The symbols of calcium,carbon,and copper are

$(a)$ In this crossword puzzle (Fig),names of $11$ elements are hidden. Symbols of these are given below. Complete the puzzle.
$1. Cl$
$2. H$
$3. Ar$
$4. O$
$5. Xe$
$6. N$
$7. He$
$8. F$
$9. Kr$
$10. Rn$
$11. Ne$
$(b)$ Identify the total number of inert gases,their names,and symbols from this crossword puzzle.

Calculate the mass of:
$(a)$ $1$ atom of carbon
$(b)$ $0.02$ mole of sodium
$(c)$ $1$ molecule of water.

In photosynthesis,$6$ molecules of carbon dioxide combine with an equal number of water molecules through a complex series of reactions to give a molecule of glucose having a molecular formula $C_6H_{12}O_6$. How many grams of water would be required to produce $18\, g$ of glucose? Compute the volume of water (in $cm^3$) so consumed assuming the density of water to be $1\, g\, cm^{-3}$.

The unit accepted for measuring the mass of an atom and a molecule is

You are provided with a fine white-coloured powder which is either sugar or salt. How would you identify it without tasting?