PHA612 - LAB - LAB TECHNIQUES (separate)

Question 1

In Filtration, ensure that the small test tube to be used should NOT be more than ____.

Answer 1

3/4 full

Question 2

TRUE OR FALSE.
In Filtration technique, you should BALANCE the centriduge SYMMETRICALLY

Answer 2

TRUE

Position another test tube with the same amount of liquid on the opposite cup of the centrifuge

Question 3

TRUE OR FALSE.
In Filtration, when using the centrifuge, you should allow the machine to stop by itself

Answer 3

TRUE

Question 4

In precipitation technique, you should add the precipitating reagent ____ with constant ______

Answer 4

dropwise;
stirring/flicking

Question 5

To test for the completeness of precipitation. Provide the 5 steps

Answer 5

1. To the clear supernatant liquid, add 1 – 2 drops
   of the precipitating reagent
2. Precipitation is complete if no more
   precipitate is formed
3. In case of precipitation or turbidity, add a few
   drops more of the precipitating reagent
4. Stir and centrifuge again
5. Repeat procedu

Question 6

In the test for completeness of precipitation, precipitation is complete if _____?

Answer 6

if no more precipitate is formed

Question 7

This laboratory technique, separates the precipitate from the supernatant liquid

Answer 7

Decantation

Question 7

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.

Answer 7

TRUE

Compressing the bulb WHILE inside the tube, will create bubbles

bubbles are considered as a form of contamination

Question 8

TRUE OR FALSE, In a Decantation Technique, you should lower the tip as the level of the solution drops

Answer 8

TRUE

Question 9

In a decantation technique, what should you do when the solution nears the precipitate?

Answer 9

You should slightly titlt the tube

Question 10

In washing the precipitate you should add the required amount of ____ or ____ to the solid.

Answer 10

distilled water; wash solution

Question 11

TRUE OR FALSE
In washing the precipitate;
Stir, centrifuge and decant the wash liquid

Answer 11

TRUE

Question 12

In washing the precipitate, the first portion of the washing is combinwed with the _________

Answer 12

supernatant liquid

Question 13

In washing the precipitate, the second portion is ________

Answer 13

discarded

Question 14

In testing of the solubility of precipitate, Name the 3 step process to test this.

Answer 14

1. Add dropwise the specified reagent to the precipitate
2. Stir the mixture and observe the quantity of the precipitate
3. If the amount decreases, continue adding the reagent until the precipitate dissolves

Question 15

TRUE OR FALSE
In using a water bath, you should use a 250 mL beaker, 2/3 filled with water.

Answer 15

TRUE

Question 16

TRUE OR FALSE
In the use of sand bath, you should place the mixture in a large vessel

Answer 16

FALSE. SMALL VESSEL

Question 17

In the use of sand bath, you should position the small vessel in a bigger vessel that is _____ filled with sand

Answer 17

2/3 filled with sand

Question 18

TRUE OR FALSE
The use of sand bath is for solutions which required temperature HIGHER than 100 degrees Celsius

Answer 18

TRUE

Question 19

In Evaporation Technique, you should use a ________ and heat over a wire gauze using a small flame.

Answer 19

small porcelain casserole

Question 21

TRUE OR FALSE. Evaporation Technique should be conducted WITHOUT BOILING

Answer 21

TRUE

Question 22

This process is under what technique:

1. 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

Answer 22

Evaporation to Dryness

Question 23

In Precipitation with Hydrogen sulfide gas, you should add how many drops of CH3CONH2 to the solution?

Answer 23

10 drops 10% CH3CONH2

Question 24

We add the drops of CH3CONH2 to the solution to be saturated with __?

Answer 24

H2S

Question 25

TRUE OR FALSE
In Precipitation with Hydrogen sulfide gas, you should Stir the mixture and heat in a water bath for 10 minutes

Answer 25

TRUE

Question 26

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

Answer 26

TRUE

Question 26

Flame Test uses what 2 types of wire?

Answer 26

1. Clean Platinum
2. Nichrome wire

Question 26

In a flame test, where should you place the wire until no color is produced?

Answer 26

Non-luminous flame

Question 27

We use the Buchner Funnel to speed up the rate of ???

Answer 27

rate of filtration

Question 28

TRUE OR FALSE
Buchner Funnel are used for products with fine and voluminous precipitate

Answer 28

TRUE

Question 29

TRUE OR FALSE
Buchner Funnel are designed for vacuum decantation

Answer 29

FALSE. Vacuum FILTRATION

Question 29

What laboratory equipment to use when working on an experiment that involves gases?

This is also known as a gas chamber

Answer 29

Watch glasses

Question 30

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

Answer 30

TRUE

Question 30

TRUE OR FALSE
Work involving gases, uses 2 watch glasses in contact with each other.

Answer 30

TRUE