Iron oxide $FeO$, crystallises in a cubic lattice with a unit cell edge length of $50 \mathring{A}$ If density of the $FeO$ in the crystal is $40\, g \,cm ^{-3}$, then the number of $FeO$ units present per unit cell is ______ (Nearest integer) Given: Molar mass of $Fe$ and $O$ is $56$ and $16 \, g \, mol ^{-1}$ respectively $N _{ A }=60 \times 10^{23} mol ^{-1}$
Correct Answer: 4
Solution and Explanation
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\(2Fe^{3+}+2I^{-}_{(aq)}\rightarrow2Fe^{2+}+I_2{(aq)}\)
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Concepts Used:
Solid State
Solids are substances that are featured by a definite shape, volume, and high density. In the solid-state, the composed particles are arranged in several manners. Solid-state, in simple terms, means "no moving parts." Thus solid-state electronic devices are the ones inclusive of solid components that don’t change their position. Solid is a state of matter where the composed particles are arranged close to each other. The composed particles can be either atoms, molecules, or ions.
Types of Solids:
Based on the nature of the order that is present in the arrangement of their constituent particles solids can be divided into two types;
- Amorphous solids behave the same as super cool liquids due to the arrangement of constituent particles in short-range order. They are isotropic and have a broad melting point (range is about greater than 5°C).
- Crystalline solids have a fixed shape and the constituent particles are arranged in a long-range order.