Titrations allow us to determine the number of moles of a compound in a sample.

Here is the key equation to understanding a titration where the coefficients refer

to the balanced chemical equation of the titrant reacting with the analyte:

Buret Introduction

For a titration to be quantitative, we need to determine how many moles of

titrant we have added. A buret is a commonly used piece of scientific equipment

to quantify the volume of liquid that has been delivered. We put a solution into

the buret that has a known molarity. We then determine the number of moles by

The buret has three main parts: 1. The tip of the buret is

where the liquid leaves the end of the buret, 2. The

stopcock is the valve near the tip of the buret that starts

and stops the flow of liquid from the buret, and 3. The neck

of the buret has volume markings that allow us to

determine how much liquid has left the buret.

When you are reading a buret, it is critical to make sure

that you take the time to look closely at the markings and

understand the spacing. In the picture in Figure 6.2 each

milliliter is marked (19, 20, 21, and 22). In addition, there

are nine lines in-between each milliliter value, so each of

these lines represents one-tenth of a milliliter. When

reading the buret in Figure 6.2, I see that the bottom of the

meniscus is in between the 1^st and 2^nd line after the 20 mL

mark. Notice that the bottom of the meniscus is likely to

not fall exactly on a marking which allows us to interpolate

the value to get the correct value along with an estimate of

the uncertainty.

My thought process for reading the buret is first to note

that the value is somewhere between 20 and 21 mL; then I

go a step further and see it is between 20.1 and 20.2 mL,

finally I determine the recorded value by estimating the last

digit. It looks as if it is closer to 20.2 mL than 20.1 mL so I

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Figure 6.1: 50 mL buret.