Question

 

1. Why should I not use the house air to dry my glassware?

2. Comment on whether ir not the correction volume is within the error allowed for each

Buret, volumetric, beaker, and erlenmeyer flask

Answer 1

1. The house air, the one at the room temperature is the one where most of the micro organisms dwell. This is not a healthy way of drying your glassware where the moist air can stick and cause problem when you use it. Therefore, they can either cleaned with wine or dried in the oven where the heat is good enough to kill the harmful bacteria.

2. The volume occupied by a given mass of liquid varies with temperature, as does the volume of the device that holds the liquid. 20^oC has been chosen as the normal temperature for calibration of much volumetric glassware.

Glass is a fortunate choice for volumetric ware as it has a relatively small coefficient of thermal expansion; a glass vessel which holds 1.00000L at 15^oC holds 1.00025L at 25^oC.

If desired, the volume values (V) obtained at a temperature (t) can be corrected to 20^oC by use of:

V₂₀ = V [1 + 0.000025 (20 - t)]

In most work, this correction is small enough it may be ignored. Thus, the correction would be too small and would be ignored for an error.