<span>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</span>
Answer:
Explanation:
Percent composition is percentage by the mass of element present in the compound.
The formula for chromium(III) nitrate is 
Molar mass of chromium(III) nitrate = 238.011 g/mol
1 mole of chromium(III) nitrate contains 9 moles of oxygen
Molar mass of oxygen = 16 g/mol
So, Mass= Molar mass*Moles = 16*9 g = 144 g
2AgNO3+K2CrO4⇒Ag2CrO4(s)+2KNO3
Hence by mixing 0.0024M AgNO3 and 0.004M
K2CrO4, we will have Ag2CrO4 which is precipitated out and leave us with
0.0024M KN03 which is mixed with (0.004-0.0024/2)M, it can be 0.0028M, of K2Cr04
Answer:- selenium, Se.
Explanations:- When an element gain electrons then it becomes negatively charged means it forms it's anion. Total electrons of the anion are the sum of electrons and the charge of the anion. In our problem, the element is q and it forms 
ion. The Total electrons for the anion = electrons of q + 2
As per the given info, there are 36 electrons in ion.
So, 36 = electrons of q + 2
electrons of q = 36 - 2
electrons of q = 34
q, the neutral atom has 34 electrons means it's atomic number is 34. If we check out the periodic table then the element with atomic number 34 is Selenium, Se.
Since there are no choices given, my answer might not be what you're looking for. But it can definitely be a correct answer. The technique is called filtration. Filtration is a physical separation to separate the liquid and solid in a mixture. The mixture should be composed of an insoluble solid in a solvent. The mixture is usually passed through a semi-permeable barrier. In this case, a special piece of paper is used. The solvent is the liquid and the solid is the coffee bean grounds. Only the liquid can pass through the paper. The liquid that passes through the paper is generally called a filtrate.
