C)
<em>O</em><em>n</em><em>l</em><em>y</em><em> </em><em>v</em><em>a</em><em>lence</em><em> </em><em>electrons</em><em> </em><em>are involved in forming chemical bonds betwen two atoms</em><em>.</em>
Hope this helped you- have a good day bro cya)
Answer : 7.87 X

.
Explanation : To find the fraction of schottky defects in the given lattice of CsCl,
we use the formula,

on solving with the given values ,

and T as 645 + 273 K and rest are the constants.

we get the answer as 7.87 X

.
Carbon monoxide is harmful when breathed because it displaced oxygen in the blood and deprives the heart, brain, and other vital organs of oxygen.
If you search the question text (starting with "Write") you will definitely find the answer
Answer:
The correct option is;
D)
Explanation:
The given reaction is presented as follows;
NH₄Cl (s) → NH₃ (g) + HCl (g) ΔH° = 176 kJ/mol, ΔS° = 0.285 kJ/(mol·K)
We note that the Gibbs free energy, ΔG° is represented by the following equation;
ΔG° = ΔH° - T·ΔS°
Where:
T = Temperature (Kelvin)
The reaction will be spontaneous for exergonic reactions, ΔG° < 0 and it will not be spontaneous for endergonic reaction, ΔG° > 0
At room temperature, T = 25 + 273.15 = 298.15 K
Which gives;
ΔG° = 176 - 298.15 × 0.285 = 91.03 kJ/mol which is > 0 Not spontaneous reaction
At 800°C, we have;
T = 273.15 + 800°C + 1073.15 K
ΔG° = 176 - 1073.15 * 0.285 = -129.85 kJ/mol which is < 0 the reaction will be spontaneous
The correct option is therefore, that at room temperature, the reaction is not spontaneous. However, at high temperatures. like 800 °C, the free energy value turns negative and this reaction becomes spontaneous.