It's 18 (the same as the number of protons:)
<u>Answer:</u> The mass of calcium chloride present in given amount of solution is 87.5 g
<u>Explanation:</u>
We are given:
Mass of solution = 277.8 grams
Also, 31.5 % (m/m) of calcium chloride in water. This means that 31.5 g of calcium chloride is present in 100 g of solution.
To calculate the mass of calcium chloride in the given amount of solution, we use unitary method:
in 100 g of solution, the mass of calcium chloride present is 31.5 g
So, 277.8 g of solution, the mass of calcium chloride present is
Hence, the mass of calcium chloride present in given amount of solution is 87.5 g
Here we have to get the
of the reaction at 520 K temperature.
The
of the reaction is 1.705 atm
We know the relation between
and
is
, where
= The equilibrium constant of the reaction in terms of partial pressure,
= The equilibrium constant of the reaction in terms of concentration and N = number of moles of gaseous products - Number of moles of gaseous reactants.
Now in this reaction, PCl₃ + Cl₂ ⇄ PCl₅
Thus number of moles of gaseous product is 1, and number of moles of gaseous reactants are 2. Thus N = |1 - 2| = 1 mole
The given value of
is 4.0×10⁻²
The molar gas constant, R = 0.082 L. Atm. mol⁻¹. K⁻¹ and temperature, T = 520 K.
On plugging the values in the equation we get,

Or,
= 1.705 atm
Thus, the
of the reaction is 1.705 atm
C I think it’s C I’m semi guessing