Activity 2 Flashcards
In case of a fire due to a gas leakage, immediately turn off the ___
To prevent spreading of the fire, cover it with ___ or ___
Gas Tank Regulator
Sand, wet cloth
Most Chemical spills are best handlled by quickly absorbing the wet material with ___ and then washing the area with ___
paper towels
water
To neutralize acid on clothing use ___
To neutralize base on clothing use ___
To neutralize any on desk use ___
dilute sodium bicarbonate solution
boric acid solution (50g/L)
solid sodium bicarbonate + water
Why do you never lay a stopper of a reagent bottle on the laboratory bench?
Because it will pick up impurities and contaminate the solutions
How do you transfer liquids to another container
Hold a stirring rod against the lip of the container holding the liquid
pour it down the rod which is touching the inner wall of the receiving vessel
A solution’s volume is read at which part of the meniscus?
The bottom of the meniscus
A Test tube should be no more than ___ full
An Erlenmeyer Flask should be no more than ___ full
A large beaker used as a bath must be no more than ___ full
one-third
one-fourth
one-fourth
What is ebullition?
A sudden violent outburst from a liquid
How do you stop bumping? (sudden formation of superheated liquid near flame)
the flame must directly be under the top of the stirring rod.
you may place a second supporting ring around the top of the beaker to prevent it from being bumped off
For the evaporation of liquids:
Nonflammable liquids are evaporated in a ___ with a ___
Flammable liquids are evaporated with a ___, perhaps with a ___
evaporating dish, gentle direct flame/steam bath
heating mantle/fume hood
How do you transfer a solid reagent?
Hold the bottle with the label against your hand, tilt, and ROLL
A liquid the supernatant can be decanted (poured off the top) when?
from a solid if there is clear separation
Using a beaker in decantation what can you do?
Can be tilted to allow the solid to settle at the side with an item
How fast does a centrifuge spin?
5000 to 25 000 revolutions
Centrifuge rules (4)
Never fill the centrifuge tubes to a height more than 1 cm from the top
label the centrifuge tubes to avoid confusion
Operate the centrifuge with even number of centrifuge tubes with equal volumes of liquid
Never manually stoop the centrifuge
