Question

1. how many molecules of sulfur tetrafluoride are present in 4.82 grams of this compound? 2. how many grams of sulfur tetrafluoride are present in 4.47×10²² molecules of this compound? use the references to access important values if needed for this question. 9 more group attempts remaining

Explanation:

Step1: Calculate molar mass of sulfur tetrafluoride ($SF_4$)

The molar mass of $S$ is approximately $32.07\ g/mol$ and of $F$ is approximately $19.00\ g/mol$. For $SF_4$, molar mass $M = 32.07+4\times19.00=32.07 + 76.00=108.07\ g/mol$.

Step2: Solve for number of moles in 4.82 grams of $SF_4$

Use the formula $n=\frac{m}{M}$, where $m = 4.82\ g$ and $M = 108.07\ g/mol$. So $n=\frac{4.82}{108.07}\ mol$.

Step3: Calculate number of molecules

Use Avogadro's number $N_A=6.022\times 10^{23}\ molecules/mol$. The number of molecules $N=n\times N_A=\frac{4.82}{108.07}\times6.022\times 10^{23}\ molecules$.
$N=\frac{4.82\times6.022\times 10^{23}}{108.07}\approx2.69\times 10^{22}\ molecules$.

Step4: Solve for mass in $4.47\times 10^{22}$ molecules of $SF_4$

First find the number of moles $n=\frac{N}{N_A}=\frac{4.47\times 10^{22}}{6.022\times 10^{23}}\ mol$. Then use $m = n\times M$.
$n=\frac{4.47\times 10^{22}}{6.022\times 10^{23}}\approx0.0742\ mol$.
$m=n\times M=0.0742\times108.07\ g\approx8.02\ g$.

Answer:

1. $2.69\times 10^{22}$ molecules
2. $8.02$ grams