Question

If A chemist performed an experiment in Spain, how could she be sure that chemists in China could interpret the measures she obtained

Answer 1

Any number of ways, but the answer you're probably in search of is:

(1) Report the measurements using standardized units, such as the SI system of units.

(2) Follow standard rules on indicating precision of measurements by following the usual "significant digit" rules.

It would also generally be important to use the same symbols and names for the important constituents of the experiment. For example, you'd want to use the standard symbols for the elements -- C for carbon, K for potassium, O for oxygen -- and not make up your own. You'd want to write chemical formulas in the standard way, e.g. \[{\rm CO}_2\] and not \[{\rm O}^2{\rm C}\] or \[{\rm O}^{\prime \prime}{\rm C}\] or something like that. You'd want to call mass "mass" and density "density" and not vice versa, or call density "florglhups" or whatever word is convenient to you.

Broadly speaking, to be understood elsewhere, you need to speak the same language, or translate. Speaking the same language is less tricky, of course. And in science, there is the advantage that there are certain "languages" -- based on math -- which are extremely precise and unambiguous, so that you can much more easily create a "universal" language that everyone understands, a language much more "universal" than a lingua fraca like English or Latin, or than a designed universal language like Esperanto. Such languages in science are the SI System of units and measurement, the standard symbols for the elements, the IUPAC rules on chemical nomenclature, and so on.