How many elements are in oxygen

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 number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

Which element has the lowest electronegativity? calcium(ca) gallium(ga) selenium(se) bromine(br)