Lab Safety
What is the first thing you should do if something breaks in the lab?
Tell the teacher!
Which instrument is best for measuring 45.0 mL of water accurately?
10 mL graduated cylinder
50 mL beaker
100 mL graduated cylinder
100 mL graduated cylinder
What tool do you use to mass 100.0 g of a substance?
Electronic balance
Name the two major types of observations discussed in class.
Qualitative and Quantitative.
Define accuracy.
Closeness to true value. Correctness.
True/False: It is okay to remove goggles once you’ve finished your experiment, even if others are still working.
False!
When measuring liquid in a graduated cylinder we also measure from the bottom of the downward curve called the...
Meniscus
Which piece of equipment is used to transfer salt from a beaker to a weigh boat?
Scoopula
Which is quantitative: “The temperature increased by 25°C” or “The solution turned pink”?
The temperature increased by 25°C
Define precision
Consistency of measurements
Name three safety precautions we must take when using Bunsen Burners.
Answers will vary.
How many centimeters in a meter?
100 cm
Identify the following piece of lab equipment.
Erlenmeyer Flask
Lizzie boiled off liquid and measured 16.0 g of pink crystals. Quantitative or qualitative?
Quantitative
You measure 92.00, 91.00, and 90.75 cm for a door that is actually 91.50 cm wide. Accurate, precise, both, or neither?
Both
Identify two lab safety violations you might see in a picture of a lab scene.
Answers vary.
What is the resolution of the tool?
0.1 cm
Which part of the Bunsen burner controls flame height?
Give one qualitative and one quantitative observation of this room.
Answers will vary.
Why can a measurement be precise but not accurate?
The measurements are wrong but they are consistent.
Why is it unsafe to wear contact lenses in the lab?
They can trap chemicals against the eye
What is the resolution of the tool?
How much liquid is in the graduated cylinder?
1 mL
What does adjusting the air adjustment on a Bunsen Burner do?
Changes the color/temperature of the flame.
During a lab, you record that a reaction produces a strong odor, a temperature increase of 12.5°C, and a color change from clear to green.
Identify which observations are qualitative and which are quantitative.
Qualitative: strong odor, color change
Quantitative: temperature increase of 12.5°C
Which tool would provide more precise measurement: a 50 mL beaker or a 50 mL graduated cylinder? Why?
Graduated cylinder. They have a smaller resolution (lines are closer together).