR, MS, MP etc. if the pyrazole was formed instead of the pyrazolone or vice versa.

· Discuss any problems that you may have encountered and any differences from the expected outcome. Was the outcome reasonable and expected?

· In addition, you may comment on the experiment’s effectiveness in terms of achieving the goal such as answering the question the experiment was intended to answer. Did it produce the product in good yield and high purity? How do you know it was pure? If possible suggest alternative methods or procedures or ways in which the experiment could have been done better or improved etc.

1. References: This section is used to cite any sources you may have used for information. Include enough detail so that the reader can find and check the source.

General Chemistry

Isotopic abundance Calculation and Limiting reactions worksheet:

1. Naturally occurring magnesium has three isotopes with 12,13,14 and neutrons. Determine the mass numbers and write the symbols of these three isotopes.

2. Hydrazine is composed of 87.42% nitrogen and 12.58% hydrogen by mass. Its experimentally determined molar mass is 32.05 g/mol. Determine the empirical and molecular formulas of hydrazine.

Ans: Empirical Formula: NH3; Molecular Formula: N2H6.

3. A 63.47 g sample of an ionic compound contains 17.17 g sodium and 10.46 g nitrogen; the rest is oxygen. The compound’s molar mass is 84.99 g/mol. Determine its formula.  Ans: NaNO3.

Here Mass of Oxygen is not given. Thus, we can find as below and other process is simple as we did in other problems.

 

4. Write the balanced equation for the reaction that occurs when 23 grams of iron (II) chloride is mixed with 41 grams of sodium phosphate forming iron (II) phosphate and sodium chloride. If 16.1grams of sodium chloride are formed in the reaction, what is the percent yield of this reaction?

FeCl2  +  Na3PO4  →

5. Silver nitrate, AgNO3, reacts with ferric chloride, FeCl3, to give silver chloride, AgCl, and ferric nitrate, Fe(NO3)3.  In a particular experiment, it was plannned to mix a solution containing 25.0 g of AgNO3 with another solution containing 45.0 grams of FeCl3.

a.

a) Write the chemical equation for the reaction.

b) Which reactant is the limiting reactant?

c)  What is the maximum number of moles of AgCl that could be obtained from this mixture?

d)  What is the maximum number of grams of AgCl that could be obtained?

e)  How many grams of the reactant in excess will remain after the reaction is over?