39 Questions
What is the primary purpose of a Bunsen burner in a chemistry laboratory?
To create a small flame for heating and igniting reactions
Which of the following laboratory equipment is used to measure volume most precisely?
Pipette
What is the primary purpose of a fume hood in a chemistry laboratory?
To minimize exposure to harmful vapors or fumes
What is the purpose of a safety shower in a chemistry laboratory?
To deliver a continuous stream of water to someone splashed with toxic or corrosive chemicals
Which of the following laboratory equipment is used to perform titrations?
Burette
What is the purpose of a calorimetry experiment in a chemistry lab?
To determine the amount of heat energy released or absorbed during a chemical reaction
Which statement about Erlenmeyer flasks is correct?
They have a wider base and narrow neck, making them suitable for mixing and swirling solutions.
What is the primary purpose of boiling flasks?
To swirl and heat liquids, often requiring a clamp to keep them in position.
Which statement about volumetric flasks is incorrect?
They are commonly used for preparing or diluting chemical solutions to an approximate volume.
Which feature distinguishes a volumetric flask from an Erlenmeyer flask?
A volumetric flask has a long, narrow neck, while an Erlenmeyer flask has a shorter, wider neck.
What is the primary function of a dropper?
To transfer small amounts of liquid from one container to another.
Which statement about boiling flasks is true?
They have a round bottom and often require a clamp or corkscrew ring to keep them in position.
Which statement is correct about centrifugation?
It separates components based on their density differences.
What is the number of significant digits in the value 3020?
3
When multiplying or dividing, the final answer is expressed to the ___ degree of significant numbers based on the numbers being multiplied or divided.
lowest
What is the purpose of taring a balance before weighing a sample?
To account for the mass of the sample holder.
In a titration, what is the relationship between the equivalence point and the endpoint?
The equivalence point is the point at which the titrant has completely reacted with the reagent, while the endpoint is an observable property change.
In the addition problem $34 + 240 + 456.4$, the final answer would be rounded to the ___ place.
tens
Which piece of glassware would be most appropriate to use for accurately measuring $5.0$ mL of a liquid?
A burette
Which of the following is an example of a systematic error?
Forgetting to tare the electronic balance before taking measurements
Systematic errors are errors that are ___ in one direction, either above or below the true value, and to the ___ extent each time.
consistent, same
What is the primary difference between 'volumetric' and 'graduated' glassware?
Volumetric glassware has a single marking indicating a specific volume, while graduated glassware has multiple markings.
If the burette in the given example has a total volume of 50 mL and the reading is 5.6 mL, what is the volume of liquid contained within the burette?
44.4 mL
What is the primary difference between systematic and random errors?
Systematic errors are consistent in direction and magnitude, while random errors are unpredictable.
When adding or subtracting values with different levels of accuracy, the final answer is expressed to the accuracy of the ___ accurate digit.
least
Which of the following is NOT a characteristic of systematic errors?
Unpredictable in magnitude
In the context of significant digits, which of the following statements is true?
The number of significant digits is determined by the placement of zeros in the value.
Which of the following is an example of a random error?
Fluctuations in room temperature during an experiment
Which of the following statements is true regarding significant digits?
Zeros between two non-zero digits are significant digits
In the experiment where a student obtained concentrations of 26.5, 27.0, 26.8, and 26.7 M for a solution with a known concentration of 30.0 M, the results are described as:
Precise but inaccurate
How many significant digits are in the value 0.00450?
4
Which of the following statements about safety in a lab is correct?
Broken glass should be cleaned up immediately with caution
What is the correct way to add water to a concentrated acid?
Add the acid to water
Which of the following personal protective equipment (PPE) should be worn in a lab?
Lab coat, safety goggles, and gloves
What is the purpose of a dropper, also known as a Pasteur pipette?
To deliver a liquid in a drop-wise fashion
What is the primary function of a burette in a titration experiment?
To deliver a precise volume of a titrant to a solution
What is the purpose of the stopcock on a burette?
To control the amount of liquid released by the burette
How is the volume of a titrant delivered from a burette determined?
By subtracting the final volume in the burette from the initial volume
What is the purpose of the tare button on a digital balance?
To reset the reading to zero, excluding the weight of any object on the scale
Study Notes
Laboratory Equipment
- Beaker: a wide-mouthed vessel used to hold, heat, stir, or mix solutions; not accurate for measuring volume
- Graduated cylinder: a thinner cylindrical tube used to measure a variety of volumes; more accurate than beakers, but not as accurate as volumetric flasks or burettes
- Erlenmeyer flask: a conical flask with a narrowed neck used for mixing, heating, and stirring solutions; not accurate for measuring volume
- Volumetric flask: a round flask with a long, thin neck used to create dilute solutions; very accurate for measuring volume
- Boiling flask: a round-bottomed flask with a longer neck used to swirl and heat solutions; not used for measuring volume
- Pipette: the most precise way to measure volume, used to transfer a specific amount of volume
- Burette: a long, graduated tube used in titrations to deliver highly accurate volumes of liquid
- Test tube: small, glass tubes with rounded bottoms used for mixing, comparing, and storing liquids; not used for measuring volume
- Dropper: small glass tubes with a rubber bulb at the end used to dispense small amounts of liquid drop-wise
- Bunsen burner: a metallic apparatus that produces an open flame for heating purposes
- pH meter: a device used to accurately measure the pH of a solution; must be calibrated before each use
- Digital balance: a device used to accurately measure the mass of a solid sample
Safety Protocols
- Safety shower: delivers a continuous stream of water to anyone splashed with toxic or corrosive chemicals
- Eye wash station: treats any splashes of chemicals in or near the eyes
- Fume hood: provides proper ventilation in an enclosed space to minimize exposure to harmful vapors or fumes
Laboratory Techniques
- Titration: a method used to deliver drop-by-drop volumes of a titrant to another solution to measure the volume of the titrant needed to react completely with the other reagent
- Centrifugation: a process that separates different parts of a mixture using a centrifuge
- Filtration: a process used to separate a solid pellet from a liquid supernatant
- Decantation: a process used to separate a liquid supernatant from a solid pellet
Error Analysis
- Systematic error: consistently skewed in one direction, either above or below the true value
- Random error: unpredictable and varies in both directions
- Percent error: the ratio of the absolute error to the true value, multiplied by 100
Significant Digits
- All non-zero numbers are significant
- Zeroes between two non-zero numbers are significant
- Trailing zeroes after the decimal point are significant
- Other zeroes are not significant
Learn about the differences between beakers and Erlenmeyer flasks, their uses, and why Erlenmeyer flasks are preferred for mixing and swirling solutions. Understand the advantages and disadvantages of each type of flask.
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