Why it is applicable to use a piece of paper when transferring solid chemicals to a test tube?

A clean, uncontaminated piece of paper is ideal for transferring dry chemicals to a scale for measuring weight and to a test tube where the paper can be bent or folded to act as a funnel, minimizing the possibility of spillage. The weight of the paper is minimal and if all the papers are identical, the weight can be predetermined to make weighing more accurate.

Paper can be thrown away after use. The alternative is using metal or glass utensils to transport chemicals and as a funnel to fill the test tube. They all need to be washed well and dried before being used again otherwise the chemicals transferred can be contaminated by whatever was last used on the utensil.