Arsenic trisulfide (As 2 S 3 ) occurs naturally as the orange-yellow colored mineral orpiment. As 2 S 3 is a highly insoluble substance with a Ksp value of 2.90×10 −72 . Calculate the solubility of As 2 S 3 in g/100mL. (Molar mass of As 2 S 3 = 246.04 g/mol)

Here we're going to say that Arsenic Trisulfide occurs naturally as the orange yellow colored mineral, Orbanant. Now here, Arsenic Trisulfide is a highly insoluble substance with a Ksp value of 2.90 times 10 to the negative 72. Calculate the solubility in grams per 100 milliliters. Alright. So here, we're dealing with Ksp, so we're dealing with an ionic solid. We're gonna show that it's partially soluble, so double arrows. This breaks up into 2 arsenics, each one with a charge of 3 plus, plus 3 sulfides, each one with a charge of 2 minus. We have initial change equilibrium. We ignore solids. Initially, these are 0, plus 2x, plus 3x, plus 2x, plus 3x. Ksp equals products over reactants, but it only equals the products here since they're the aqueous ones. So then this equals 2x squared times 3x cubed, which is 4x squared times 27x cubed. And that equals 108x cubed. X to the 5th, sorry, x to the 5th. And that equals our 2.90 times 10 to the negative 72. Divide both sides now by 108. So x to the 5th equals 2.685 times ten to the minus seventy 4. We're going to take the 5th root of this. So really just raising it to the 1 5th power gives us 1.9311 times 10 to the negative 15 molarity, which will be moles per liter. So moles of our substance over 1 liter. But we want this in grams for 100 ml's. So we're gonna say 1 mole. We told it weighs 246.04 grams. Right? And then we're gonna say here, 0.1 liters is a 100 milliliters. So right there, we're gonna have grams per 100 milliliters. So it's gonna give me 4 0.75 times 10 to the minus 16 grams per 100 ml, per grams per milliliters at the end actually. So this is the answer we can write. So we can write it in this form, or you could say it as 4.75 times 10 to the negative 14 grams per 100 milliliters. This is also an acceptable answer for this particular question.

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6. Chemical Equilibrium

Solubilty Product Constant

Analytical Chemistry

6. Chemical Equilibrium

Solubilty Product Constant

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Multiple Choice

Arsenic trisulfide (As₂S₃) occurs naturally as the orange-yellow colored mineral orpiment. As₂S₃ is a highly insoluble substance with a Ksp value of 2.90×10⁻⁷². Calculate the solubility of As₂S₃ in g/100mL. (Molar mass of As₂S₃ = 246.04 g/mol)

2.12×10⁻¹⁷ g/100 mL

1.87×10⁻¹³ g/100 mL

6.25×10⁻¹⁵ g/100 mL

4.75×10⁻¹⁴ g/100 mL

Previous problem

Verified step by step guidance

First, write the dissolution equation for arsenic trisulfide (As2S3) in water: As2S3(s) ⇌ 2As^3+(aq) + 3S^2−(aq).

Next, express the solubility product constant (Ksp) in terms of the concentrations of the ions: Ksp = [As^3+]^2[S^2−]^3.

Let the solubility of As2S3 be 's' mol/L. Then, [As^3+] = 2s and [S^2−] = 3s. Substitute these into the Ksp expression: Ksp = (2s)^2(3s)^3.

Simplify the expression: Ksp = 4s^2 * 27s^3 = 108s^5. Set this equal to the given Ksp value: 108s^5 = 2.90×10^−72.

Solve for 's' to find the molar solubility, then convert this to grams per 100 mL using the molar mass of As2S3 (246.04 g/mol) and the conversion factor (1 L = 1000 mL).