Answer
a. 6.24 moles
b. 0.50 mole
c. 2.0 moles
Work Step by Step
a. Molar mass: 12.01 g/mol
$$ 75 \space g \times \frac{1 \space mole}{ 12.01 \space g} = 6.24 \space moles$$
b. Each $ C_2H_6 $ has 2 C atoms, thus:$$ 0.25 \space mole \space C_2H_6 \times \frac{ 2 \space moles \ C }{1 \space mole \space C_2H_6 } = 0.50 \space mole \space C $$
c. Molar mass: ( 12.01 $\times$ 1 )+ ( 16.00 $\times$ 2 )= 44.01 g/mol
$$ 88 \space g \times \frac{1 \space mole}{ 44.01 \space g} = 2.0 \space mole$$- Each $ CO_2 $ has 1 C atom, thus:$$ 2.0 \space moles \space CO_2 \times \frac{ 1 \space mole \ C }{1 \space mole \space CO_2 } = 2.0 \space moles \space C $$
