NaClO₃ is used, even in spacecrafts, to produce O₂. The daily consumption of pure O₂ by a person is 492L at 1 atm, 300K. How much amount of NaClO₃, in grams, is required to produce O₂ for the daily consumption of a person at 1 atm, 300 K?
NaClO₃(s) + Fe(s) $$ \to $$ O₂(g) + NaCl(s) + FeO(s)
R = 0.082 L atm mol^–1 K^–1

At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The molar heat capacity at constant volume is _______.

Complexes (ML₅) of metals Ni and Fe have ideal square pyramidal and trigonal bipyramidal grometries, respectively. The sum of the 90°, 120° and 180° L-M-L angles in the two complexes is ________.

Let $$\overrightarrow a = \widehat i - 2\widehat j + \widehat k$$ and $$\overrightarrow b = \widehat i - \widehat j + \widehat k$$ be two vectors. If $$\overrightarrow c $$ is a vector such that $$\overrightarrow b \times \overrightarrow c = \overrightarrow b \times \overrightarrow a $$ and $$\overrightarrow c .\overrightarrow a = 0$$, then $$\overrightarrow c .\overrightarrow b $$ is equal to