Lab Safety
What is the first step you should take if a chemical spills on your skin during a lab experiment?
Immediately rinse the affected area with plenty of water for at least 15 minutes and notify the teacher.
Name one common physical hazard found in the laboratory.
slips, trips, and falls, hazards from sharps like broken glass, electrical equipment, compressed gases, extreme temperatures (both hot and cold), radiation, lasers, pressurized equipment, and mechanical hazards from moving machinery.
What is the primary use of a graduated cylinder?
A graduated cylinder is used to measure the volume of liquids accurately.
What unit is commonly used to measure volume in the lab?
The liter (L) or milliliter (mL) is commonly used to measure volume.
How many significant figures are in the number 0.00520?
The number 0.00520 has 3 significant figures.
Why is it important to wear safety goggles in the laboratory?
Safety goggles protect your eyes from chemical splashes, flying debris, and harmful vapors.
What type of hazard does a corrosive chemical represent?
A corrosive chemical represents a chemical hazard that can damage skin or materials.
How do you properly clean a glass beaker after an experiment?
Rinse the beaker with water, then with appropriate cleaning solution if needed, and finally rinse with distilled water.
How do you read the meniscus in a liquid measurement?
Read the bottom of the meniscus at eye level to get an accurate liquid measurement.
Round the number 23.6789 to three significant figures.
Rounded to three significant figures: 23.7.
Describe the proper way to smell a chemical in the lab safely.
Waft the chemical vapors toward your nose with your hand instead of directly inhaling.
How can electrical hazards occur in a laboratory setting?
Electrical hazards can occur from exposed wires, overloaded circuits, or improper use of electrical equipment.
What is the difference between a pipette and a burette?
A pipette is used to transfer a precise volume of liquid, while a burette is used to deliver variable volumes during titration.
Convert 250 milliliters to liters.
250 milliliters = 0.250 liters.
When multiplying 4.56 (three significant figures) by 1.4 (two significant figures), how many significant figures should the answer have?
The answer should have 2 significant figures (the smallest number of sig figs in the factors)
What should you do if you notice a broken piece of glassware in your lab area?
Notify the teacher and carefully dispose of the broken glass in the designated sharps container.
What precautions should be taken when working with flammable substances?
Keep flammable substances away from open flames and heat sources; use in a well-ventilated area.
What equipment is used for measuring how much light a substance absorbs at different wavelengths.
Spectrophotometer
Why is it important to use proper units when recording data?
Proper units ensure consistency, accuracy, and clear communication of data.
Explain the difference between exact numbers and measured numbers in terms of significant figures.
Exact numbers have infinite significant figures (counted or defined values), while measured numbers have limited significant figures based on measurement precision.
Explain why eating or drinking is prohibited in the laboratory.
Eating or drinking can lead to accidental ingestion of hazardous chemicals and contamination in the lab.
Describe the potential health effects of inhaling toxic fumes in a lab.
Inhaling toxic fumes can cause respiratory problems, dizziness, or long-term health damage depending on the chemical.
What is the term for the lines in a measuring tool?
Graduation Lines or Graduated Lines
Calculate the density of an object with a mass of 150 grams and a volume of 50 cubic centimeters
Density = mass ÷ volume = 150 g/50 cm3=
3 g/cm3
Perform the following calculation and express the answer with correct significant figures:
(12.11+0.023)×3.2
First, add: 12.11+0.023=12.133(rounded to 2 decimal places)
Then multiply: 12.13×3.2=38.8 (2 significant figures, based on 3.2)
Final answer: 38.8