Mole Conversions, Percent Composition, Formula Determinations

How many moles are in 50 grams of $$NaCl$$ ? (Molar mass of $$NaCl = 58.44 \, \text{g/mol}$$ )

What is the percent composition of carbon in $$C_2H_5OH$$ ? (Molar mass of $$C = 12 \, \text{g/mol}$$ , $$H = 1 \, \text{g/mol}$$ , $$O = 16 \, \text{g/mol}$$ )

Determine the empirical formula of a compound that is 40% sulfur and 60% oxygen by mass.

A compound has an empirical formula of $$CH_2$$ and a molar mass of 56 g/mol. What is its molecular formula?

How many molecules are in 2 moles of $$CO_2$$ ?

What is the molar mass of $$CaCO_3$$ ?

Convert 10 grams of $$H_2$$ to moles. (Molar mass of $$H_2 = 2 \, \text{g/mol}$$ )

What is the percent composition of hydrogen in $$H_2O$$ ?

A compound is found to contain 85.7% carbon and 14.3% hydrogen. What is its empirical formula?

If the empirical formula of a compound is $$NH_2$$ and its molar mass is 32 g/mol, what is the molecular formula?