## Chemistry: Atoms First (2nd Edition)

a. 619 g of $P$ b. 310. g of $P$ c. 155 g of $P$
a. - Each $P_4O_6$ has 4 P atoms, thus:$$5.00 \space mole \space P_4O_6 \times \frac{ 4 \space moles \ P }{1 \space mole \space P_4O_6 } = 20.0 \space moles \space P$$ - Calculate or find the molar mass for $P$: $P$ : 30.97 g/mol - Using the molar mass as a conversion factor, find the mass in g: $$20.0 \space mole \times \frac{ 30.97 \space g}{1 \space mole} = 619 \space g$$ b. - Each $Ca_3(PO_4)_2$ has 2 P atoms, thus:$$5.00 \space mole \space Ca_3(PO_4)_2 \times \frac{ 2 \space moles \ P }{1 \space mole \space Ca_3(PO_4)_2 } = 10.0 \space moles \space P$$ - Using the molar mass as a conversion factor, find the mass in g: $$10.0 \space mole \times \frac{ 30.97 \space g}{1 \space mole} = 310. \space g$$ c,- Each $Na_2HPO_4$ has 1 P atoms, thus:$$5.00 \space mole \space Na_2HPO_4 \times \frac{ 1 \space moles \ P }{1 \space mole \space Na_2HPO_4 } = 5.00 \space moles \space P$$ $$5.00 \space mole \times \frac{ 30.97 \space g}{1 \space mole} = 155 \space g$$