The number of molecules of $CO_2$ present in $44 \ g$ of $CO_2$ is

Consider two sealed jars of equal volume. One contains $2 \ g$ of hydrogen at $200 \ K$ and the other contains $28 \ g$ of nitrogen at $400 \ K$. The gases in the two jars will have

Calculate the following for $3 \ mol$ of ethane $(C_2H_6)$:
$(i)$ Number of moles of carbon atoms
$(ii)$ Number of moles of hydrogen atoms
$(iii)$ Number of molecules of ethane

Calculate the number of $Ca^{2+}$ ions in $222 \ g$ of anhydrous calcium chloride $(CaCl_2)$? (Atomic mass: $Ca = 40 \ u$,$Cl = 35.5 \ u$)

The number of molecules in $16 \ g$ of methane is

What is the weight in $g$ of $2.01 \times 10^{23}$ molecules of $CO$?