Chemical substance the mild pain-killer Naproxen is the more common name for the chemical compound (S)-6-methoxy-α-methyl-2-naphthaleneacetic acid. Chemists frequently refer to chemical compounds using chemical formulae or molecular structure of the compound. There has been a phenomenal growth in the number of chemical compounds being synthesized (or isolated), and then reported in the scientific literature by professional chemists around the world. An enormous number of chemical compounds are possible through the chemical combination of the known chemical elements. As of May 2011, about sixty million chemical compounds are known. The names of many of these compounds are often nontrivial and hence not
Prefixes in Hebrew Prefixes in Hebrew There are several prefixes in the Hebrew language which are appended to regular words to introduce a new meaning. In Hebrew, the letters that form those prefixes are called "formative letters" (Hebrew: אוֹתִיּוֹת הַשִּׁמּוּשׁ, "Otiyot HaShimush"). Eleven of the twenty-two letters of the Hebrew alphabet are considered "Otiyot HaShimush". These letters are Aleph (א), Bet (ב), He (ה), Vav (ו), Yud (י), Kaf (כ), Lamed (ל), Mem (מ), Nun (נ), Shin (ש), and Tav (ת). A mnemonic to remember these letters is איתן משה וכלב ("Eitan, Moshe, v'Kalev"), which translates to "Ethan, Moses, and Caleb." Prefixes in