COMMON LABORATORY TECHNIQUES | 3.2

meniscus / lowest point

The surface of water in a glass tube is curved upward. This curved surface

is called the ****. In reading the volume, keep your eye at the same

level as the ****** *****.

rubber bulb aspirator

It resembles a buret but often a bulb is blown in the stem to accommodate a greater volume.

To draw liquid into the pipet, use a **********.

Buret

cylindrical glass tube with graduations along its side

and with provision for drawing liquid through a small opening at the end.

NEVER return any excess liquid

sample to its original container!

Obtaining the liquid sample directly from the bottle is strictly

prohibited to prevent contamination. Instead, transfer a small

portion into a small beaker. ******************************** Try to find someone else who

needs it before disposing it.

top loading balance

The most common type of balance found in the laboratory is the**** *** *****.

brush

Note: If you spill a chemical on the balance pan, use the **** to clean

the balance pan IMMEDIATELY! Chemicals left on the balance pan

will corrode the pan.

opposite

Always pour the liquid from a bottle on the side **** the label,

especially if the bottle has a paper label. If you spill any liquid or drip some

on the side of the bottle, clean it up. Never put chemicals taken out back

into the reagent bottle since they may have become contaminated.

1 to

2

The beaker or flask and its contents should be supported about ****** ****** inches above the burner by an iron ring on a ring stand.

wire gauze

The beaker or flask and its contents should be supported about 1 to

2 inches above the burner by an iron ring on a ring stand. A ***** **** should always be placed between the beaker (supported by

the ring) and the flame to prevent the glass from breaking due to

unequal heating.

precipitate

When substances in solution interact to form a solid that is insoluble or

only very slightly soluble, a ****** is said to have been formed.

decantation

The process of separating a liquid from a dense insoluble substance by

simply pouring off the liquid is called *****.

supernatant

The liquid above the

precipitate, which is poured off during decantation, is called the

***** liquid.

filtration

The separation of a solid from a liquid by passing the liquid through a

membrane such as a filter paper is called *****.

filtrate / residue

The liquid that passes

through the membrane is called the ***** while the solids left are called

the *****.