How many iron atoms are present in a stainless steel ball bearing has a radius of $0.1 \mathrm{inch}$ $\left(1 \mathrm{inch}=2.54 \mathrm{cm}\right)$? The stainless steel contains $85.6\%$ $\mathrm{Fe}$ by weight and has a density of $7.75 \mathrm{g} {\mathrm{cc}}^{-1}$. $(\mathrm{If} \mathrm{answer} \mathrm{is} \mathrm{x} \times {10}^{21}. \mathrm{Then} \mathrm{value} \mathrm{of} \mathrm{x} \mathrm{is})$

How many litres of liquid ${\mathrm{CCl}}_{4 }\left(\mathrm{d}=1.5 \mathrm{g} {\mathrm{cc}}^{-1}\right)$ must be measured out to contain $1\times {10}^{25} {\mathrm{CCl}}_4$ molecules?

(Calculate the volume in litres)

A sample of potato starch was ground in a ball mill to give a starch-like molecule of lower molecular weight. The product analysed $0.086\%$ Phosphorus. If each molecule is assumed to contain one atom of phosphorus, what is the molecular weight of the material? 

The molecular weight of the material is $\mathrm{z}\times {10}^3 \mathrm{g}$, find $\mathrm{z}$(Nearest integer).

To what volume in $\mathrm{mL}$, must $50 \mathrm{mL}$ of $3.50 \mathrm{M} {\mathrm{H}}_2{\mathrm{SO}}_4$ be diluted in order to make $2 \mathrm{M}$ ${\mathrm{H}}_2{\mathrm{SO}}_4$?

Calculate the volume in $\mathrm{mL}$.

Sulphur molecules exist under various conditions as ${\mathrm{S}}_8,{\mathrm{S}}_6,{\mathrm{S}}_4,{\mathrm{S}}_2$ and $\mathrm{S}$.

(a) Is the mass of one mole of each of these molecules the same?

(b) Is the number of molecules in one mole of each of these molecules the same?

(c) Is the mass of sulphur in one mole of each of these molecules the same?

(d) Is the number of atoms of sulphur in one mole of each of these molecules the same?

Two minerals that contain $\mathrm{Cu}$ are ${\mathrm{CuFeS}}_2$ and ${\mathrm{Cu}}_2\mathrm{S}$. What mass in $\mathrm{lb}$ of ${\mathrm{Cu}}_2\mathrm{S}$ would contain the same mass of $\mathrm{Cu}$ as is contained in $125 \mathrm{lb}$ of ${\mathrm{CuFeS}}_2$?

Round off your answer to the nearest integer.