The pH is calculated using the expression: pH = - log [H3O+].
To find the concentration of [H3O+]
[H3O+] = 10^(-pH)
Solving the RHS we have 10^(-4.240) = 0.1440
Hence the concentration of H3O+ is 0.1440.
The correct answer would be 2
We calculate the molar concentration [Cl⁻] using stoichiometry. MnCl2(aq) is an ionic compound which will have the releasing of 2 Cl⁻ ions ions in water for every molecule of MnCl2 that dissolves.
MnCl2(s) --> Mn+(aq) + 2 Cl⁻(aq)
[Cl⁻] = 0.68 mol MnCl2/1L × 2 mol Cl⁻ / 1 mol MnCl2 = 1.4 M
The answer to this question is [Cl⁻] = 1.4 M
Density = mass/volume
Since at STP, one mole of any gas occupies 22.4 liters, therefore, the volume is equal.
So, we will arrange based on mass.
From the periodic table:
mass of carbon = 12 grams
mass of calcium = 40 grams
mass of chlorine = 35.5 grams
mass of copper = 63.5 grams
Based on this:
copper has the highest density.
For better representation, let me rewrite the electronic configuration:
<span>1s</span>²<span>2s</span>²<span>2p</span>⁶<span>3s</span>²<span>3p</span>⁶<span>4s</span>²<span>3d</span>⁴
The exponents represent the number of electrons in the designated subshell. Thus, the total number of electrons are:
# of electrons = 2+2+6+2+6+2+4 = 24
Assuming this is in neutral state, the element with an atomic number of 24 is Chromium. Thus, the answer is Cr.
