Objects made of this material are engraved with the overlaid letters S and T to indicate a “standard taper.” Silanization makes this material inert by reacting away its surface hydroxyl groups. Chromic acid removes organic residue stuck to this material. Keck clips attach pieces of this material at greased joints where it is ground smooth—for instance, between a Vigreux (“VIG-roo”) distillation column and its (*) condenser. Impregnating this material with boron trioxide improves (10[1])its thermal stability. (0[1])Rubber bulbs are attached to Pasteur pipettes made out of this material, which is often preferred to plastic when working with strong acids and bases. For 10 points, Erlenmeyer flasks and beakers (10[1])are made out of what fragile material? ■END■