Ca(OH)2 -------> CaO + H2O
ratio is 1 : 1
CaO Mr= 56g
15/56 = 0.268 mol (mols of CaO in 15g)
Ca(OH)2 Mr= 74g
0.268x74= 19.83g (required amount of Cash(OH)2)
Answer:
option b is correct
Explanation:
Taking the Van't Hoff equation
d ln Keq / dT = ΔH/(RT²)
then
Keq increases with increasing temperature (d ln Keq / dT>0) when ΔH>0 and decreases with increasing temperature (d ln Keq / dT<0) when ΔH<0
if Keq decreases (reactions shift toward reactants) from 7.9×10³ to 0.77 when temperature increases from 298 K to 713 K (d ln Keq / dT<0) → ΔH<0 ( exothermic reaction)
therefore option b is correct
Ionic compound is formed by negative and positive ions, these ions form ionic bond
A column of elements is a period