Question

Give the composition of pyrex glass. Give its uses.

Short answer

Answer: Pyrex glass is a type of borosilicate glass composed of approximately 80% silica, 13% boric oxide, 4% alumina, and 3% from alkali and alkaline earth oxides. It has a low coefficient of thermal expansion and good chemical resistance. Common uses of Pyrex glass include laboratory glassware, kitchenware, telescope mirrors, microwave components, and high-intensity lighting applications.

Step-by-step solution

Composition of Pyrex Glass

Pyrex glass is a type of borosilicate glass which is composed of silica (SiO₂), boric oxide (B₂O₃), alumina (Al₂O₃), and smaller amounts of alkali and alkaline earth oxides like sodium oxide (Na₂O) and calcium oxide (CaO). The approximate composition is 80% silica, 13% boric oxide, 4% alumina, and the remaining 3% from alkali and alkaline earth oxides.

Properties of Pyrex Glass

The unique combination of materials in Pyrex glass gives it a set of useful properties. It has a low coefficient of thermal expansion, making it resistant to thermal shock. This means that it can be used in various temperature environments without cracking or shattering due to rapid temperature changes. It also has good chemical resistance, making it suitable for laboratory glassware and certain kitchenware.

Uses of Pyrex Glass

Some common uses of Pyrex glass include: 1. Laboratory glassware: Due to its thermal and chemical resistance, Pyrex glass is widely used for laboratory equipment such as beakers, flasks, and test tubes. 2. Kitchenware: Oven-safe glassware like casserole dishes, measuring cups, and baking dishes are often made from Pyrex glass due to its ability to withstand high temperatures and resist breaking when heated or cooled quickly. 3. Telescope mirrors: Pyrex glass is used for telescope mirrors because of its low coefficient of thermal expansion, which ensures that the mirror's shape remains stable as temperatures change, resulting in more accurate observations. 4. Microwave components: Some microwave components, such as waveguide windows, are made of Pyrex glass due to its combination of low electrical conductivity and excellent transparency to microwave radiation. 5. Lighting: Pyrex glass is used for high-intensity lighting applications, such as those found in scientific and industrial settings, because it can withstand the high temperatures generated by these light sources without warping or degrading.