A student obtained a clean, dry glass-stoppered flask. She weighed the flask
and stopper on an analytical balance and found the total mass to be \(33.695
\mathrm{g}\). She then filled the flask with water and obtained a mass for the
full stoppered flask of \(64.356 \mathrm{g}\). From these data, and the fact
that at the temperature of the laboratory the density of water was 0.9978
\(\mathrm{g} / \mathrm{cm}^{3},\) find the volume of the stoppered flask.
a. First we need to obtain the mass of the water in the flask. This is found
by recognizing that the mass of a sample is equal to the sum of the masses of
its parts. For the filled stoppered flask:
Mass of filled stoppered flask = mass of empty stoppered flask + mass of
water, so mass of water \(=\) mass of filled flask - mass of empty flask
Mass of water \(=\) ________ g- ________ g= __________g
Many mass and volume measurements in chemistry are made by the method used in
la. This method is called measuring by difference, and is a very useful one.
b. The density of a pure substance is equal to its mass divided by its volume:
Density \(=\frac{\text { mass }}{\text { volume }}\) or volume \(=\frac{\text {
mass }}{\text { density }}\)
The volume of the flask is equal to the volume of the water it contains. Since
we know the mass and density of the water, we can find its yolume and that of
the flask. Make the necessary calculation.
Volume of water = volume of flask = _____________ \(\mathrm{cm}^{3}\)
