Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chemistry Lab (Ch 2: Basic Laboratory Techniques (Lab Tools (General types…
Chemistry Lab
Ch 2: Basic Laboratory Techniques
Measuring system
Every measurement is an approximation
Metric system
Based on the fundamental properties of H2O
Physical quantity
Length
Meter (39.37 in)
Volume
Cubic meter
Mass
Kilo
Energy
Joule
Temperature
Kelvin
Lab Tools
Laboratory balance
Used to:
Obtain the mass of various objects
2 Types:
Analytical balance
Top loader
General types of glassware
Cylinders
Graduated cylinders
Critical for the cylinder to have a uniform diameter along its entire height
A tall cylinder w/ a small diameter will be more accurate than that of a short one with a large diameter
Volumes are measured by measuring the height of a column of liquid
Characteristics:
Tall, cylindrical vessels w/ graduations scribed along the side of it
Measures volume
Small cylinders are more accurate b/c they have smaller lines
Beakers
CH: Straight parallel sides
Common size - 250 ml
Use - To hold things
Beaker tongs
Use - To hold the beaker
Flasks
CH - Looks like a cone where the sides slope in
Name - Erlenmeyer flask
Use - Hold things - Chemical reactions to prevent splashes
Test tubes
Use - To do small chemical reactions
To hold it - Test tube holder
Crucible
Made of porcelain
Use - To heat things
Crucible tongs
Thermometers
Based on the principle that liquid expands when heated
Most common ones use mercury & colored alcohol
To calibrate a thermometer, one defines 2 ref points,
Freezing point 0C and boiling point of H2O 100C
The boiling point also depends on atmospheric pressure
Temperature formula - b.p. correction = (760 mm Hg - atmospheric atmosphere) x 0.037 C/mm = 100 C - b.p. correction
Pipets
