# Calculate the amount of (mol) of Rh in 1.69g of Rh. If the molar mass is 102.90?

You have 0.01642 moles of rhodium, $\text{Rh}$, in $\text{1.69 g}$ of $\text{Rh}$.
You know that $\text{Rh}$'s molar mass is $\text{102.90 g/mol}$. What that means is that 1 mole of rhodium weighs $\text{102. 9 g}$. If you compare that to 1.69 g, the mass given to you, it'll be obvious that you have less than 1 mole.
$\text{1.69 g Rh" * "1 mole"/"102.9 g" = "0.01642 moles Rh}$