<span>9.40x10^19 molecules.
The balanced equation for ammonia is:
N2 + 3H2 ==> 2NH3
So for every 3 moles of hydrogen gas, 2 moles of ammonia is produced. So let's calculate the molar mass of hydrogen and ammonia, starting with the respective atomic weights:
Atomic weight nitrogen = 14.0067
Atomic weight hydrogen = 1.00794
Molar mass H2 = 2 * 1.00794 = 2.01588 g/mol
Molar mass NH3 = 14.0067 + 3 * 1.00794 = 17.03052 g/mol
Moles H2 = 4.72 x 10^-4 g / 2.01588 g/mol = 2.34140921086573x10^-4 mol
Moles NH3 = 2.34140921086573x10^-4 mol * (2/3) = 1.56094x10^-4 mol
Now to convert from moles to molecules, just multiply by Avogadro's number:
1.56094x10^-4 * 6.0221409x10^23 = 9.400197448261x10^19
Rounding to 3 significant figures gives 9.40x10^19 molecules.</span>
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The answer to your question would be D Volumetric Flask
The best and most correct answer among the choices provided by your question is the second choice or letter B.
<span>The most accurate measurement based on the limitations of the balance that might be found in her recorded data would be 9.2</span>
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
<span>we are going to use H-H equation:
PH = Pka + log[conjugate base]/[weak acid]
when we have here the conjugate base is NaF
and the weak acid is HF.
so, we are going to use the Ka value to get the value of Pka.
when Pka = -logKa
= -log7.2 X 10^-4
= 3.14
then we will substitution on H-H equation:
</span>∴<span>PH = 3.14 + log (0.623)/(1.41) = 2.99</span>
