PHA612 - LAB - LAB TECHNIQUES (separate) Flashcards
In Filtration, ensure that the small test tube to be used should NOT be more than ____.
3/4 full
TRUE OR FALSE.
In Filtration technique, you should BALANCE the centriduge SYMMETRICALLY
TRUE
Position another test tube with the same amount of liquid on the opposite cup of the centrifuge
TRUE OR FALSE.
In Filtration, when using the centrifuge, you should allow the machine to stop by itself
TRUE
In precipitation technique, you should add the precipitating reagent ____ with constant ______
dropwise;
stirring/flicking
To test for the completeness of precipitation. Provide the 5 steps
- To the clear supernatant liquid, add 1 – 2 drops
of the precipitating reagent - Precipitation is complete if no more
precipitate is formed - In case of precipitation or turbidity, add a few
drops more of the precipitating reagent - Stir and centrifuge again
- Repeat procedu
In the test for completeness of precipitation, precipitation is complete if _____?
if no more precipitate is formed
This laboratory technique, separates the precipitate from the supernatant liquid
Decantation
TRUE OR FALSE
In Decantation technique, it is always important to COMPRESS THE BULB of a dropper/pipet BEFORE inserting the tip inside the test tube.
TRUE
Compressing the bulb WHILE inside the tube, will create bubbles
bubbles are considered as a form of contamination
TRUE OR FALSE, In a Decantation Technique, you should lower the tip as the level of the solution drops
TRUE
In a decantation technique, what should you do when the solution nears the precipitate?
You should slightly titlt the tube
In washing the precipitate you should add the required amount of ____ or ____ to the solid.
distilled water; wash solution
TRUE OR FALSE
In washing the precipitate;
Stir, centrifuge and decant the wash liquid
TRUE
In washing the precipitate, the first portion of the washing is combinwed with the _________
supernatant liquid
In washing the precipitate, the second portion is ________
discarded
In testing of the solubility of precipitate, Name the 3 step process to test this.
- Add dropwise the specified reagent to the precipitate
- Stir the mixture and observe the quantity of the precipitate
- If the amount decreases, continue adding the reagent until the precipitate dissolves
TRUE OR FALSE
In using a water bath, you should use a 250 mL beaker, 2/3 filled with water.
TRUE
TRUE OR FALSE
In the use of sand bath, you should place the mixture in a large vessel
FALSE. SMALL VESSEL
In the use of sand bath, you should position the small vessel in a bigger vessel that is _____ filled with sand
2/3 filled with sand
TRUE OR FALSE
The use of sand bath is for solutions which required temperature HIGHER than 100 degrees Celsius
TRUE
In Evaporation Technique, you should use a ________ and heat over a wire gauze using a small flame.
small porcelain casserole
TRUE OR FALSE. Evaporation Technique should be conducted WITHOUT BOILING
TRUE
This process is under what technique:
- Remove the casserole from the flame while there is still a drop or two of the liquid left
* Heat in the casserole will complete the evaporation
Evaporation to Dryness
In Precipitation with Hydrogen sulfide gas, you should add how many drops of CH3CONH2 to the solution?
10 drops 10% CH3CONH2
We add the drops of CH3CONH2 to the solution to be saturated with __?
H2S
TRUE OR FALSE
In Precipitation with Hydrogen sulfide gas, you should Stir the mixture and heat in a water bath for 10 minutes
TRUE
TRUE OR FALSE. In a flame test, the wire is dipped in the acid/compound again to be tested and place back in the flame
TRUE
Flame Test uses what 2 types of wire?
- Clean Platinum
- Nichrome wire
In a flame test, where should you place the wire until no color is produced?
Non-luminous flame
We use the Buchner Funnel to speed up the rate of ???
rate of filtration
TRUE OR FALSE
Buchner Funnel are used for products with fine and voluminous precipitate
TRUE
TRUE OR FALSE
Buchner Funnel are designed for vacuum decantation
FALSE. Vacuum FILTRATION
What laboratory equipment to use when working on an experiment that involves gases?
This is also known as a gas chamber
Watch glasses
TRUE OR FALSE
Attach a piece of filter paper moistened with the reagent to the concave surface of the upper watch glass
and then
Place the reaction mixture on the lower watch glass
TRUE
TRUE OR FALSE
Work involving gases, uses 2 watch glasses in contact with each other.
TRUE
