CHEM 1120 Lab 7: Complete Lab Guide, Procedure & Analysis (ECU Chemistry
2026)
When heating a solution to boiling on a hot plate, start by starting and stabilizing the stir
function. Then, turn the heat to a medium heat setting to start. If necessary, turn up the heat
setting after waiting about ten minutes without seeing boiling.
Explanation - ANS ✔✔Explanation
When heating a solution to boiling on a hot plate, start by setting up the solution to stir. Make
sure that the stirring is stable before proceeding to turn on the heat. The stirring helps evenly
distribute the heat as you continue.
Then, start the heat at a medium setting. You can adjust the heat either up or down if you start
in the middle. Starting too low could make the boiling require a lot of extra time, especially if
you are heating an aqueous solution. Starting the heat at the highest setting could cause
thermal shock that damages the glassware or the hot plate.
If you wait ten minutes and don't see boiling yet, turn the heat up on the hot plate. Do not stop
the stirring function while heat is being applied.
While setting up a beaker to boil a solution on a hot plate, you notice that the stirring is erratic
and unstable. What should you do to stabilize the stirring solution? - ANS ✔✔Move the beaker
to the center of the hot plate.
Turn down the stirring speed.
If the stirring is erratic, make sure that the beaker is placed in the middle of the hot plate, where
the magnet is located. Also, turn down the stirring speed to allow the stir bar to reconnect with
the magnetic field that causes stirring.
When heating a beaker to boiling, you should make sure that the solution is stirring. The motion
of stirring helps evenly distribute the heat. When available, stirring a heating solution is superior
to boiling chips. Therefore, do not turn off the stirring function while heating.
It can be helpful to stabilize a beaker with a clamp during a heating procedure. However, the
beaker needs to be aligned with the middle of the hot plate for the best stirring.
, Which types of hazards can a fume hood help protect the user against? - ANS ✔✔Fumes
Fires
Explosions
Identify the term that matches each definition. - ANS ✔✔Be sure to become familiar with the
components and operation of a fume hood prior to use.
The front vent of a fume hood, which helps maintain proper air circulation= airfoil
The glass panel in front of the fume hood that shields the user from fumes and other hazards =
sash
The horizontal, flat area of a fume hood upon which experiments are carried out = work surface
A characteristic that describes substances that evaporate readily, producing large amounts of
vapors = volatile
When performing a melting point determination, how should you report your findings? - ANS
✔✔As a range from the temperature when melting starts to the temperature when it ends
The experimental melting point should be reported as the range from the temperature when
melting starts to the temperature when it ends. All of this information is necessary to
characterize the material, as the size of the range indicates the purity of the sample.
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube
into the sample with the open end of the tube down. Continue tapping until the sample is a
couple millimeters high.
Then, with the closed end of the tube down, tap the sample down slowly or drop the tube into
a longer tube to move the sample down faster.
2026)
When heating a solution to boiling on a hot plate, start by starting and stabilizing the stir
function. Then, turn the heat to a medium heat setting to start. If necessary, turn up the heat
setting after waiting about ten minutes without seeing boiling.
Explanation - ANS ✔✔Explanation
When heating a solution to boiling on a hot plate, start by setting up the solution to stir. Make
sure that the stirring is stable before proceeding to turn on the heat. The stirring helps evenly
distribute the heat as you continue.
Then, start the heat at a medium setting. You can adjust the heat either up or down if you start
in the middle. Starting too low could make the boiling require a lot of extra time, especially if
you are heating an aqueous solution. Starting the heat at the highest setting could cause
thermal shock that damages the glassware or the hot plate.
If you wait ten minutes and don't see boiling yet, turn the heat up on the hot plate. Do not stop
the stirring function while heat is being applied.
While setting up a beaker to boil a solution on a hot plate, you notice that the stirring is erratic
and unstable. What should you do to stabilize the stirring solution? - ANS ✔✔Move the beaker
to the center of the hot plate.
Turn down the stirring speed.
If the stirring is erratic, make sure that the beaker is placed in the middle of the hot plate, where
the magnet is located. Also, turn down the stirring speed to allow the stir bar to reconnect with
the magnetic field that causes stirring.
When heating a beaker to boiling, you should make sure that the solution is stirring. The motion
of stirring helps evenly distribute the heat. When available, stirring a heating solution is superior
to boiling chips. Therefore, do not turn off the stirring function while heating.
It can be helpful to stabilize a beaker with a clamp during a heating procedure. However, the
beaker needs to be aligned with the middle of the hot plate for the best stirring.
, Which types of hazards can a fume hood help protect the user against? - ANS ✔✔Fumes
Fires
Explosions
Identify the term that matches each definition. - ANS ✔✔Be sure to become familiar with the
components and operation of a fume hood prior to use.
The front vent of a fume hood, which helps maintain proper air circulation= airfoil
The glass panel in front of the fume hood that shields the user from fumes and other hazards =
sash
The horizontal, flat area of a fume hood upon which experiments are carried out = work surface
A characteristic that describes substances that evaporate readily, producing large amounts of
vapors = volatile
When performing a melting point determination, how should you report your findings? - ANS
✔✔As a range from the temperature when melting starts to the temperature when it ends
The experimental melting point should be reported as the range from the temperature when
melting starts to the temperature when it ends. All of this information is necessary to
characterize the material, as the size of the range indicates the purity of the sample.
To prepare a sample in a capillary tube for a melting point determination, gently tap the tube
into the sample with the open end of the tube down. Continue tapping until the sample is a
couple millimeters high.
Then, with the closed end of the tube down, tap the sample down slowly or drop the tube into
a longer tube to move the sample down faster.
