Answer: Option (d) is the correct answer.
Explanation:
In solids, molecules are held together by strong intermolecular forces of attraction. As a result, they are unable to move from their initial position and can only vibrate at their mean position.
Hence, a solid has definite shape and volume. Solids cannot be compressed.
Whereas in plasma, molecules are hot ionized which include positively charged ions and negatively charged electrons. They collide much more rapidly with each other and are widely spreaded out.
Therefore, they occupy the volume of container in which they are placed. Plasma can be compressed.
Thus, we can conclude that substance X is a solid and substance Y is a plasma.
When a material is heated, the kinetic energy of that material increases and its atoms and molecules move about more. This means that each atom will take up more space due to its movement so the material will expand. ... Some metals expand more than others due to differences in the forces between the atoms / molecules.
Answer:
ZnS
Explanation:
1. Number of Zn atoms
4 internal atoms = 4 Zn atoms
2. Number of S atoms
8 corners × ⅛ S atom/corner + 6 faces × ½ S atom/face = 1 S atom + 3 S atoms = 4 S atoms
3. Empirical formula
The atomic ratio is
4Zn:4S = 1Zn:1S
The empirical formula is ZnS.
Answer:
The correct answer is "Iron and oxygen act as Fe3+ and O2− ions respectively, forming rust (Fe₂O₃) in the presence of water by the formation of an ionic bond".
Explanation:
Rust is formed when iron reacts with oxygen in the presence of water (either if the iron is submerged or exposed to moisture in the air), forming the chemical compound Fe₂O₃. The presence of water is needed for rust formation because iron and oxygen act as ions when they are exposed to water, particularly Fe3+ and O2− ions respectively. The bond formed between these two elements are ionic bonds, because it is comprised of the reaction between a metal (iron) and a non-metal (oxygen).
Answer:
The density of Lithium β is 0.5798 g/cm³
Explanation:
For a face centered cubic (FCC) structure, there are total number of 4 atoms in the unit cell.
we need to calculate the mass of these atoms because density is mass per unit volume.
Atomic mass of Lithium is 6.94 g/mol
Then we calculate the mass of four atoms;
⇒next, we estimate the volume of the unit cell in cubic centimeter
given the edge length or lattice constant a = 0.43nm
a = 0.43nm = 0.43 X 10⁻⁹ m = 0.43 X 10⁻⁹ X 10² cm = 4.3 X 10⁻⁸cm
Volume of the unit cell = a³ = (4.3 X 10⁻⁸cm)³ = 7.9507 X 10⁻²³ cm³
⇒Finally, we calculate the density of Lithium β
Density = mass/volume
Density = (4.6097 X 10⁻²³ g)/(7.9507 X 10⁻²³ cm³)
Density = 0.5798 g/cm³
