How many moles are represented by $100 \mathrm{g}$ of glucose, ${\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6$? $(\mathrm{C}=12 \mathrm{u}, \mathrm{H}= 1 \mathrm{u}, \mathrm{O}=16 \mathrm{u})$

Calculate the mass in grams of $0.17$ mole of hydrogen sulphide, ${\mathrm{H}}_2\mathrm{S}$. (Atomic masses : $\mathrm{H}=1 \mathrm{u}, \mathrm{S}=32 \mathrm{u}$) 

Calculate the mole ratio of $240 \mathrm{g}$ of calcium and $240 \mathrm{g}$ of magnesium. $(\mathrm{Ca}=40 \mathrm{u} ; \mathrm{Mg}=24 \mathrm{u})$ 

What weight of each element is present in $1.5$ moles of sodium sulphite. ${\mathrm{Na}}_2{\mathrm{SO}}_3$? (Atomic masses: $\mathrm{Na}=23\mathrm{u}; \mathrm{S}=32; \mathrm{O}=16\mathrm{u}$). 

Which has more atoms, $50$ g of aluminium or $50$ g of iron? Illustrate your answer with the help of calculations. (Atomic masses: $\mathrm{Al}=27\mathrm{u}; \mathrm{Fe}=56\mathrm{u}$).