Lab E1

Question 1

Preparative work does not need a precise measurement but there is a type of procedure used to determine the approximate mass of the analyte in that is within the specified range within a certain procedure.

Answer 1

Rough Weighing

Question 2

used to obtain an approximate mass that is within the range specified by the procedure.

Answer 2

Top-loading Balance

Question 3

Used for accurate weighing

Answer 3

Analytical Balance

Question 4

Highly sensitive instrument that is much more prone to errors from environmental conditions and requires much careful operation than a top-loading balance.

Answer 4

Analytical Balance

Question 5

Used for +-0.0001 g. and is used when a very accurate mass determination is needed.

Answer 5

Analytical Balance

Question 6

is determined by the spirit level, leveling bubble, or plump blob that is integral part of the balance.

Answer 6

Reference position

Question 7

what is the shield that covers analytical balance against air currents that may hinder it?

Answer 7

Draft Shield

Question 8

This is a plastic or glass enclosure with doors that allows access to the pan

Answer 8

Draft Shield

Question 9

Mass of the empty vessel

Answer 9

Tare

Question 10

Automatically adjusted the Analytical Balance to read the mass of zero.

Answer 10

Tare

Question 11

Procedure if the sample is then transferred to the container and the new mass is measured.

Answer 11

Direct Weighing

Question 12

When two sample are first put, the analyte and the container, then after the analyte was removed, the container was weighed.

Answer 12

Weighing by difference

Question 13

What should be regularly assessed in Analytical Balance?

Answer 13

Accuracy
Repeatability
Cornerload
Linearity
Drift

Question 14

Ensures that the analytical balance deliver accurate results consistent for a given object.

Answer 14

Repeatability Measurement

Question 15

The ability of the instrument to generate the same readings for an object, regardless of where it is placed on the weighing pan.

Answer 15

Cornerload

Question 16

Ensures that the weighing instrument is delivering the same sensitivity throughout its functional range.

Answer 16

Linearity

Question 17

What causes drifts of analytical balance, basing on the operating conditions?

Answer 17

Temperature
Humidity
Build-up of static electricity

Question 18

Is the first step of any quantitative analytical chemical method.

Answer 18

Weighing the Analytical Sample

Question 19

Experiment questions:

1. What are the steps/techniques in using the analytical balance?

a) prior to weighing
b) during weighing
c) after weighing

2. What are some of the determinate and indeterminate sources of errors in weighing?
3. Why do we need to calibrate equipment such as analytical balance prior to doing measurement?