Calculate the molar solubility of MX2, if the Ksp=3.3x10^-8
i already asked this but im confused about one of the steps.
Ksp = (x)(2x)^2 = 4x^3 = 3.3X10^-8
x = solubility = 0.00202M.
but i don't understand do i substitute the x in 4x^3 3.3X10^-8 and then divide by 3.3X10^-8. or am i wrong?
i tried solving it on my own but im confused by the steps and when i calculate i don't end up with 0.00202. please help!
4x^3 = 3.3E-8
x^3 = (3.3E-8/4) = 8.25E-9
x= cube root(8.25E-9) = 0.00202 M
thanks! it looks like i was calculating the cube and not the cube root!
To find the molar solubility (x) of MX2 using the given Ksp value, you need to set up an equation based on the Ksp expression and then solve for x.
The Ksp expression for MX2 is:
Ksp = [M][X]^2
where [M] represents the molar concentration of M ion and [X] represents the molar concentration of X ion.
For MX2, since the formula shows that 1 mole of M combines with 2 moles of X, you can write the expression as:
Ksp = (x)(2x)^2
Simplifying, you get:
Ksp = 4x^3
Now, to find the value of x, you need to rearrange the equation:
4x^3 = Ksp
In this case, the given Ksp value is 3.3 x 10^-8. So, substitute this value into the equation:
4x^3 = 3.3 x 10^-8
Next, to solve for x, divide both sides of the equation by 4:
x^3 = (3.3 x 10^-8) / 4
x^3 = 8.25 x 10^-9
Finally, take the cube root of both sides to solve for x:
x = (8.25 x 10^-9)^(1/3)
Evaluating this expression will give you the molar solubility, x, of MX2.