answer:1. Volatility and evaporation of hexane and acetone (Most important) The most crucial source of experimental error in the direct analysis of an air sample is the volatility and evaporation of hexane and acetone. Both compounds exhibit high volatility and can easily evaporate into the atmosphere. Failure to close the impinger immediately after adding hexane and acetone can cause considerable evaporation of these substances. This evaporation leads to a lower measured concentration in the air sample, rendering the final result reading lower than the actual value. To mitigate this error, it is essential to close the impinger as soon as hexane and acetone are added, thus minimizing the evaporation losses and ensuring accurate and reliable analytical results. 2. Inaccurate timing and pump calibration The second most important source of experimental error is inaccurate timing and pump calibration when collecting the air sample in the tedlar bag. If the timing is not precise, the tedlar bag may be filled beyond its capacity or not filled enough, which would alter the concentrations determined by the IR analysis. An overfilled tedlar bag may lead to an overestimation of the concentration of hexane and acetone, while an underfilled bag may result in an underestimation. To address this issue, it is vital to ensure that the timing approach used in conjunction with the calibrated pump is exact and precise. Properly monitoring the sample collection process and maintaining the calibrated pump will help to achieve accurate sample concentrations as determined by the IR analysis. In summary, the two main sources of experimental error are the volatility and evaporation of hexane and acetone and the inaccurate timing and pump calibration in sample collection. These errors can lead to either an overestimation or underestimation of the actual concentration values, affecting the overall reliability and accuracy of the analysis. Proper handling of the impinger and ensuring precise timing and pump calibration can help to minimize these errors and produce reliable analytical results.

answer:In this experiment, the sample should typically not be passed through the air sampling pump for several reasons: 1. Contamination and chemical residue: Chemical residues from the samples passing through the sampling pump may be left behind, leading to potential contamination of the pump. Air sampling pumps are designed to be clean and contaminant-free, but direct introduction of samples can deposit airborne pollutants and contaminants into the pump, degrading its performance and compromising its cleanliness. 2. Cross-contamination: If the sampling pump has been utilized for multiple sample collections, the residual contaminants from previous samples may mix with the current sample, leading to cross-contamination. This can result in skewed and unreliable analytical results while also limiting the pump's effective use for future sampling efforts. 3. Damage to the pump: The continuous introduction of samples into the pump can cause harm to the pump's internal components, reducing its operational efficiency and potentially leading to equipment failure. Chemical residues and pollutants from the samples may erode, corrode, or otherwise negatively impact the pump's functioning, shortening its lifespan and necessitating costly repairs or replacements. 4. Impact on analytical results: As the sampling pump becomes contaminated, the pollutants and chemical residues may interfere or interact with subsequent samples, ultimately compromising the accuracy and representativeness of the analysis. This can lead to unreliable results and undermine the validity of the data collected from the air samples. In conclusion, allowing the sample to pass directly through the air sampling pump can cause contamination, damage to the pump, cross-contamination between samples, and negatively affect the overall analytical results. These factors emphasize the importance of avoiding direct sample introduction into the air sampling pump to maintain its integrity, performance, and reliability for accurate air sample analysis.

answer:Passing the sample directly through the air sampling pump should be avoided for the following reasons: 1. Contamination: Chemical residues from samples can contaminate the pump, which is designed to be clean and contaminant-free, degrading its performance and cleanliness. 2. Cross-contamination: Residual contaminants from previous samples in the pump can mix with the current sample, compromising its accuracy and reliability. 3. Pump damage: Chemical residues and pollutants from samples can harm the pump's internal components, reducing efficiency, causing equipment failure, and increasing repair or replacement costs. 4. Analytical impact: Contaminants in the pump can interfere with subsequent samples, leading to unreliable results and undermining the data's validity. In summary, direct sample introduction into the air sampling pump should be avoided to maintain its integrity, performance, and reliability for accurate air sample analysis.

answer:Required Personal Protective Equipment: Protective lab coat, safety glasses, closed-toe shoes Protective lab coat, safety glasses, closed-toe shoes Primary Exposure Route: Inhalation, absorption Inhalation, absorption Exposure Symptoms & First Aid Measures: Headache, increased salivation, nausea, vomiting, dizziness, unconsciousness, coma First aid: Following inhalation: Seek fresh air or proceed to the emergency room. If skin contact occurs: Remove contaminated clothing immediately. Thoroughly rinse skin with water, or take a shower. Feeling drowsy, irritation, sleepiness, nausea, fatigue, central nervous system (CNS) abnormalities, paralytic symptoms First aid: In case of inhalation: Breathe fresh air. Upon skin contact: Immediately remove contaminated clothing, and thoroughly rinse skin with plenty of water. Waste Disposal Methods: Take liquid acetone to an authorized hazardous waste treatment, storage, disposal, or recycling facility for proper disposal. Allow the container to completely volatilize any remaining liquid within the functioning hood's airflow. Measures for Cleaning Spills: Cover drainage openings. Bind, collect, and pump spilled substances. Cover drainage openings. Bind, collect, and pump spilled substances.