The minimum number of moles of O₂ required for complete combustion of 1 mole of propane and 2 moles of butane is _____.

The potential energy curve for the H₂ molecule as a function of internuclear distance is :

In the sixth period, the orbitals that are filled are :

If $$\alpha $$ is positive root of the equation, p(x) = x² - x - 2 = 0, then

$$\mathop {\lim }\limits_{x \to {\alpha ^ + }} {{\sqrt {1 - \cos \left( {p\left( x \right)} \right)} } \over {x + \alpha - 4}}$$ is equal to :