Answer
There are $3.01 \space \times \space 10^{23} \space molecules$ in 0.500 mole of lactic acid.
Work Step by Step
1. Find the conversion factors.
Avogadro's number:
$6.022 \times 10^{23} \space molecules = 1 \space mole$
2. Calculate the number of molecules in 0.500 mole of lactic acid.
$_{0.500 \space mole \space (C_3H_6O_3)} \times \frac{6.022 \times 10^{23} \space molecules \space (C_3H_6O_3)}{1 \space mole \space (C_3H_6O_3)} = _{3.01 \times 10^{23} \space molecules \space (C_3H_6O_3)}$
