Respuesta :
15.4 milligrams
The ideal gas law is
PV = nRT
where
P = pressure of the gas
V = volume of the gas
n = number of moles of gas
R = Ideal gas constant (8.3144598 L*kPa/(K*mol) )
T = absolute temperature.
So let's determine how many moles of gas has been collected.
Converting temperature from C to K
273.15 + 25 = 298.15 K
Converting pressure from mmHg to kPa
753 mmHg * 0.133322387415 kPa/mmHg = 100.3917577 kPa
Taking idea gas equation and solving for n
PV = nRT
PV/RT = n
n = PV/RT
Substituting known values
n = PV/RT
n = (100.3917577 kPa 0.195 L) / (8.3144598 L*kPa/(K*mol) 298.15 K)
n = (19.57639275 L*kPa) / (2478.956189 L*kPa/(mol) )
n = 0.007897031 mol
So we have a total of 0.007897031 moles of gas particles.
Now let's get rid of that percentage that's water vapor. The percentage of water vapor is the vapor pressure of water divided by the total pressure. So
24/753 = 0.03187251
The portion of hydrogen is 1 minus the portion of water vapor. So
1 - 0.03187251 = 0.96812749
So the number of moles of hydrogen is
0.96812749 * 0.007897031 mol = 0.007645332 mol
Now just multiple the number of moles by the molar mass of hydrogen gas. Start with the atomic weight.
Atomic weight hydrogen = 1.00794
Molar mass H2 = 1.00794 * 2 = 2.01588 g/mol
Mass H2 = 2.01588 g/mol * 0.007645332 mol = 0.015412073 g
Rounding to 3 significant figures gives 0.0154 g = 15.4 mg
Answer:- 0.0153 grams
Explanation:- According to Dalton's law, the total pressure is the sum of individual pressures.
[tex]p_{total}=p_{H_2O}+p{H_2}[/tex]
[tex]p753mmHg=24mmHg+p{H_2}[/tex]
[tex]p_{H_2}=729mmHg[/tex]
According to the ideal gas equation:'
[tex]PV=nRT[/tex]
Pressure of the gas = 729 mmHg = 0.96 atm (1mmHg=0.0013atm)
Volume of the gas = 195 mL = 0.195 L
Temperature of the gas = 25°C =(25+273)= 295K (0°C = 273 K)
R= gas constant = 0.0821Latm\Kmol
[tex]n=\frac{PV}{RT}=\frac{0.96\times 0.195 }{0.0821 \times 298 K}=7.65\times 10^{-3}mol[/tex]
Mass of [tex]H_2=moles\times {\text {Molar mass}}=7.65\times 10^{-3}\times 2=0.0153g[/tex]
