Grams to Molecules

Convert 8.30 x 10$^{24}$ atoms to moles of atoms. Use dimensional analysis and show how the units cancel to give the correct answer.

Convert 5 moles of carbon to grams.

A sample of 45.8 g of MgSO$_4$ $\cdot$ 4 H$_2$O contains how many moles of MgSO$_4$ $\cdot$ 4 H$_2$O ?

How many moles of sodium ions, Na$^{+}$, are there in 5.63 g of Na$_2$SO$_4$ ? (molar mass of Na$_2$SO$_4$ = 124.04 g/mol)