Aradioactive nuclide that is used for geological dating has an atomic number of 19 and mass number 40. which is the symbol of this nuclide?

Ahypothrticalax type of ceramic material is known to have a density of 2.10 g/cm3 and a unit cell of cubic symmetry with a cell edge length of 0.57 nm. the atomic weights of the a and x elements are 28.5and 30.0 g/mol, respectively. on the basis of this information, which of the following crystal structures is (are) possible for this material: sodium chloride, cesium chloride, or zinc blende

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

All cells are made of four types of acids, lipids, proteins, and carbohydrates.