Answer:
606 atoms
Explanation:
Add the numbers 145 + 293 + 168
The volume of a gas is the same as its CONTAINER.
Gases generally has no shape and no definite volume. When a gas is placed in a container, the gas usually takes the shape and the volume of the container, that is, the gas fills up all the available spaces in the container. Thus, the volume of a gas will always be the same as its container. This is in contrast with solids, which have definite shape and volume and liquids, which have definite volume but no fixed shape.
Explanation:
Contributing structures are the resonating structures which are formed due to the delocalization of electrons in a molecule.
The azide ion that is 
, is a symmetrical ion, all of whose contributing structures have formal charges.
Lone pair of central nitrogen atom in azide ion is in conjugation with the neighboring nitrogen atoms.
Contributing structures of azide ion are drawn in the image attached.
Density gives mass of object per volume...... Here, density is given 8.90 g/cm3 therefore, per cubic centimeter contains 8.90 g Ni. mole of Ni = mass / atomic mass = 8.90 / 58.6934 = 0.1516 mole number of atoms: mole * 6.022 * 10^23 = 0.1516 * 6.022 * 10^23 = 0.9129 * 10^23 = 0.9 * 10^23 (approx.)
