<span>Ammonia, NH. Hydrogen atoms can each form one covalent bond, while and nitrogen atoms can each form three covalent bonds. Three pairs of electrons are shared in an ammonia molecule (NH3).</span>
In the atom model, the poppy seeds are placed in different places to represent the different position of electrons.
<span>There are 2.74603 * 10^25 hydrogen atoms. Ammonium sulfide is represented by (NH4)2S. This means that there are 8 hydrogen atoms total. There are also 8 mol of H in ammonium sulfide. We also need to use avogadro’s number of 6.022 * 10^23.
Hydrogen Atoms = 5.7mol * (8mol / 1mol) * 6.022 * 10^23 per mol
Hydrogen atoms = 2.74603 * 10^25 hydrogen atoms.</span>
% H = 100 - ( 52.14 + 34.73 )=13.13 %
<span>assume 100 g of this compound </span>
<span>mass H = 13.13 g </span>
<span>moles H = 13.13 g / 1.008 g/mol=13 </span>
<span>mass C = 52.14 g </span>
<span>moles C = 52.14 g/ / 12.011 g/mol=4 </span>
<span>mass O = 34.73 g </span>
<span>moles O = 34.73 g/ 15.999 g/mol=2 </span>
<span>the empirical formula is C4H13O2</span>
The full question asks to decide whether the gas was a specific gas. That part is missing in your question. You need to decide whether the gas in the flask is pure helium.
To decide it you can find the molar mass of the gas in the flask, using the ideal gas equation pV = nRT, and then compare with the molar mass of the He.
From pV = nRT you can find n, after that using the mass of gass in the flask you use MM = mass/moles.
1) From pV = nRT, n = pV / RT
Data:
V = 118 ml = 0.118 liter
R = 0.082 atm*liter/mol*K
p = 768 torr * 1 atm / 760 torr = 1.0105 atm
T = 35 + 273.15 = 308.15 K
n = 1.015 atm * 0.118 liter / [ 0.082 atm*liter/K*mol * 308.15K] =0.00472 mol
mass of gas = mass of the fask with the gas - mass of the flasl evacuated = 97.171 g - 97.129 g = 0.042
=> MM = mass/n = 0.042 / 0.00472 = 8.90 g/mol
Now from a periodic table or a table you get that the molar mass of He is 4g/mol
So the numbers say that this gas is not pure helium , because its molar mass is more than double of the molar mass of helium gas.
