CHM 161 midterm

What are the best practices for safely handling waste in the lab?

-Always wear appropriate Personal Protective Equipment -Check labels or instructions before any disposal

What should you do every time you are about to heat glassware on a hot plate?

-Check that there are no cracks in the glassware -Ensure that the glassware is designed for heating -Inspect the hot plate for frayed cords

Which signs are typically posted in areas of active lab work?

-Personal protective equipment (PPE) sign -Safety equipment signs -Sign prohibiting food and drink -Chemical storage signs

Which steps are necessary for cleaning a spill involving broken glass?

-Pick up large pieces of glass with gloved hands -Soak up any spilled liquid with absorbent material. -Stop the spread of the spill.

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?

-Turn down the stirring speed. -Move the beaker to the center of the hot plate.

All lab participants must remain prepared to use safety equipment in case of emergency. Identify the components of effective preparation.

-Understanding where the safety equipment is located -Being familiar with how safety equipment is used -Knowing what safety equipment is available

When heating a solution to boiling on a hot plate, start by _________ Then, turn the heat to _______ to start. If necessary, __________ after waiting about ten minutes without seeing boiling.

-starting and stabilizing the stir function -a medium heat setting -turn up the heat setting

Identify the step that is not recommended when responding to an emergency.

Gather your belongings

Which procedure cannot be performed on a hot plate, requiring a Bunsen burner instead?

Heating a crucible to remove water from a hydrate

Review the Safety Data Sheet (SDS) for potassium hydroxide, then identify the best course of action for each type of chemical exposure.

If inhaled.....Move person to fresh air. If swallowed.....Rinse mouth with water. In case of skin contact.....Take off any contaminated clothing and rinse thoroughly In case of eye contact......Rinse with water for 15 minutes.

What information is necessary to review in order to be considered familiar with the Safety Data Sheet (SDS) of a substance?

-Handling, storage, and reactivity information -Personal protection and first aid recommendations -Hazard warnings -Identification and description of substance

Which types of signs are posted to convey information about chemical storage?

-Hazard signs such as "Flammable," "Oxidizer," and "Corrosive" -National Fire Protection Association (NFPA) diamond -Gas Cylinder sign

How should students prepare to use chemicals in the lab?

-Locate the spill kits and understand how they are used -Become familiar with the chemicals to be used, including exposure or spill hazards

When using a properly stabilized balance, how should you ensure that you get the most accurate mass reading possible?

-Measure the mass of the sample at room temperature. -Close the side shields on the balance during reading

When an alarm sounds in the laboratory, it is important to respond _________ and remain ___________. Listen for any other instructions, turn off any ______________ in use, and be prepared to leave immediately.

calmly, quiet, equipment

In general, which characteristics are necessary for a location to be suitable for chemical storage?

cool, dry, dark

Changing gloves often will minimize the spread of chemicals. To properly remove gloves, first,

grasp the exterior of one glove with a gloved hand; then peel off the first glove. Then insert a bare finger between the interior edge of the second glove and the skin, and remove the second glove.

Determine the best way to deal with each of the following items that may dangle into the way during lab work.

long earrings: Remove long hair: tie back and secure flowly sleeves: tie back and secure loose bracelets: remove long necklaces: remove

In case of accidental contact with chemicals, how long should the eyes be flushed at the eyewash station?

15 minutes

What information does not need to be included a chemical waste label?

A description of the experiment the chemicals were used for

Determine when to put on disposable gloves for work in the lab.

Before handling any glassware or chemicals for the experiment

A student removes a chemical sample from a reagent bottle to be used in an experiment. What should he do with any excess chemical remaining from this sample after the experiment is complete?

Check and see if anyone else can use the chemical. If not, discard in the proper waste container.

Which chemical waste situation should always be supervised or performed by an instructor? Note that you still may need to alert your instructor about the described incident, even if you clean it up yourself

Cleaning up a broken mercury thermometer

What should you do if you are using a balance that has persistent fluctuations in mass?

Contact your TA or instructor to adjust the balance.

It is often helpful to remember the acronym PASS when using a fire extinguisher. Fill in the word that corresponds with each letter to complete the steps needed for operation of this device.

P: pull the pin A: Aim the nozzle at the base of the fire S: squeeze the lever slowly S: sweep the spray from side to side over the fire

Determine the safest option in the lab if you need your vision to be corrected

Wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your TA or Instructor for your school's policy

Determine when you should remove your goggles in the lab room.

When everyone in the room is done handling any chemicals or glassware

When should you start a new chemical waste container in the lab?

When the contents of the current container are a couple inches below the brim of the container

Match each lab incident to the item of PPE that will protect you from it. Each item of PPE will only be used once.

While checking on a stirring solution, the solution splashes up towards your face. (goggles) While pulling an empty beaker off the shelf at the beginning of lab, it slips out of your hand onto the floor. (closed-toe shoes) While transferring a solution from a flask to a beaker, the solution accidentally spills down the front of the lab bench. (lab coat) While picking up a buret, an unknown solution left by a previous solution drips onto your hand. (gloves)

To experimentally determine Avogadro's number, you can apply a current to a metal circuit, causing the metal to lose electrons and dissolve as ions. The number of moles of electrons lost from the metal can be calculated from the _______ of the metal as well as ________ in each ion formation. The total number of electrons involved in the process can be calculated from the __________ and the individual charge of an electron. Then, Avogadro's number is the ________ divided by the ________.

mass change and molar mass the number of electrons lost total charge applied total number of electrons number of moles of electrons

In the plot to determine Avogadro's number, the x-axis should be ________ and the y-axis should be _________. The _________ of the best-fit line should be Avogadro's number.

moles of electrons number of electrons slope

Suppose you light a Bunsen burner and notice that the flame is very yellow and too short. To get a blue flame, you should _______ the ______ further. To increase the size of the flame, you should ________ the _______ further.

open, air inlet open, gas regulator