Which combination would act as an acidic buffer? A.
HCl and NaOH
B.
CH3COOH and NaCH3COO
C.
HNO2 and HF
D.
NH3 and NH4Cl
E.
HCl and KCl

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

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

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.