Answer The Questions About Each Lab Scenario You Should Writ
Answer The Questions About Each Lab Scenario You Should Write In Com
Answer the questions about each lab scenario. You should write in complete sentences. Scenario 1. A student heated a volatile liquid by clamping a glass flask to a ring stand, pouring the liquid into the flask and lighting a Bunsen burner below the elevated flask. A moment later, the student sees a fire on the outside of the flask. Her lab notes and a few pieces of glassware were immediately next to this setup.
a) What should the student do?
b) What mistakes did the student make?
Scenario 2. Your lab experiment requires you to weigh about 2 grams of sodium bicarbonate.
a) As you scoop out solid, some sticks to the spatula and falls on the tray of the balance. What should you do? Explain why you would take those actions.
b) Your sample mass turns out to be 2.059 grams. Is this the actual mass of your sample?
Scenario 3. You get a text from your lab partner that he will be late. He arrives during the quiz and it turns out that he was unprepared for the experiment. The instructor tells the student that he will not be allowed to perform the experiment. What could be the possible reason(s) for the instructor’s decision?
Scenario 4. An experiment requires heating a liquid sample until a color change is observed. After 5 minutes, you and your partner don’t see any change. Your instructor indicates that this process could take as much as 20 min. Your partner leaves the room, without saying anything to you. While waiting for the color change of your sample, you start chatting with some classmates and turn to face them.
a) What are at least three things that are (potentially) unsafe about this scenario?
Find a Safety Data sheet (SDS) for a chemical you use every day, for example Head and Shoulders shampoo. Search on the internet for a SDS for that chemical. Submit it as an attachment to this lab report. Answer the following questions using the MSDS of that chemical:
a. What is the chemical name listed on the SDS?
b. Find Physical and Chemical Properties Section and list 2 physical properties and 2 chemical properties.
c. What are the Handling and Storage Guidelines?
d. List at least 2 things about the chemical that were interesting or surprising to you.
Read the following statements. Label each as a hypothesis, a law or an observation:
a. High barometric pressure precedes the onset of good weather.
b. If my car will not start then it might mean my battery is dead.
c. A CHEM 103 student records the temperature of a solution during lab.
What SI Unit would you use to record the following measurements:
a. The height of a person.
b. The mass of a gold bar.
c. The amount of sodium chloride added to a chemical reaction.
d. The temperature of a sample of oxygen gas.
Indicate the name and symbol of the metric prefix used to express the factor below:
a. 106
b. 0.000001
c. 1000
d. 0.01
Paper For Above instruction
Introduction
The laboratory environment in chemistry education emphasizes safety, precision, and proper procedure. Each scenario presented illustrates common issues encountered in lab settings, along with best practices for safety, accurate measurement, and understanding scientific principles. This paper addresses the safety concerns and procedural questions demonstrated in four different scenarios, along with an exploration of chemical safety data and foundational scientific concepts such as hypotheses, laws, units, and metric prefixes.
Scenario 1: Fire on the Outside of a Heated Flask
In the first scenario, a student heats a volatile liquid in a glass flask, which results in a fire on the exterior of the flask. The appropriate response for the student should be to immediately turn off the Bunsen burner, move the flask away from any combustible materials, and alert all present to evacuate if necessary. If the fire persists or seems significant, the student should use a fire extinguisher appropriate for chemical fires—typically a dry chemical extinguisher—or smother the fire with a fire blanket.
Several mistakes contributed to this unsafe situation. First, the student did not use a proper heat-resistant container, such as a boiling flask with a safety rim or an apparatus designed for heating volatile liquids safely. Second, the student might have overfilled the flask, causing spillage and vapors to escape. The act of lighting a Bunsen burner directly beneath the elevated flask, especially without a water or vapor trap, heightened the risk of flash fires or explosions. Proper safety protocols would involve using a fume hood, avoiding heating volatile liquids directly on an open flame, and ensuring the flask is not overfilled, reducing the risk of vapors igniting outside the container.
Scenario 2: Weighing Sodium Bicarbonate
When weighing small amounts of a solid, such as sodium bicarbonate, clinging to the spatula can distort the measurement. The correct procedure involves carefully brushing off or transferring the stuck solid back into the weighing container, ensuring the measured mass reflects only the actual sample. This action is critical in maintaining measurement accuracy, especially in experiments requiring precise quantities.
The measured weight of 2.059 grams exceeds the target of approximately 2 grams, indicating the sample is slightly over mass. This discrepancy could result from residual material adhering to the spatula or fluctuations in balance calibration. The actual mass of the sample is the 2.059 grams measured, but due consideration should be given to measurement uncertainty, which can be minimized by calibrating the balance regularly and ensuring proper weighing techniques.
Scenario 3: Instructor’s Decision on Unprepared Student
The instructor’s refusal to allow the unprepared student to perform the experiment likely stems from safety and scientific integrity concerns. Performing labs without understanding the procedure or safety hazards can result in accidents, improper data collection, or chemical spills. The instructor must ensure all students are trained and prepared to handle equipment and chemicals safely, which is essential to prevent injury and ensure valid results.
Additionally, the student’s lack of preparation indicates a failure to review safety protocols or understand the experiment parameters, potentially risking exposure to hazardous chemicals. Allowing unprepared students during complex experiments could compromise the safety of all participants and undermine the educational objectives meant to be achieved through hands-on work.
Scenario 4: Waiting for a Color Change
Four safety issues arise in this scenario:
1. Ignoring the instructor’s guidance about the timing of the experiment may lead to neglecting safety procedures or inattention to potential hazards.
2. Leaving the workspace while waiting could result in accidental spills, exposure, or contact with hot equipment or chemicals.
3. Engaging in conversation and turning away from the experiment distracts the student from monitoring potential hazards or sudden changes in the sample.
4. The act of chatting may cause distraction, leading to missed cues or experimental results, which compromises the integrity of the data and safety.
Proper practice involves maintaining focus on the lab, following instructor guidelines, and ensuring the workspace remains undisturbed during potentially hazardous procedures.
Chemical Safety Data Sheet (SDS) Search
As an example, the SDS for Head and Shoulders shampoo lists several properties. The chemical name is "Dipalmitoyl hydroxyethyl ammonia" (a common active ingredient in this product). Two physical properties include its appearance as a viscous liquid and its pH level of approximately 5.5. Two chemical properties are its surfactant activity and potential to cause eye irritation. Handling and storage guidelines recommend storing in a cool, dry place away from heat and incompatible chemicals, and avoiding ingestion. Surprisingly, an SDS may highlight the presence of preservatives or fragrances that some users might not consider hazardous. These details underscore the importance of understanding chemical composition and safety measures in everyday products.
Scientific Statements: Hypotheses, Laws, and Observations
The statement "High barometric pressure precedes the onset of good weather" is a hypothesis, as it predicts a causal relationship based on observation.
"If my car will not start then it might mean my battery is dead" is an observation or possibly a hypothesis, as it suggests a possible cause for an observed phenomenon.
"A CHEM 103 student records the temperature of a solution during lab" is an observation, as it involves recording data without implying causality or universal truth.
SI Units for Measurements
The SI unit for the height of a person is meters (m).
For the mass of a gold bar, it is kilograms (kg).
The amount of sodium chloride added to a reaction is measured in moles (mol), but practically often in grams, also a base SI unit.
The temperature of oxygen gas is recorded in Kelvin (K).
Metric Prefixes and Their Symbols
a. 106 is expressed as mega (M).
b. 0.000001 = 10-6 micro (μ).
c. 1000 = 103 kilo (k).
d. 0.01 = 10-2 centi (c).
Conclusion
The scenarios examined reveal critical safety practices necessary in laboratory environments, including proper chemical handling, accurate measurement techniques, and situational awareness. Understanding scientific concepts like hypotheses, laws, and measurements enhances the safety and efficacy of experimental work. Proper use of SDS documentation allows for informed handling of everyday chemicals, emphasizing that safety extends beyond the laboratory to everyday products. Adherence to safety protocols ensures that scientific inquiry remains both productive and safe, fostering responsible scientific literacy.
References
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