CHEM 2 LAB REPORTS



AP CHEM LAB REPORTS

TITLE PAGE:

Name of experiment: The Density of Solids and Liquids

No. of the experiment: Experiment no. 1

Name: Larry Laboratory

Course: Chemistry AP

School: Jefferson Township High School

Date: (Date completed)

On the next page, use the following headings for the report:

ABSTRACT: A short paragraph summarizing what was performed, including the concluding results.

EX: The relationship between absorbance of electromagnetic radiation at 620nm and concentration of copper(II) nitrate was studied with a Spectronic 20 in order to determine the percent of copper in 22-shell brass casings. Concentration and absorbance was found to be linear, in perfect correspondence to Beer's law. The average percent of copper was graphically determined to be 68.32%.

APPARATUS: Draw and label apparatus two-dimensionally. For example, draw and label first-time use of the Mettler analytical balance, the Buchner funnel, the vacuum pump, the Spec. 20, distillation equipment, a schematic circuit for electrical experiments, etc. You make take photographs of apparatus using your cell phone and incorporate those into your final lab report.

MATERIALS: Include a list of all consumable and non-consumable materials used in the lab.

THEORY: Briefly develop underlying principles or theory.(1-4 paragraphs)

EX: One general type of reaction involves the transfer of electrons, that is, the loss and gain of electrons. If electrons are lost, as in the case of metallic zinc, the process is named oxidation. If electrons are gained, as in the case of the hydrogen ions from the hydrochloric acid used in this experiment, the process is called reduction. Zn(s) causes the H+ to become reduced to H2(g), and therefore Zn is called the reducing agent. Conversely, the presence of the H+ causes the Zn to become oxidized to Zn2+, so H+ is named the oxidizing agent.

PRE-LAB ACTIVITY: Include a complete description of any pre-lab activities that were conducted. Answer pre-lab questions in this section.

PROCEDURE: Accurately describe how the experiment was performed.

DATA: (ALWAYS a separate page) Very neatly arranged in tabular form, often spreadsheet tables with your values highlighted. Qualitative data may take the form of photographs taken during the lab or sketches of what was observed.

EX: sample 1 sample 2 sample 3

mass of crucible + CaCO3 (+/- 0.01g) 23.13 24.62 24.55

mass of crucible (+/- 0.01g) 22.06 23.04 etc.

mass of CaCO3 (+/- 0.02g) 1.07

final volume of acid (+/- 0.01cc) 28.76

initial volume of acid (+/- 0.01cc) 0.23

volume of HCl (+/- 0.02cc) 28.53

Temperature (+/- 0.1oC) 25.6

Pressure (+/- 0.1mm Hg) 755.9

percent HCl, calculated(+/- 0.01%) 37.2

percent HCl, true (+/- 0.01%) 39.1

Error 1.9

% Error 4.9

CALCULATIONS: Show calculations. Use only the data of the best trial. Neatly demonstrate the math set-ups. Show sample error calculations.

EX:

dacid = mass ÷ volume = (240.00 + 0.02g) ÷ (200.0 + 0.02cc) = 1.200g/cc + 0.02%

% acid = (18.5 + 0.1 g ÷ 50.0 + 0.1g) x 100 = 37.0% + 0.01%

% error = (O-A) ÷ A x 100 = 0.4 ÷ 12.5 x 100 = 3.2%

ANALYSIS: Fully answer all questions asked in the lab handout in complete sentences.

CONCLUSION: A great deal of attention is focused on your ability to write a sophisticated analysis of the lab. It should be a unified summary of your work on the topic under study. It should not be brief, fragmentary, expansive, or excessively critical of apparatus or equipment. Write the conclusion soon after completing it, and edit it a day or two later.

Under this heading, include:

1) accuracy and precision of results. Compare your answers to class averages and values.

2) how to improve the accuracy and the precision (assume that you have as much time (and possibly money!) as you need to accomplish this.

3) reasons for all errors.

4) the degree of significance or influence of particular errors upon the final result.

5) proofreading it before submitting it.

6) If the purpose of your lab was to determine something quantitatively, the final numerical result must be included.

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Please note that your formal lab report must be typed. However you will also be responsible for maintaining a bound lab notebook (which will be provided to you). In the bound book, you should write down your procedure as you complete the steps. You should include any significant observations about the lab. Your data must be written in your lab notebook. (Not copied from somewhere else - written down as you complete the lab! Your formal lab report is your chance to make it look pretty.) You should also include a preliminary sketch of any graphs that will be part of your final lab report.

These lab notebooks will be collected and checked at least once per marking period.

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