Science 6

2. MeasuringVolume
Place the graduated
cylinder onaleveled
workingarea.
Make surethat the liquid
meniscusis ateye level.
Forclearsamples you
shouldreadatthe lower
meniscusandfordark-
coloredliquid samples,
the uppermeniscus.

4. USING PIPET
Two typesof pipet:
1. volumetricpipet–
deliverspecific
amount of liquid
sample
2. graduated pipet–
deliverany amount
of amplejust likethat
of a graduated
cylinder.

Rubber aspirator – draw liquid sample into a pipet.
 Steps in using volumetric pipet:
1. Fill in the pipet with the use of the rubber aspirator
above the calibration mark.
2. Remove the rubber aspirator and immediately cover
the top of pipet with your index finger.
3. Adjust the level of the meniscus by releasing slightly
your right index finger.
4. Drain freely the content of the pipet to the receiver
by removing the right index finger.

5. Measuring
mass
1. Make sure that the measuring tray is free of any
undesirable debris.
2. Place all the riders to zero position and check if the
pointer is aligned to the zero mark.
3. If not, use the adjustment knob to position the
pointer to zero.
4. Do not place the chemicals directly on the balance
pan. Place your samples on a weighing vessel or
proper container.
5. Moves first the hundreds rider. If the pointer drops
below the zero marker, move the rider back to its
original position. Do the same for the tens and the
ones until pointer aligns to the zero marker. Read the
mass of the sample by adding the positions of the
rider.

6.  5. remove the sample and return to the original position.
PARTS OFTHETRIPLE BEAM BALANCE

7. PROPERUSE
OF
ANALYTICAL
BALANCE
1. Clean the balance before you weigh any sample.
2. Do not place the chemicals directly on the balance pan. Place
your sample on a weighing vessel or proper container.
3. Make sure that the windows of the balance are closed before
any measurement is made.
4. The analytical balance has “rezero” or “tare” function. Place
your weighing vessel on the pan and press this function.Wait
for the digital readout 0.0000 before you add any chemicals.
The digital readout that will appear will be the weight of the
chemicals alone.
5. Never weigh samples that are hot for they will damage the
electronic parts of the balance.
6. In determining the mass of liquid samples, do not add the
sample while the vessel is inside the analytical balance.
7. Always clean the balance after use.

9. USINGTHE
BUNSEN
BURNER
1. Make sure that the rubber tubing connected to the gas inlet is
secured and not damaged.
2. Close the needle valve and the air ports and their parts after
which connect the rubber tubing to the gas outlet.
3. Have your matches ready before opening the gas outlet.
4. Slowly open the needle valve to admit fuel and adjust the
height of the flame as desired. At this point, the flame may be
yellow and this is referred to as the “luminous flame”.A
luminous flame is not used for heating purposes. A
nonluminous flame or blue flame is ideal.
5. To obtain a nonluminous flame, adjust the air port so as to
admit more air that will mix with the fuel for complete
combustion. Complete combustion will take place thus creating
a nonluminous flame.

10. HEATING
LIQUID
SAMPLES
- uses
burner/alcohol
lamp/heating man,
and tripod, if using
tripod needs wire
gauze

11. TRANSFERRING
REAGENTS
FROMONE
CONTAINERTO
ANOTHER
SOLID
1. Remove the cover of the reagent bottle (make sure that the
cover dis not touch any surface.
2. Use either porcelain or metal spatula to obtain sample.
(corrosive chemicals must used porcelain spatula.
3. If there is no spatula, simply tilt the reagent bottle around 45o
and rotating the bottle back and forth. Make sure that the
receiver is clean to avoid contamination.
LIQUID
1. Use a dropper or pipet.
2. Make sure that the tip of the dropper and the pipet did not
touch the receiver bottle to avoid contamination.
3. It can be also be poured to another container (CAREFULLY).A
glass rod is used to guide the flow of liquid.

12. SEPARATION
TECHNIQUES
- Greatly used in separating mixtures
- Mixtures contain two or more pure substances.

13. DECANTATION
 Fast means of separating liquid from heavier solid particles.
 The mixture is allow to stand for some time to allow the heavy
particles settle down.
 Liquid (also known as decantate), is slowly poured our to separate
from the solid particles.
 Not applicable to solids that re light and fine.

14. FILTRATION
 Mixtures of solid and liquid can used this technique
 Applicable to lighter and finer solid particles.
 It uses filter paper

16. CENTRIFUGAT
-ION
 Mixture that its solid particles are too small that even decantation
and filtration cannot do the separation.
 Mixture is placed in a centrifuge tube and allowed to spin at a
specific speed and time.
 The finer solid particles clump together at the bottom of the
centrifuge tube and the liquid sample can be removed either with
decantation or with the use of dropper.

19. DISTILLATION
 This technique is based on differences in boiling point of the
components of the mixture.
 As the mixture is heated, the component with lower boiling point
will evaporate, condense and collected in the receiving vessel first
leaving behind the components with higher boiling point.

20. CHROMATO-
GRAPHY
 Separates the components of
mixtures based on the affinity
of the components to two
phases: the stationary and
mobile phase.
 MOBILE PHASE – consists of
the mixture and the solvent that
moves the mixture through the
column.
 STATIONARY PHASE – system
in which the mobile phase flows
and where the distribution of
the components of the mixture
occurs.
 Common type of
chromatography is PAPER
CHROMATOGRAPHY.

21. READING
LABELSON
CHEMICAL
BOTTLE
THESE ARETHE GENERAL LABELSTHAT NEEDSTO BE
READ BEFORE USINGTHE CHEMICALS.
 Name of contents
 Chemical composition
 Statement of possible hazards and precautionary
measures
 Instruction in case of Contact or Exposure
 Date prepared
 Manufacturer