Unless you live in a moist climate, powdered sugar should last "forever". If it looks icky, though, don't use it. (ie, clumped together, any color besides white.) Otherwise, it should be okay.
Yes it does the powdered sugar does grow faster and the granulated sugar starts to mold
When substituting powdered sugar for granulated sugar, the general ratio is 1:1. However, since powdered sugar is finer and contains a small amount of cornstarch, it may slightly alter the texture of baked goods. For most recipes, you can use the same amount of powdered sugar as granulated sugar, but keep in mind that the sweetness level may be perceived as slightly different.
powdered sugar = Puderzucker
There is no "cake powdered sugar". Powdered sugar is made from sugar, which is ground into a powdered form, with a minute amount of corn starch added to prevent it from "caking" or lumping.
potassium permanganate reacts with powdered sugar
Powdered sugar is not the same as regular sugar. Regular sugar is granulated, while powdered sugar is finely ground and mixed with a small amount of cornstarch.
Sugar beets can be turned into granulated sugar
Yes, you can substitute confectioners' sugar for powdered sugar in this recipe.
Powdered sugar crystal
I wasn't aware that it did, but it would be there to keep it a powder. The cornstarch would coat the sugar crystals and keep them from sticking together.
it doesn't really matter as long as you put the powdered sugar in last.
No, powdered sugar does not contain gluten as it is made from refined sugar and cornstarch, which are gluten-free ingredients.