Which type of glassware is specifically calibrated to 20 degrees Celsius?

Class A glassware is specifically calibrated to 20 degrees Celsius, which makes it highly accurate for precise measurements. This type of glassware is manufactured to strict tolerances, ensuring that the volume stated on its markings is accurate at this standard temperature, allowing for reliable and reproducible laboratory results.

Class A glassware is often used in analytical procedures where precision is critical, such as in titrations or when preparing standard solutions. The calibration at 20 degrees Celsius accounts for potential variations in volume caused by temperature changes, thereby providing consistency in measurements.

In contrast, Class B glassware has a wider tolerance for volume accuracy and is not as reliable for precise work, which is why it isn't calibrated specifically to a set temperature like 20 degrees Celsius. Other choices, such as refrigerated or flexible glassware, do not pertain to this calibration standard, further confirming the distinction and purpose of Class A glassware in laboratory settings.