Chemical substance In organic chemistry, there can be more than one chemical compound with the same composition and molecular weight. Generally, these are called isomers. Isomers usually have substantially different chemical properties, and often may be isolated without spontaneously interconverting. A common example is glucose vs. fructose. The former is an aldehyde, the latter is a ketone. Their interconversion requires either enzymatic or acid-base catalysis. However, tautomers are an exception: the isomerization occurs spontaneously in ordinary conditions, such that a pure substance cannot be isolated into its tautomers, even if these can be identified spectroscopically or even isolated in special conditions. A
Magic Tree House Magic Tree House Merlin Mission Books 1-27 were written for more advanced readers. They are more challenging adventures for readers ages 7–10. The Magic Tree House Merlin Missions were originally ordered sequentially, starting at Book #29 (Christmas in Camelot). With the 25th anniversary re-prints, the books have been separated into their own distinct series and re-numbered starting at Merlin Mission #1. On January 6, 2015, the first Magic Tree House Super Edition was released. It is 183 pages long. The super editions are longer than the original Magic Tree House books and the Magic Tree House Merlin Missions. The Magic