how many formula units (ionicmolecules) of mercury(i) perchlorate, hg₂(clo₄)₂, are in 1.24 g of mercury(i)…

how many formula units (ionicmolecules) of mercury(i) perchlorate, hg₂(clo₄)₂, are in 1.24 g of mercury(i) perchlorate? report your answer in proper scientific notation to the correct number of sig figs by filling in the following blanks, but do not include units in your answer.\n\nquestion 8\n1 pts\nhow many milligrams are present in 6.24×10¹⁹ molecules of fecl₃? report your answer to the correct number of significant figures and rounding with the units reported in the second box.\n\nquestion 9\n1 pts\ncalculate the mass (in ng) of 6.29×10¹³ molecules of oxygen, o₂. report your answer to 2 decimal places, but do not report the units.

how many formula units (ionicmolecules) of mercury(i) perchlorate, hg₂(clo₄)₂, are in 1.24 g of mercury(i) perchlorate? report your answer in proper scientific notation to the correct number of sig figs by filling in the following blanks, but do not include units in your answer.\n\nquestion 8\n1 pts\nhow many milligrams are present in 6.24×10¹⁹ molecules of fecl₃? report your answer to the correct number of significant figures and rounding with the units reported in the second box.\n\nquestion 9\n1 pts\ncalculate the mass (in ng) of 6.29×10¹³ molecules of oxygen, o₂. report your answer to 2 decimal places, but do not report the units.

Answer

Question 7

Explanation:

Step1: Calculate molar mass of $Hg_2(ClO_4)_2$

The molar mass of Hg is 200.59 g/mol, Cl is 35.45 g/mol, and O is 16.00 g/mol. $M = 2\times200.59+2\times35.45 + 8\times16.00=401.18 + 70.9+128.0 = 600.08$ g/mol

Step2: Calculate number of moles

$n=\frac{m}{M}$, where $m = 1.24$ g and $M=600.08$ g/mol. $n=\frac{1.24}{600.08}\approx2.07\times 10^{-3}$ mol

Step3: Calculate formula - units

Use Avogadro's number $N_A = 6.022\times 10^{23}$ formula - units/mol. $N=n\times N_A=2.07\times 10^{-3}\times6.022\times 10^{23}=1.25\times 10^{21}$

Answer:

$1.25$ $21$

Question 8

Explanation:

Step1: Calculate molar mass of $FeCl_3$

The molar mass of Fe is 55.85 g/mol and Cl is 35.45 g/mol. $M = 55.85+3\times35.45=55.85 + 106.35=162.2$ g/mol

Step2: Calculate number of moles

$n=\frac{N}{N_A}$, where $N = 6.24\times 10^{19}$ molecules and $N_A=6.022\times 10^{23}$ molecules/mol. $n=\frac{6.24\times 10^{19}}{6.022\times 10^{23}}\approx1.04\times 10^{-4}$ mol

Step3: Calculate mass in grams

$m=n\times M$, so $m = 1.04\times 10^{-4}\times162.2 = 0.0168688$ g

Step4: Convert to milligrams

$m = 0.0168688\times1000 = 16.9$ mg

Answer:

$16.9$ mg

Question 9

Explanation:

Step1: Calculate molar mass of $O_2$

The molar mass of O is 16.00 g/mol, so for $O_2$, $M = 2\times16.00 = 32.00$ g/mol

Step2: Calculate number of moles

$n=\frac{N}{N_A}$, where $N = 6.29\times 10^{13}$ molecules and $N_A = 6.022\times 10^{23}$ molecules/mol. $n=\frac{6.29\times 10^{13}}{6.022\times 10^{23}}\approx1.04\times 10^{-10}$ mol

Step3: Calculate mass in grams

$m=n\times M$, so $m=1.04\times 10^{-10}\times32.00 = 3.328\times 10^{-9}$ g

Step4: Convert to nanograms

Since 1 g = $10^{9}$ ng, $m = 3.33$ ng

Answer:

$3.33$