[화학과 수석의 A+ 레포트] 뷰렛의 검정 (분석화학실험)

문서 내 토픽

1. Calibration of Volumetric Glassware

이 실험의 목적은 buret을 교정하고 그를 바탕으로 교정 곡선을 작성해, 앞으로의 분석화학실습에서 buret을 사용하는 실험을 할 때 해당 buret의 교정 곡선을 참고자료로 하여 실험의 정확도를 높이는 데에 있다. 교정 곡선의 x축은 buret으로 측정한 물의 부피, y축은 실제 물의 부피에서 buret으로 측정한 물의 부피를 뺀 오차값으로 세웠다. 그 결과, 5mL에서는 +0.02mL, 10mL에서도 +0.02mL, 15mL에서는 +0.01mL, 20mL에서는 -0.01mL, 25mL에서는 +0.01mL의 오차가 나타났다.
2. Calibration Curve

교정 곡선은 알려진 양의 분석물질에 대한 분석방법의 감응을 보여주는 곡선이다. 실제 부피를 구하는 과정에서 온도에 따른 물의 밀도, buoyancy 등을 고려해 계산된 correction factor를 사용했다. buoyancy를 고려하는 이유는 분석 저울로 물의 질량을 측정할 때 공기에 의한 buoyancy의 영향을 받아서, 실제 물의 질량보다 물이 차지하는 부피에 해당하는 공기의 질량만큼 더 가볍게 측정되기 때문이다.
3. Buoyancy Equation

실제 물의 질량을 구하려면 buoyancy를 고려한 buoyancy equation을 계산해야 한다. m = {m' (1- {d_a} / {d_w})} / (1- {d_a} / {d}), 여기서 m은 물의 실제 질량, m'은 저울로부터 읽은 질량, d_a는 공기의 밀도, d_w는 교정추의 밀도, d는 물의 밀도다.
4. Experimental Procedure

buret을 증류수로 채우고 meniscus가 0.00 mL에 오도록 조절한 후, 100mL Erlenmeyer flask와 마개의 무게를 우선 함께 측정했다. 그리고 buret에서 flask로 약 5mL의 물을 천천히 따라낸 후, buret의 눈금을 읽고 마개로 막은 flask의 무게를 쟀다. buret에서 flask로 총 25mL를 따라낼 때까지 5mL의 간격으로 앞의 과정을 반복했다.
5. Data and Results

1st measurement와 2nd measurement의 data를 바탕으로 오차값을 계산했다. 각 부피 지점당 평균 오차값을 그린 교정 곡선에 따르면, buret 눈금 5mL 지점에서는 +0.02mL, 10mL 지점에서도 +0.02mL, 15mL 지점에서는 +0.01mL, 20mL 지점에서는 -0.01mL, 25mL 지점에서는 +0.01mL로, 해당 buret으로 측정한 부피는 실제 부피와 -0.01mL ~ 0.02mL 정도의 차이가 존재했다.

Easy AI와 토픽 톺아보기

1. Calibration of Volumetric Glassware

Calibration of volumetric glassware is a critical step in analytical chemistry to ensure accurate and precise measurements. It involves determining the true volume of a piece of glassware, such as a pipette or volumetric flask, by comparing its measured volume to a known standard. This process is essential for obtaining reliable results in quantitative analysis, as even small errors in volume measurements can significantly impact the final calculations and conclusions. Proper calibration techniques, including the use of reference materials and appropriate statistical analysis, are necessary to minimize systematic and random errors. Additionally, regular recalibration is recommended to account for potential changes in the glassware over time due to factors like temperature, pressure, and wear. Overall, the calibration of volumetric glassware is a fundamental practice that underpins the accuracy and reliability of analytical data in various fields, including chemistry, biology, and environmental science.
2. Calibration Curve

A calibration curve is a fundamental tool in analytical chemistry, used to establish a relationship between a measured instrumental response and the concentration of an analyte in a sample. The process of creating a calibration curve involves measuring the instrument's response (e.g., absorbance, fluorescence, or electrical signal) for a series of standard solutions with known analyte concentrations. By plotting the instrument response against the known concentrations, a calibration curve can be generated, typically using linear regression. This curve then serves as a reference to determine the unknown concentration of the analyte in a sample by interpolating the measured instrument response. Calibration curves are essential for quantitative analysis, as they allow for the accurate determination of analyte concentrations, even at low levels, by accounting for factors such as instrument sensitivity, matrix effects, and potential interferences. Proper construction and validation of calibration curves are crucial to ensure the reliability and reproducibility of analytical results across various applications, including environmental monitoring, pharmaceutical analysis, and clinical diagnostics.
3. Buoyancy Equation

The buoyancy equation, also known as Archimedes' principle, is a fundamental concept in physics that describes the upward force exerted on an object immersed in a fluid. This equation states that the buoyant force acting on an object is equal to the weight of the fluid displaced by the object. Understanding and applying the buoyancy equation is crucial in various fields, such as fluid mechanics, oceanography, and engineering. In analytical chemistry, the buoyancy equation is particularly relevant in the calibration of volumetric glassware, where the true volume of the glassware must be determined by accounting for the buoyant force acting on the object when it is immersed in a fluid, typically water. Accurate application of the buoyancy equation, along with considerations of factors like temperature and fluid density, ensures that the true volume of the glassware is correctly measured, leading to more reliable analytical results. Additionally, the buoyancy equation is essential in the determination of the density of substances, which is a critical parameter in many chemical and physical analyses. Overall, the buoyancy equation is a fundamental principle that underpins a wide range of applications in science and engineering.
4. Experimental Procedure

The experimental procedure is a crucial component of any scientific investigation, as it outlines the step-by-step instructions for conducting the study and collecting data. In the context of analytical chemistry, a well-designed experimental procedure is essential for ensuring the reliability and reproducibility of the results. The experimental procedure should clearly describe the materials, equipment, and methods used, as well as any relevant experimental conditions, such as temperature, pressure, and time. It should also include detailed instructions for sample preparation, calibration of instruments, and data collection. Careful attention to the experimental procedure helps to minimize systematic and random errors, and ensures that the results can be verified and replicated by other researchers. Additionally, a thorough experimental procedure allows for the identification and control of potential sources of error, enabling the researcher to assess the validity and limitations of the data. Overall, the experimental procedure is a critical element of the scientific method, as it provides a transparent and replicable framework for conducting analytical investigations and generating reliable, high-quality data.
5. Data and Results

The data and results section of an analytical chemistry study is the culmination of the experimental work and is essential for communicating the findings to the scientific community. This section should present the collected data in a clear and organized manner, using appropriate tables, graphs, and statistical analyses to summarize the key findings. The data should be presented in a way that allows the reader to understand the trends, patterns, and relationships observed in the experiment. Additionally, the results section should include a discussion of the significance and implications of the findings, as well as any limitations or sources of error that may have influenced the data. Careful and transparent reporting of the data and results is crucial for the scientific process, as it allows other researchers to evaluate the validity and reliability of the study, and to build upon the existing knowledge in the field. Furthermore, the data and results section serves as the foundation for the interpretation and discussion of the findings, and ultimately, the conclusions drawn from the study. Overall, the data and results section is a critical component of any analytical chemistry investigation, as it provides the evidence and justification for the conclusions and recommendations presented in the study.