CHEMISTRY
OCTOBER 2, 2014
LAB 2 – Quantitative vs. Qualitative
PRE-LAB
• Take 2 minutes to read the PreLab on page 1 of the packet. This
is silent and solo activity.
OBJECTIVE
• SWBAT
– Learn to perform qualitative observations
– Learn to perform quantitative observations
AGENDA
–Pre-Lab
–Perform the Lab
–Complete the Lab Questions
IMPORTANT DATES
• Quiz 03 – Friday
– First 15 minutes
• Test 01 – Next Friday
TRIPLE BEAM BALANCE
TRIPLE BEAM BALANCE
• The triple beam balance is used to measure
mass
• Calibrate before measurement
HOW TO USE THE TBB
– place the object to be measured on the pan
– Move the 100 gram slider along the beam to the
right until the indicator drops below the fixed
mark. The notched position immediately to the
left of this point indicates the number of hundreds
of grams.
– Now move the 10 gram slider along the beam to
the right until the indicator drops below the fixed
mark. The notched position immediately to the
left of this point indicates the number of tens of
grams.
HOW TO USE THE TBB (cont’)
– The beam in front is not notched; the slider can
move anywhere along the beam. The boldface
numbers on this beam are grams and the tick
marks between the boldface numbers indicate
tenths of grams.
– To find the mass of the object on the pan, simple
add the numbers from the three beams.
QUESTIONS
• Answer questions 4-6 related to the TBB
GRADUATED CYLINDER
GRADUATED CYLINDER
• The graduated cylinder is used to measure
volume
• Graduated cylinders come in various sizes.
– Record yours
– What is the maximum capacity of your graduated
cylinder?
– What is the smallest division of your cylinder?
– How many decimal places should be included in
reporting a measured volume?
GRADUATED CYLINDER READING
MENISCUS
• Read the graduated cylinder by reading the
meniscus (the lowest portion of the convex
dip of the liquid)
– Meniscus form because of adhesion force is
stronger than cohesion force
USING THE INSTRUMENTS
QUALITATIVE OBSERVATIONS
• Record your observations into the table for
the rubber stopper, the cork stopper and the
antacid
– For this lab, you DO NOT taste any of the objects
QUANTITATIVE MEASUREMENTS
• Record the quantitative measurements for the
rubber stopper and the cork stopper and
complete the table
– Mass
– Volume
DENSITY
• State the density formula
• Perform the density calculation for both
stoppers
LAW OF CONSERVATION OF MASS
• The Law of Conservation of Mass states that in
a chemical reaction, the mass of the product
equals the mass of the reactants
ANTACID
• Perform the qualitative observations of the
antacid
• What happens to the mass when antacid is
placed into a sealed bag?
CLEAN UP
• CLEAN UP AROUND YOU
• LEAVE THE TRIPLE BEAM BALANCE AT THE DESK
• DUMP OUT THE WATER INTO THE SINK FROM
THE ZIP LOCK BAG AND THROW AWAY THE ZIP
LOCK BAG
• BRINK THE GRADUATED CYLINDERS, STOPPERS
AND BEAKERS BACK TO THE LAB TAPLE AND
SEPARATE INTO ITS INDIVIDUAL GROUPS