Basic Laboratory Techniques

Question 1

is the actual amount of material in an object and does not change with the environment on which it is located

Answer 1

Mass

Question 2

is a force resulting from the interaction of the mass with the earth’s gravitational field and varies with location.

Answer 2

Weight

Question 3

Different types of balances or weighing scales are available to measure the mass of a sample

Answer 3

Analytical Balance
Triple beam Balance
Top Loading Balance

Question 4

have a complex system of electronic sensors to measure mass and are essential for weighing to milligrams quantity.

Answer 4

Electronic balances

Question 5

uses counterweights to determine the mass of a sample in its pan.

Answer 5

Triple beam balance

Question 6

____ of the balance is also essential to ensure accuracy of mass readings.

Answer 6

Periodic calibration

Question 7

Graduated cylinders, pipettes, burettes and volumetric flasks are generally used for measuring

Answer 7

Volumes of liquids

Question 8

pipettes and burettes are calibrated to deliver a

Answer 8

specific volume of liquids at a specified temperature.

Question 9

is the curve formed at the upper portion of the liquid.

Answer 9

Meniscus

Question 10

A ___ meniscus occurs when molecules of liquid are attracted more strongly with the surface of the container (adhesion)

Answer 10

concave

Question 11

A ___ meniscus occurs when molecules of liquid are attracted more strongly with the surface of the container (adhesion)

Answer 11

concave

Question 12

a ____ meniscus occurs when the molecules of liquid are more strongly attracted to each other (cohesion).

Answer 12

Convex

Question 13

should be used in conjunction with a rubber bulb to draw up liquid
from a container.

Answer 13

Measuring pipette

Question 14

the most basic of the three and has no needle valve that regulates gas flow.

Answer 14

Bunsen burner

Question 15

have a needle valve below to regulate the gas supply.

Answer 15

Tirrill burner and Meker burner

Question 16

differs in the presence of a screen on the top of the burner that forms many short, small uniform blue flames cones with a higher temperature. It is therefore more suited for glass blowing and other heating operations that require higher temperature.

Answer 16

Meker burner

Question 17

Solid and liquid chemicals are usually kept in ____

Answer 17

reagent bottles

Question 18

are used for light-sensitive chemicals to prevent them from decomposition.

Answer 18

Dark reagent bottles

Question 19

are used for light-sensitive chemicals to prevent them from decomposition.

Answer 19

Dark reagent bottles

Question 20

solid chemicals should be taken from a reagent bottle using a clean and dry

Answer 20

spatula

Question 21

is a process that is used to separate an insoluble solid from a liquid

Answer 21

Filtration

Question 22

insoluble solid is commonly termed as

Answer 22

residue or sediment

Question 23

insoluble solid is commonly termed as residue or sediment and if it is a result of a precipitation reaction, it is called

Answer 23

precipitate.

Question 24

insoluble solid is commonly termed as residue or sediment and if it is a result of a precipitation reaction, it is called

Answer 24

precipitate.

Question 25

The liquid portion is (in filtration)

Answer 25

filtrate

Question 26

is done to isolate a valuable residue that is to remove impurities and to recover filtrate as a valuable component

Answer 26

Filtration

Question 27

can be cut into smaller size using a triangular file

Answer 27

Glass tubing

Question 28

The glass tube is laid flat on the laboratory table and a _____ scratch at the point to be cut is made using the file.

Answer 28

circular

Question 29

A ___ scratch is preferable to lessen the pressure needed to break the glass.

Answer 29

deeper

Question 30

The sharp edges of the glass tube is polished by rotating it at the non-luminous portion of a laboratory burner’s flame ; the process is called

Answer 30

Fire polishing