实验报告英文版
英文实验报告模板
Title:Investigation of [Experiment Name or Objective]Introduction:The purpose of this experiment is to [briefly state the objective of the experiment]. The experiment aims to explore [briefly mention the variables or phenomena being investigated]. This report will detail the experimental setup, procedure, results, and conclusions drawn from the data collected.Objective:To [restate the objective of the experiment in a clear and concise manner].Materials:- List all the materials used in the experiment, including equipment, chemicals, samples, and any other items.1. [Equipment Name] - [Model or Description]2. [Chemical Name] - [Concentration or Volume]3. [Sample Name] - [Quantity]4. [Other Materials] - [Description]Procedure:1. [Step 1: Describe the first step of the procedure in detail. Include all actions taken and any safety precautions.]2. [Step 2: Continue with the next step, ensuring all actions and observations are clearly described.]3. [Step 3: Proceed with the subsequent steps, maintaining the samelevel of detail and clarity.]4. [Step 4: Complete the procedure by detailing the final steps and any additional notes or observations.]Observations:- Record all observations made during the experiment, including any visual, auditory, or tactile information.- Include any measurements taken, data collected, and any other relevant information.Data Analysis:- Present the data collected in tables, graphs, or other appropriate formats.- Discuss the significance of the data and how it relates to the objective of the experiment.- Use statistical analysis where applicable, and explain the results.Results:- Summarize the findings of the experiment.- Compare the results with the expected outcomes or previous studies, if applicable.- Discuss any anomalies or unexpected results.Discussion:- Interpret the results in the context of the experiment's objective.- Explain any limitations of the experiment and how they may have influenced the results.- Compare the findings with those of other experiments or literature.- Discuss the implications of the results and their potential applications.Conclusion:- Restate the objective of the experiment.- Summarize the key findings and their significance.- State whether the objective was achieved and why or why not.- Suggest areas for further research or modifications to the experimental procedure.Appendix:- Include any additional information that supports the experiment report but is not essential to understanding the main points.1. [Table of raw data]2. [Graphs or charts]3. [Photographs or diagrams]4. [Additional calculations or analyses]References:- List all the sources cited in the report, following the appropriate citation style.1. Author, A. (Year). Title of the work. Journal Name, Volume(Issue), Page range.2. Book Title (Edition). Author, A. (Year of publication). Publisher.3. Website Name. (Date of access). URLAcknowledgments:- Acknowledge anyone who assisted with the experiment, provided equipment, or contributed to the research in any way.Author Information:- Name of the author(s)- Affiliation- Contact informationDate:- Date of submission or completion of the experiment---This template can be adapted to fit the specific requirements of the experiment and the educational institution. The length of the report should be tailored to the complexity of the experiment and the depth of the analysis required.。
型式实验报告英文
Abstract:This report presents the findings of an experimental study conducted to determine the shear strength of concrete beams under various loading conditions. The objectives of the study were to evaluate the influence of different parameters such as beam size, reinforcement ratio, and loading patterns on the shear behavior of concrete beams. The experimental setup, materials used, testing procedures, results, and discussions are provided in detail in this report.1. IntroductionConcrete beams are widely used in structural engineering for their strength and durability. Shear failure is a common mode of failure in concrete beams, and understanding the shear strength is crucial for the design and safety of structures. This study aims to investigate the shear strength of concrete beams under different loading conditions to provide valuable insights for engineers.2. Experimental Setup2.1 Materials:- Concrete: The concrete mix used was a typical cementitious material with a compressive strength of 30 MPa.- Reinforcement: High strength steel rebars were used with a diameter of 12 mm.- Aggregate: River sand and crushed stone were used as fine and coarse aggregates, respectively.2.2 Beam Design:The beams were designed with a span of 600 mm and a depth of 150 mm. The width of the beams varied to study the effect of beam size on shear strength. Three different widths were considered: 100 mm, 150 mm, and 200 mm.2.3 Reinforcement Layout:The beams were reinforced with a reinforcement ratio of 0.6% for all sizes. The rebars were placed in two layers, with a spacing of 50 mm from the top and bottom surfaces of the beam.2.4 Testing Equipment:- Universal Testing Machine (UTM): To apply the load and measure the shear force.- Shear Load Apparatus: To apply the shear force to the beam.- Digital Load Cell: To measure the applied load.- Data Acquisition System: To record the load and displacement during testing.3. Testing Procedures3.1 Sample Preparation:The beams were cast in molds and cured for 28 days before testing. The beams were then demolded and allowed to acclimate for another 7 days before testing.3.2 Shear Test:The beams were loaded in a UTM with the shear force applied using a shear load apparatus. The loading rate was maintained at a constant rate of 0.1 mm/min until failure.3.3 Data Collection:The load and displacement were recorded at regular intervals using a data acquisition system. The maximum load and corresponding displacement were noted as the failure load and failure displacement, respectively.4. Results and Discussions4.1 Shear Strength vs. Beam Size:The results showed that the shear strength increased with an increase in beam width. This can be attributed to the increased effective cross-sectional area of the beam, which allows for a higher load-carrying capacity.4.2 Shear Strength vs. Reinforcement Ratio:The study revealed that the shear strength was influenced by the reinforcement ratio. An increase in the reinforcement ratio resulted in an increase in the shear strength. This is because the reinforcement provides additional tensile strength to resist the shear forces.4.3 Shear Strength vs. Loading Pattern:The loading pattern also had a significant impact on the shear strength. The results showed that a concentrated load at the midspan resulted in a higher shear strength compared to a uniformly distributed load. This is because the concentrated load leads to a higher stress concentration at the point of application, which enhances the shear resistance.5. ConclusionThe experimental investigation on the shear strength of concrete beams under different loading conditions revealed the following:- The shear strength of concrete beams increased with an increase in beam width and reinforcement ratio.- The loading pattern significantly influenced the shear strength, with a concentrated load at the midspan providing higher shear strength compared to a uniformly distributed load.These findings provide valuable insights for engineers in the design and construction of concrete beams, ensuring their structural integrity and safety.6. Recommendations for Future Studies- Further studies should be conducted to investigate the influence of other parameters such as concrete mix design, aggregate size, and temperature on the shear strength of concrete beams.- Numerical simulations can be employed to validate the experimental results and provide a better understanding of the shear behavior of concrete beams under different loading conditions.- The effects of different types of reinforcement (e.g., deformed steel, high-performance steel) on the shear strength of concrete beams should be explored in future studies.。
实验报告模板英文
Title:[Experiment Title]Student Name:[Your Full Name]Student ID:[Your Student ID]Course Name:[Course Name]Course Number:[Course Number]Date of Experiment:[Date of Experiment]Introduction:[Provide a brief background on the experiment. Explain the purpose, the significance of the study, and any relevant theories or concepts that will be tested.]Objective:[State the specific objectives of the experiment. What do you aim to achieve or find out?]Materials and Methods:[Describe the materials used and the methods employed in the experiment. Include details such as the following:]1. Materials:- List all the equipment, chemicals, samples, or other materials used in the experiment.- Provide descriptions of any specialized equipment or apparatus used, including specifications.2. Apparatus:- Describe the setup of the experiment, including the arrangement of equipment and the sequence of operations.3. Procedures:- Outline the step-by-step procedures followed during the experiment.- Include any safety precautions or measures taken.4. Data Collection:- Explain how data was collected during the experiment.- Include details on measurements, observations, and any other data points recorded.5. Variables:- Identify the independent and dependent variables in the experiment.- Describe how the variables were controlled or manipulated.Results:[Present the data collected during the experiment. Include tables, graphs, and figures as appropriate. Discuss the following:]1. Raw Data:- Present the raw data in tables or figures.- Include all relevant measurements, observations, and calculations.2. Analysis:- Analyze the data collected.- Discuss any patterns, trends, or relationships observed.3. Discussion of Results:- Interpret the results in the context of the experiment's objectives and background information.- Compare the results with theoretical predictions or previous studies.Conclusion:[Summarize the findings of the experiment. Address the following:]1. Summary of Results:- Restate the key findings and their significance.2. Objective Achievement:- Discuss whether the experiment achieved its objectives.3. Limitations:- Identify any limitations of the experiment, including potential sources of error or biases.4. Future Work:- Suggest areas for future research or improvements to the experiment.Discussion:[Provide a more in-depth analysis of the experiment. Include the following:]1. Comparison with Theoretical Predictions:- Compare the results with theoretical predictions or existing literature.2. Errors and Sources of Uncertainty:- Discuss any errors or sources of uncertainty in the experiment.3. Alternative Methods:- Consider alternative methods that could be used to achieve similar results.4. Practical Applications:- Discuss the potential practical applications of the experiment's findings.References:[List all the sources cited in the report, including books, journal articles, online resources, etc. Follow the appropriate citation style as required by your institution.]Appendices:[Include any additional information or data that is relevant to the experiment but not included in the main body of the report. This may include raw data tables, detailed calculations, or additional figures.]---Note: This template is a guide and should be adapted to fit the specific requirements of your experiment and the course. The length of the report will vary depending on the complexity of the experiment and the depth of analysis required.。
临床实验报告_英文
Title: Efficacy and Safety of a Novel Antidepressant in Major Depressive DisorderIntroduction:Major depressive disorder (MDD) is a common mental health condition characterized by persistent feelings of sadness, loss of interest, and decreased energy. Current treatments for MDD include selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptakeinhibitors (SNRIs), and tricyclic antidepressants (TCAs). However, some patients may not respond adequately to these treatments or experience adverse effects. This clinical trial aimed to evaluate the efficacy and safety of a novel antidepressant, known as NovelAntidepressant (NA), in the treatment of MDD.Methods:The study was a randomized, double-blind, placebo-controlled trial conducted at three academic medical centers in the United States. Participants were diagnosed with MDD according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. Inclusion criteria were age 18-65 years, a minimum Hamilton Depression Rating Scale (HDRS) score of 17, and a history of inadequate response to at least one antidepressant treatment. Exclusion criteria included pregnancy, active substance abuse, and contraindications to the study medication.A total of 120 participants were randomly assigned to one of four treatment groups: Group A (NA 50 mg/day), GroupB (NA 100 mg/day), GroupC (NA 150 mg/day), and GroupD (placebo). Participants were treated for12 weeks, with follow-up assessments at weeks 2, 4, 6, 8, 10, and 12. The primary outcome measure was the change in HDRS score from baseline to week 12. Secondary outcome measures included the Montgomery-Asberg Depression Rating Scale (MADRS), the Sheehan Disability Scale (SDS), and the Patient Global Impression of Change (PGIC).Results:A total of 113 participants completed the study. The mean age of the participants was 38.2 ± 11.7 years, and 57.5% were female. There were no significant differences in demographic or clinical characteristics between the treatment groups at baseline.At week 12, the HDRS score improved significantly in all treatment groups compared to the placebo group (p < 0.001). The mean HDRS score change from baseline to week 12 was as follows: Group A (-14.2 ± 6.1), Group B (-15.8 ± 5.9), Group C (-16.5 ± 5.7), and Group D (-6.2 ±6.5). The between-group differences in HDRS score change were not statistically significant.Similarly, the MADRS and SDS scores also improved significantly in all treatment groups compared to the placebo group (p < 0.001). The mean change in MADRS score from baseline to week 12 was as follows: Group A (-10.5 ± 4.2), Group B (-11.8 ± 3.9), Group C (-12.2 ± 3.7), and Group D (-4.8 ± 4.5). The mean change in SDS score from baseline to week 12 was as follows: Group A (-8.3 ± 3.2), Group B (-9.1 ± 2.8), Group C (-9.8 ± 2.6), and Group D (-3.4 ± 3.1).The PGIC showed a significant improvement in all treatment groups compared to the placebo group (p < 0.001). The percentage ofparticipants with a "much improved" or "very much improved" rating was as follows: Group A (75%), Group B (80%), Group C (85%), and Group D (45%).Regarding safety, the most common adverse events reported were headache, nausea, and dry mouth. These adverse events were generally mild to moderate in severity and did not lead to discontinuation of the study medication in any of the treatment groups.Conclusion:The results of this clinical trial indicate that the novel antidepressant, NA, is effective and safe in the treatment of MDD. NA demonstrated significant improvements in HDRS, MADRS, and SDS scores, as well as PGIC, compared to placebo. The adverse event profile was consistent with the known side effects of SSRIs and SNRIs. Furtherresearch is needed to confirm the long-term efficacy and safety of NA in the treatment of MDD.Keywords: Major depressive disorder, NovelAntidepressant, efficacy, safety, randomized controlled trial, HDRS, MADRS, SDS, PGIC.。
如何写实验报告英文版
Writing an Experiment ReportWriting an experiment report is a very stylized genre of writing. It should be as efficiently written as possible and should provide each item of information just where readers will expect it to be. Nothing redundant. The paper should contain 6 sections: a short Abstract, an Introduction, Methods（Process）, Results（Data）, Discussion and Conclusions. The Bibliography, Tables, Figures and typically come at the end (though the Tables and Figures can also be inserted within the text).ABSTRACT:Always include an abstract for ANY paper (in my opinion). Write it as one paragraph, about 200 words or less. This is a concise summary of the entire experiment. Include the rationale, method, results, and significance in highly abbreviated form (but using full sentences). Look at some published journal abstracts or Society Meeting abstracts to get the idea of how to write one.INTRODUCTION:Give background rationale for the experiment. Why were you motivated to do this experiment? Or more accurately, given what you actually found, why MIGHT you have wanted to do this experiment? Your report, in other words, should not be biographical or historical. Experiments are often exploratory; we often are not testing a specific hypothesis. And, in any case, readers really don't care what you THOUGHT you might find but did not. The paper should tell a story about what the data actually show. Summarize results of earlier research that are necessary to account for the conduct of the experiment (as relevant to the interesting aspects of your results) and help the reader to able to have some expectations about what the experiment will show (whether right or wrong).Pay attention to your use of verb tenses in the text. It is easy (but confusing to readers) to slip back and forth between `The subject read the words at two speaking rates' and later `We measure the duration of the vowels by ....’Avoid this.The last paragraph before the Methods should sketch in readable style the basic logic of the experimental design to come. Eg, “Thus, in the following experiment, Ss were asked to read words with both voicing values in position X at two speaking rates in order to see whether rate has an effect on the ratio of the vowel duration to consonant duration. Weexpected to find no difference in ratio due to speaking rate.'' (Or whatever.)METHODS:There are 3 logical parts to the methods: the Independent Variables(input variables, the things you controlled: place of article, word length, speaking rate, etc or whatever), the Task performed by the subjects, and the Dependent Variables. You have a task (eg, reading these phrases in a some way) for which certain values of the IV s are set (eg, +/-voice, +/- front, final stops at two speaking rates, etc.). Then you measure the DV s (eg, vowel durations, F0 contours, whatever). Finally you look for ways in which the DV s are structured by (influenced by) the IV s. This section should be tight and business-like in style.Of course, you need to tell your readers about at least the following: •characteristics of your subjects (sex, native language, age range, etc.; and the instructions you gave them),•how the recordings were made, including major equipment items, •analysis of the recordings; the measurement procedures; the software employed. Describe any special problems in measurementthat arose and your solution to them,•describe the statistics you performed, if any.RESULTS:Systematically go through the relevant aspects of your data. Present tables and graphs of the DV s. The organization of these paragraphs will probably be in terms of the IV s. For example, "The change in value of IV affects both DV1 and DV2,".)Describe the important features of the data in the text. Lead the reader through the tables and figures (eg, "As can be seen in the left side of Figure 1,..."). Devise data presentation techniques that make the real meaning of the data as clear as possible. Be sure to label graphs and figures clearly. Organization of paragraphs would normally be in terms of the independent variables.DISCUSSION:1) Organization of paragraphs (subsections) may often be in terms of independent variables (i.e. the factors varied in the experimental design).2) Compare your results to previous similar experiments. To what extent do your results resemble those found before?3) What new discoveries have you found? What is their significance to specific and more general issues in the area?CONCLUSIONS:Review and summarize very briefly what was done in this experiment and what you found in the results. State in general terms the most important discovery in the experiment. You may also want to suggest follow-up experiments.Notes on Experimental Writing Style1) Avoid first person pronouns no matter how awkward it may seem. "I asked the Ss to..." => "The Ss were asked to...".2) Paper is cheap! It is easier to spread out your text and figures and use many separate pages.3) Be as pithy as possible. Learn to use standard verbal formulas to abbreviate descriptions of methods, statistics, etc. Never be concerned that your paper is too short. It can only be too long. Say everything you have to say and no more. If you want to stretch out your paper, do it in the Discussion-- keep the Methods and Results tight, systematic and predictable.4) Make a careful outline that you update as you write. It's generally easiest to write the Methods first, then Results (starting a new page), then sketch out the Discussion (starting a new page), and finally create an easily read and descriptive title. Then write the Introduction last.5) When completed, the order of parts should be: Abstract, Text, References, Tables (on a separate pages unless very small), Figures (each on a separate page unless very small and labeled at the bottom). All tables and figures need a legend (on the page or listed on a separate page). Staple on diagonal in upper left hand corner. No fancy covers or plastic folders! Typed, of course, and EVERYTHING DOUBLE SPACED.6) Use plenty of Figures! Be creative with figures to facilitate the reader's understanding.But most of all HAVE FUN.。
动物实验报告模板英文
Title:Investigation of [Experiment Name] on [Animal Species]Authors:[Your Name(s)][Institution/Organization Affiliation][City, State, Country][Email Address(es)]Abstract:[Provide a brief summary of the purpose, methodology, results, and conclusions of the experiment. Limit to 250 words.]Keywords:[List 3-5 keywords that describe the main topics of the experiment.]1. Introduction[Provide a detailed background on the topic of the experiment. Include the rationale for the study, the specific aims of the experiment, and any relevant literature reviews.]1.1 Background[Discuss the background information related to the experiment, including any previous research that has been conducted on the topic.]1.2 Purpose[State the specific objectives of the experiment.]1.3 Hypothesis[Present the hypothesis that you are testing in the experiment.]2. Materials and Methods[Describe the materials, procedures, and methods used in the experiment in sufficient detail to allow others to replicate the study.]2.1 Animals[Provide details about the animal species used, including their age, sex, weight, and source.]2.2 Experimental Design[Describe the experimental design, including the number of animals, the groups, and the treatment protocols.]2.3 Treatments[Detail the treatments or interventions applied to the animals,including dosages, schedules, and any control conditions.]2.4 Data Collection[Explain how data was collected during the experiment, including measurements, observations, and any specific tools or techniques used.]2.5 Statistical Analysis[Describe the statistical methods used to analyze the data, includingthe software or tools employed.]3. Results[Present the results of the experiment in a clear and concise manner. Use tables, figures, and text to illustrate the findings.]3.1 [Result 1][Describe the first major result of the experiment.]3.2 [Result 2][Discuss the second major result.]3.3 [Result 3][Provide details on any additional significant findings.]4. Discussion[Interpret the results in the context of the hypothesis and existing literature. Discuss the implications of the findings, any limitations of the study, and suggestions for future research.]4.1 Implications[Discuss how the results of the experiment contribute to the understanding of the topic.]4.2 Limitations[Identify any limitations of the study, such as sample size, design, or statistical methods.]4.3 Future Research[Propose directions for future research that could build upon thefindings of this study.]5. Conclusion[Summarize the key findings of the experiment and restate the hypothesis, answering whether it was supported or refuted by the data.]6. References[List all the references cited in the report in accordance with the chosen citation style (e.g., APA, MLA, Chicago).]7. Appendices[Include any additional material that is relevant to the experiment but not essential to the main text, such as detailed methods, additional tables, or figures.]---Note:- Ensure that the report is well-organized and logically structured.- Use clear and concise language.- Include appropriate headings and subheadings for easy navigation.- Adhere to ethical guidelines for animal experimentation.- Ensure that all data is accurately represented and that statistical analyses are conducted appropriately.- Proofread the report for any grammatical or spelling errors before submission.。
各项实验报告英文
各项实验报告英文Title: Experimental Report on Various ExperimentsIntroductionIn this experimental report, we will discuss the findings and results of several different experiments conducted in the fields of physics, chemistry, and biology. Each experiment aimed to test a specific hypothesis and contribute to the overall understanding of the respective scientific discipline.Experiment 1: The Effects of Temperature on the Rate of Chemical ReactionsIn this experiment, we investigated the impact of temperature on the rate of chemical reactions. By varying the temperature of a reaction between two substances and measuring the rate of reaction at different temperatures, we were able to observe a clear correlation between temperature and reaction rate. Our findings indicated that as temperature increased, the rate of the chemical reaction also increased, supporting the well-established principle of the Arrhenius equation.Experiment 2: The Behavior of Light in Different MediumsIn this experiment, we explored the behavior of light as it traveled through different mediums. By passing a beam of light through various substances with different refractive indices, we were able to observe the phenomenon of refraction and understand how the speed of light changes in different mediums. Our results confirmed the well-known laws of refraction and provided valuable insights into the behavior of light.Experiment 3: The Effects of pH on Enzyme ActivityIn this experiment, we investigated the effects of pH on the activity of an enzyme. By subjecting the enzyme to different pH levels and measuring its activity at each pH, we were able to determine the optimal pH for the enzyme's activity. Our findings revealed that the enzyme exhibited the highest activity at a specific pH, highlighting the importance of maintaining optimal pH conditions for enzyme function.ConclusionIn conclusion, the experiments conducted in this report have provided valuable insights and contributed to the understanding of various scientific phenomena. The findings of these experiments have implications for a wide range of applications, from industrial processes to medical treatments. By continuing to conduct rigorous and systematic experiments, we can further advance our knowledge and contribute to the progress of science and technology.。
英文实验报告范例模板
Title:Investigation of [Experiment Name]Introduction:The purpose of this experiment is to [briefly describe the objective of the experiment]. This report outlines the methodology used, the results obtained, and the conclusions drawn from the experiment.Objective:To [state the specific objective of the experiment].Materials and Methods:1. Materials:- [List all the materials used in the experiment, e.g., chemicals, equipment, samples, etc.]2. Methods:- Step 1: [Description of the first step in the procedure]- Step 2: [Description of the second step in the procedure]- Step 3: [Description of the third step in the procedure]- ...- Step n: [Description of the final step in the procedure]Procedure:1. [Detailed description of the experimental procedure, including any measurements taken, observations made, or data recorded]2. [Any additional steps or modifications to the procedure]3. [Finalization of the experiment]Results:1. Data Collection:- [Present the data collected during the experiment in tables, figures, or graphs]- [Include raw data and any calculations performed]2. Analysis:- [Discuss the analysis of the data, including any statistical methods used]- [Present the results of the analysis]3. Discussion:- [Interpret the results in the context of the experiment's objective]- [Compare the results with existing literature or theories]- [Identify any unexpected results and possible explanations]Conclusion:Based on the results of this experiment, [state the main conclusion(s)]. The experiment [supported/refuted] the hypothesis that [briefly state the hypothesis]. Further research is needed to [suggest any additional studies or investigations].Discussion:1. Limitations:- [Discuss any limitations of the experiment, such as equipment limitations, sample size, or procedural issues]2. Recommendations:- [Suggest improvements to the experiment, such as using different equipment, modifying the procedure, or expanding the scope of the study]Appendices:- [Include any additional information, such as detailed data tables, code, or additional figures that support the experiment]References:- [List all the references cited in the report, following the appropriate citation style]Acknowledgments:- [Thank any individuals, institutions, or organizations that contributed to the experiment or report]Author Information:- [Include the author's name, affiliation, and contact information]---Note: This template is a general guideline and should be adapted to fit the specific requirements of the experiment and the reporting guidelines of the institution or journal.。
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The determination of nitrogen content in the ammonium salt(Formaldehyde method)
一、The experiment purpose
1、To study the application of acid-base titration
2、Master the formaldehyde method principle and the method for determination of nitrogen content in the ammonium salt
3、The use of master the volumetric flask and pipet
二、The experimental principle
Because NH4 acid is too weak to directly with NaOH standard solution titration, we usually using formaldehyde is transformed into titratable acid:
4NH4++6HCOH=(CH2)6N4H++3H++6H2O
Products, hydrogen ions and (CH2)6N4H+ can be directly for accurate titration,titration product (CH2)6N4 is weak alkaline, so using phenolphthalein as indicator.
According to the volume of the consumption of sodium hydroxide, may be calculated in proportion of nitrogen content in the ammonium salt:
w(N)=C(NaOH)·V(NaOH)·M/m×100%
三、Instruments and reagents
Equipment and materials:The alkali type buret(50ml)，Conical flask(250ml)，Volumetric flask(100ml)，pipette(20ml)，Measuring cylinder(10ml)，A beaker(100ml)，Analytical balance，Glass rod
Drugs and reagents:Sodium hydroxide standard solution(0.1083mol/L),formaldehyde(40%)，phenolphthalein(2g/L ethanol solution),Samples of ammonium sulfate(S).
四、The experimental steps
1、Accurately according to 0.60 ~ 0.85 g samples of ammonium sulfate in 50 ml beaker, add right amount water dissolves directly transferred to the 100 ml volumetric flask and constant volume, shake a backup.
2、Assimilation in sodium hydroxide standard solution to Alkali type buret after wash and embellish it.
3、Accurately move 20 ml of the solution into the clean conical flask, add 10 ml of neutral formaldehyde solution and 1 drop of phenolphthalein indicator,shake the solution and let stand for 1 minutes, to the solution with sodium hydroxide standard solution titration is not fade reddish and maintain half minutes,as it to the end.
4、Observe and record the volume of consumption of sodium hydroxide
5、Parallel determination of three times, calculate the nitrogen content in the sample and the relative average deviation dr(≤0.3%)
W(N)=(20.99%+21.01%+21.01%)/3=21.00%
d=(0.01%+0.01%+0.01%)/3=0.01%
dr=d/w(N)=0.01%/21.00%×100%=0.05%.。