Question

chemistry: fundamentals and principles presented by macmillan learning consider a sample containing 0.320 mol of a substance. how many atoms are in the sample if the substance is lead? lead: atoms how many atoms are in the sample if the substance is gold? gold: atoms how many molecules are present in the sample if the substance is benzene, c₆h₆? c₆h₆: molecules

Explanation:

Step1: Recall Avogadro's number

Avogadro's number $N_A = 6.022\times 10^{23}\text{ atoms/mol}$ or $\text{molecules/mol}$.

Step2: Calculate number of atoms for lead

For lead, number of atoms $n = 0.320\text{ mol}\times N_A$.
$n = 0.320\times6.022\times 10^{23}=1.92704\times 10^{23}$ atoms.

Step3: Calculate number of atoms for gold

For gold, using the same Avogadro's number, number of atoms $n = 0.320\text{ mol}\times N_A$.
$n = 0.320\times6.022\times 10^{23}=1.92704\times 10^{23}$ atoms.

Step4: Calculate number of molecules for benzene

For benzene ($C_6H_6$), number of molecules $n = 0.320\text{ mol}\times N_A$.
$n = 0.320\times6.022\times 10^{23}=1.92704\times 10^{23}$ molecules.

Answer:

lead: $1.93\times 10^{23}$ atoms
gold: $1.93\times 10^{23}$ atoms
$C_6H_6$: $1.93\times 10^{23}$ molecules