Chemistry Lab Safety and Glassware

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Questions and Answers

What is the main focus of Class A glassware?

General use without precision

Resistance to heat and chemicals

Lower cost and high volume

High accuracy and tolerance (correct)

Which type of glass is characterized by excellent optical qualities and high cost?

Quartz/silica glass (correct)

Polycarbonate glass

Borosilicate glass

Soda-lime glass

Which of the following glassware is made to NIST standards?

Graduated cylinder (correct)

Beaker

Erlenmeyer flask

Soda-lime flask

What is the primary use of a volumetric flask?

Preparing standard solutions (D) Signup and view all the answers

Which characteristic differentiates Class B from Class A glassware?

Less stringent accuracy standards (A) Signup and view all the answers

Which glass type is primarily used in laboratory settings for basic tasks such as mixing?

Soda-lime glass (B) Signup and view all the answers

What is the approximate tolerance for Class B glassware?

±0.5% to ±1.0% (B) Signup and view all the answers

Which glassware is best for critical measurements in analytical chemistry?

Volumetric flask (A) Signup and view all the answers

What is the primary purpose of a fume hood in a laboratory?

To protect against inhalation of hazardous substances. (A) Signup and view all the answers

Which pipette type is calibrated to the tip?

Serological pipette (C) Signup and view all the answers

How often should the eye wash station be checked for maintenance?

Weekly (B), Annually (C) Signup and view all the answers

What should be done if chemical splashes into the eye?

Rinse for 15 minutes and remove contact lenses. (A) Signup and view all the answers

What is a critical safety instruction for using the fume hood?

Keep the sash at the recommended height. (C) Signup and view all the answers

Which piece of equipment is primarily used to measure pH levels in solutions?

pH meter (C) Signup and view all the answers

What is the main reason for performing daily and periodic inspections of the fume hood?

To ensure safety and proper function. (A) Signup and view all the answers

Which pipette type is not calibrated to the tip?

Mohr pipette (A) Signup and view all the answers

What is the primary use of an Erlenmeyer flask?

Mixing solutions and aiding in swirling (B) Signup and view all the answers

Which type of pipette is designed to deliver a fixed volume with high accuracy?

Volumetric Pipette (C) Signup and view all the answers

Which option best describes the calibration of a graduated cylinder?

Can measure accurate volumes (TD or TC) (D) Signup and view all the answers

What is a common issue associated with laboratory plasticware?

They may leach chemicals into the solutions (B) Signup and view all the answers

Which pipette type has graduations that extend to the tip?

Serological Pipette (C) Signup and view all the answers

Which statement is true regarding the features of a Florence (Boiling) flask?

It is used for heating liquids and observing reactions (A) Signup and view all the answers

Which type of plastic is known for being clear and brittle, commonly used for disposable items?

Polystyrene (C) Signup and view all the answers

What distinguishes a Mohr pipette from other pipette types?

Calibration marks do not reach the tip (C) Signup and view all the answers

What occurs if a Mohr pipette is drained beyond the last calibration mark?

It may deliver less than the stated volume. (D) Signup and view all the answers

What is the precision of estimating volume when using a graduated cylinder marked with lines at every 10 mL and the smallest division of 1 mL?

To the nearest hundredth of a milliliter. (C) Signup and view all the answers

Which of the following is considered safe practice when handling glassware in the lab?

Reporting damaged glassware to the instructor. (A) Signup and view all the answers

How should one insert glass tubing into a stopper for safety?

Lubricate the tubing and use a towel to protect hands. (D) Signup and view all the answers

What is the correct procedure for dealing with cuts in the lab?

Wash cuts, inspect for contaminants, and apply pressure. (C) Signup and view all the answers

In what situation is it acceptable to use mouth pipetting?

Under no circumstances. (A) Signup and view all the answers

What type of precision does using a graduated cylinder for volume measurement provide?

Precision to the nearest hundredth of a milliliter. (D) Signup and view all the answers

Which of the following is NOT an example of glassware mentioned for volume measurement?

Serological Pipette (A) Signup and view all the answers

What does the process of tare refer to when weighing substances?

Zeroing the scale by removing the weight of a known object. (A) Signup and view all the answers

Which calibration method involves using external standard weights?

External Calibration (C) Signup and view all the answers

How often is daily calibration recommended for balances before laboratory work?

Daily (D) Signup and view all the answers

What is the primary purpose of using micropipettes in the lab?

To transfer small quantities of liquid with high accuracy. (C) Signup and view all the answers

Which feature of a micropipette allows the user to set the desired volume?

Volume Adjustment Knob (C) Signup and view all the answers

Why is it important to avoid spills on the weighing pan of a balance?

To prevent contamination and ensure accurate measurements. (A) Signup and view all the answers

What is the maximum volume range of a P100 micropipette?

20–100 µL (B) Signup and view all the answers

Which of the following describes the tolerance in the context of balances?

The allowable degree of variation in measurements. (B) Signup and view all the answers

Study Notes

Safety Equipment

Fume hood: Protects against inhaling hazardous chemicals; should not be used for storing explosive reactions or chemicals.
Eye wash station: Used for rinsing eyes when chemicals are splashed in them.
Safety shower: Used for large chemical spills on a person.

Glassware

Soda-lime glass: The most inexpensive, low heat resistant. Commonly used for beakers, test tubes, and Erlenmeyer flasks.
Borosilicate glass: Non-reactive, high thermal resistance. Used for beakers, volumetric flasks, and graduated cylinders.
Quartz/Silica glass: Excellent optical qualities, expensive. Used for spectrophotometry cuvettes and optical lenses.
Class A glassware: Made according to NIST standards; high accuracy and tolerance, used for volumetric flasks and graduated cylinders.
Class B glassware: Less accurate than Class A; made from soda-lime glass, used for Erlenmeyer flasks and beakers.

Types of Glassware

Beaker: Useful for estimating volumes, primarily used for holding and mixing liquids.
Volumetric flask: Calibrated to contain (TC) a specific volume with high accuracy, used for preparing standard solutions.
Erlenmeyer flask: More accurate than beakers for estimating volumes, used for mixing solutions.
Florence (Boiling) flask: Used for heating liquids and observing reactions, primarily in chemistry/biology labs.
Graduated cylinder: Used for measuring urine volumes and volumes of solutes/solvents for solution preparation.
Test tubes: Used for holding small volumes of liquids.

Laboratory Plasticware

Polyethylene: Clear or opaque; commonly used for disposable test tubes and graduated cylinders.
Polypropylene: More heat-resistant, opaque; used for test tube racks.
Polystyrene: Clear, brittle; used for disposable items like petri dishes and test tubes.

Pipettes

Volumetric pipette: Class A, fixed volume delivery, used for precise measurements.
Serological pipette: Graduations extend to the tip; variable volume, calibrated to deliver, used for serial dilutions and viscous liquids.
Mohr pipette: Calibration marks do not reach the tip; variable volume, less accurate than volumetric.

Pipetting Safety

Mouth pipetting is prohibited.
Use a propipette or pipetting bulb.

Balances

Top loading balance: less precise, commonly used to quickly measure large volumes.
Analytical balance: highly precise, used to measure small amounts accurately.
Tare: Removes the weight of a known object, ensuring measurement of only substance being weighed.
Tolerance: Allowable degree of variation.
Calibration: Ensures consistent and accurate weighing results, recommended daily.
External calibration: Verifies accuracy using external standard weights.
Internal calibration: Automatic calibration using built-in weights.

Micropipettes

Can deliver fixed or variable volumes. Uses disposable tips.
Calibrated to contain the stated volume (TC and TD).
Common sizes: P2 (0.2-2 µL), P10 (1-10 µL), P20 (2-20 µL), P100 (20-100 µL), P200 (20-200 µL), P1000 (100-1000 µL).
Parts: Plunger button, tip ejector, volume adjustment knob, micrometer, volume indicator, body, shaft, tip.

Importance of Pipette Calibration

Maintains accuracy and precision.
Ensures compliance with lab accreditation and quality of testing results.
Types covered: Volumetric, serological, and Mohr pipettes.

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Description

Test your knowledge about essential safety equipment and various types of glassware used in the chemistry lab. This quiz covers the functions of safety gear as well as the characteristics of different glassware types, from soda-lime to borosilicate glass. Perfect for students preparing for lab work or just wanting to refresh their chemistry knowledge.