Answer:
1.72x10⁻⁵ g
Explanation:
To solve this problem we use the PV=nRT equation, where:
- R = 0.082 atm·L·mol⁻¹·K⁻¹
- T = 25 °C ⇒ (25+273.16) = 298.16 K
And we <u>solve for n</u>:
- 1 atm * 5.7x10⁶ L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 298.16 K
Finally we <u>convert moles of helium to grams</u>, using its <em>molar mass</em>:
- 4.29x10⁻⁶ mol * 4 g/mol = 1.72x10⁻⁵ g
What age group typically uses inhalants? I hope that’s a good one
Bismuth-209 (209Bi) is the isotope of bismuth with the longest known half-life of any radioisotope that undergoes α-decay (alpha decay). It has 83 protons and a magic number of 126 neutrons, and an atomic mass of 208.9803987 amu (atomic mass units). Of the first 82 elements in the periodic table, 80 have isotopes considered to be stable.[1] The 83rd element, bismuth, was traditionally regarded as having the heaviest stable isotope, bismuth-209, but in 2003 researchers in Orsay, France, measured the half-life of 209
Bi
to be 1.9×1019 years.[2][3] Technetium and promethium (atomic numbers 43 and 61, respectively[a]) and all the elements with an atomic number over 82 only have isotopes that are known to decompose through radioactive decay. No undiscovered elements are expected to be stable; therefore, lead is considered the heaviest stable element. However, it is possible that some isotopes that are now considered stable will be revealed to decay with extremely long half-lives (as with 209
Bi
). This list depicts what is agreed upon by the consensus of the scientific community as of 2019.
Explanation:
It is known that density is mass of a substance divided by its volume.
Mathematically, Density =
Therefore, calculate the mass of cyclohexane as follows.
mass of cyclohexane = Density × volume
=
= 15.58 g
or, = 0.01558 kg (as 1 kg = 1000 g)
As, K_{f} of cyclohexane =
molality =
= 0.26 m
Also, molality is the number of moles of solute present in kg of solvent.
Mathematically, molality =
0.26 =
No. of moles =
As, No. of moles =
molar mass = 87.0 g/mol
Thus, we can conclude that molar mass of unknown substance is 87.0 g/mole.