The empirical formula is a formula of a compound showing the proportion of each element involved in the compounds but it does not represent the total number of atoms in the compound. It is the lowest number of ratio between the elements in the compound. In order, to determine the actual number of the atoms or the molecular formula of the compounds, we make use of the molar mass of the compound.
<span>To
determine the molecular formula, we multiply a value to the empirical formula.
Then, calculate the molar mass and see whether it is equal to the one
given (104.1 g/ mol). From the choices, the only valid options are b, d and e.
</span> molar mass
1 CH 13.02
8 C8H8 104.16
6 C6H6 78.12
Therefore the correct answer is option B.
a. pH=2.07
b. pH=3
c. pH=8
<h3>Further explanation</h3>
pH=-log [H⁺]
a) 0.1 M HF Ka = 7.2 x 10⁻⁴
HF= weak acid
![\tt [H^+]=\sqrt{Ka.M}\\\\(H^+]=\sqrt{7.2.10^{-4}\times 0.1}\\\\(H^+]=8.5\times 10^{-3}\\\\pH=3-log~8.5=2.07](https://tex.z-dn.net/?f=%5Ctt%20%5BH%5E%2B%5D%3D%5Csqrt%7BKa.M%7D%5C%5C%5C%5C%28H%5E%2B%5D%3D%5Csqrt%7B7.2.10%5E%7B-4%7D%5Ctimes%200.1%7D%5C%5C%5C%5C%28H%5E%2B%5D%3D8.5%5Ctimes%2010%5E%7B-3%7D%5C%5C%5C%5CpH%3D3-log~8.5%3D2.07)
b) 1 x 10⁻³ M HNO₃
HNO₃ = strong acid
![\tt pH=-log[1\times 10^{-3}]=3](https://tex.z-dn.net/?f=%5Ctt%20pH%3D-log%5B1%5Ctimes%2010%5E%7B-3%7D%5D%3D3)
c) 1 x 10⁻⁸ M HCl
![\tt pH=-log[1\times 10^{-8}]=8](https://tex.z-dn.net/?f=%5Ctt%20pH%3D-log%5B1%5Ctimes%2010%5E%7B-8%7D%5D%3D8)
elements have equal number of protons and neutrons
the condensed format is when the closest noble gas with the closest electron configuration is given, this closest noble gas atomic number should be lesser than the atoms atomic number
atomic number of Kr is 36
1 electron in 5s subshell and 7 electrons in 4d subshell.
there's a total of 36 + 1 + 7 = 44 electrons
atomic number of the atom is 44
element with atomic number 44 is Ruthenium - Ru
answer is Ru
<span>lithium and fluoride ions are arranged in an alternating three-dimensional crystal lattice. It's not possible to really isolate a single Li-F pair in the solid state. The many positive-negative electrical attractions hold the solid together. Ionic compounds are usually solids at room temperature since these electrical attractions are quite strong.</span>
