Experimental Techniques

One of the first few topics you learn in O-Level Chemistry (and other basic Chemistry syllabuses) must be Measurement & Experimental Techniques.

The physical quantities that we usually measure are: Mass, Time, Temperature & Volume.

Out of them, measurement of volumes of liquids are considered one of the most important and we need to know the precision / accuracy of the different apparatus.

(Source: Unknown)

Let’s take a look at the different apparatus used for measurement of volumes of liquids:

Measuring Cylinder:

– Measures volumes to the nearest 0.5 cm³

Burette:

– Measures volumes of liquids to the nearest 0.05 cm³
– Used to deliver different volumes of liquids e.g. 24.00 cm³, 28.95 cm³, etc

Pipette:

– Measures out fixed volumes of liquids e.g. 20.0 cm³, 25.0 cm³, 50.0 cm³, etc

Gas Cylinder (BONUS):

– Measures volumes of gases

So far so good?

Let’s take a look at a question then.

Quick Check:

Given the following common laboratory apparatus:

• 100 cm³ measuring cylinder
• 100 cm³ beaker
• 50 cm³ gas syringe
• 50 cm³ burette
• 25 cm³ pipette
• Mass balance

From the common laboratory apparatus listed above, select the best apparatus to perform each of the following tasks. You may use any of the apparatus once, more than once or not at all.

(a) Measuring 60 cm³ of ethanol

(b) Measuring 25 cm³ of nitrogen

(c) Measuring 23.30 cm³ of dilute hydrochloric acid

(d) Transferring 25.0 cm³ of aqueous sodium hydroxide from a round bottom flask into a beaker

Go do it and leave your answer in the COMMENT section below.

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