The greatest source of radiation is radon gas
We are given that the concentration of NaOH is 0.0003 M and are asked to calculate the pH
We know that NaOH dissociates by the following reaction:
NaOH → Na⁺ + OH⁻
Which means that one mole of NaOH produces one mole of OH⁻ ion, which is what we care about since the pH is affected only by the concentration of H⁺ and OH⁻ ions
Now that we know that one mole of NaOH produces one mole of OH⁻, 0.0003M NaOH will produce 0.0003M OH⁻
Concentration of OH⁻ (also written as [OH⁻]) = 3 * 10⁻⁴
<u>pOH of the solution:</u>
pOH = -log[OH⁻] = -log(3 * 10⁻⁴)
pOH = -0.477 + 4
pOH = 3.523
<u>pH of the solution:</u>
We know that the sum of pH and pOH of a solution is 14
pH + pOH = 14
pH + 3.523 = 14 [subtracting 3.523 from both sides]
pH = 10.477
The molar mass of B(NO₃)₃ - Boron nitrate : 196.822 g/mol
<h3>Further explanation</h3>
In stochiometry therein includes
<em>Relative atomic mass (Ar) and relative molecular mass / molar mass (M) </em>
So the molar mass of a compound is given by the sum of the relative atomic mass of Ar
M AxBy = (x.Ar A + y. Ar B)
The molar mass of B(NO₃)₃ - Boron nitrate :
M B(NO₃)₃ = Ar B + 3. Ar N + 9.Ar O
M B(NO₃)₃ = 10.811 + 3. 14,0067 + 9. 15,999
M B(NO₃)₃ = 196.822 g/mol
1 mol of Br = 79.9 g
15.7 g / 79.9 g = 0.196 moles of atoms
