Video Transcript
Which of the following is most
ideally measured by the item of labware shown in the image below? (A) Temperature of the air, (B)
concentration of an acid, (C) mass of a solid, (D) volume of water, or (E) volume of
a gas.
Let’s first identify some of the
defining characteristics of this item to determine its name and how it is used in
the lab, so that we can identify the answer choice that fits what is ideally
measured by this item. In the image provided, we can see
that the device contains tubing. When labware has tubing, this
generally means it will be connected to another device either for matter to enter or
exit the labware. Next, we can see a cylindrical
barrel that has gradations marked on its side. These gradations allow us to
measure with some level of precision. Both in and leading out of the back
of the barrel, we can see a plunger that is likely movable. Together, this plunger and barrel
make up a syringe.
Using this apparatus is not the
most convenient way to collect liquids, which can be measured using many other
pieces of equipment. Thus, this piece of labware is
called a gas syringe. This gas syringe could likely be
used to collect a gaseous product from a chemical reaction. Take, for example, the chemical
reaction between zinc and hydrochloric acid, which produces hydrogen gas and an
aqueous solution of zinc chloride. The reaction could be conducted in
an Erlenmeyer flask, which could also be called a conical flask, and contained in an
airtight manner, such as with a rubber stopper connected to the gas syringe
tubing.
As the hydrogen gas is produced, it
enters the syringe through the tubing and begins to move the plunger along the
barrel. Once the reaction is complete, the
volume of gas produced can be determined using the gradations. Therefore, the answer choice that
is most ideally measured by the item of labware shown in the image is answer choice
(E), volume of a gas.
