Is a specific configuration of atoms commonly attached to the carbon skeletons of organic molecules and usually involved in chemical reaction.

The answer is "Functional Group"

Explanation: A Functional Group is the arrangement of atoms that characterizes a family of compounds. Commonly is distinguished by different atoms nearly or rounded a carbon atom. Is like the principal actor in a chemical reaction.

For example:

In the picture we can see an Organic Acid named Acetic Acid (commercially known as vinegar). Its functional group (red circle) is -COOH, that means, this arrangement of atoms is the one that characterizes the carboxilyc acids in organic molecules.

the answer

explanation:

the capillary tube was too close to the bottom of the beaker.

the ruler may have moved.

water got into the capillary tube.

the temperature was not allowed to equilibrate in the 2-4 minutes.

where's the diagram?