Find Molar Mass

What is the molar mass of NaCl $\cdot$ 2 H$_2$O ?

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.

Convert 15 grams of CO$_2$ to moles of CO$_2$