How many grams are KBr are needed to make a saturated solution in 100g of water at 30c
1 answer:
Explanation:
To calculate that you need to know the value of the Kps (constant of solubility) at 30°C of KBr in water.
<u>When the product of the concentrations of both ions (Br- and K+) equals the Kps, the solution is saturated. </u>
Given the disociation of the salt in water:
The concentration of both ions are equal (1:1 ratio) and the same as the concentration of KBr added.
The Kps:
[KBr] are <u>moles of the salt per litre of water</u>
Assuming a density of water of 1 g/cm3, 100 g are 0.1 litre
To calculate the mass:
where M is the molecular weight of the salt.
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Answer:
1.65 L
Explanation:
The equation for the reaction is given as:
A + B ⇄ C
where;
numbers of moles = 0.386 mol C (g)
Volume = 7.29 L
Molar concentration of C =
= 0.053 M
A + B ⇄ C
Initial 0 0 0.530
Change +x +x - x
Equilibrium x x (0.0530 - x)
where
K is given as ; 78.2 atm-1.
So, we have:
Using quadratic formula;
where; a = 78.2 ; b = 1 ; c= - 0.0530
= or
= or
= 0.0204 or -0.0332
Going by the positive value; we have:
x = 0.0204
[A] = 0.0204
[B] = 0.0204
[C] = 0.0530 - x
= 0.0530 - 0.0204
= 0.0326
Total number of moles at equilibrium = 0.0204 + 0.0204 + 0.0326
= 0.0734
Finally, we can calculate the volume of the cylinder at equilibrium using the ideal gas; PV =nRT
if we make V the subject of the formula; we have:
where;
P (pressure) = 1 atm
n (number of moles) = 0.0734 mole
R (rate constant) = 0.0821 L-atm/mol-K
T = 273.15 K (fixed constant temperature )
V (volume) = ???
V = 1.64604
V ≅ 1.65 L