What mass of Cr(OH)3 would be produced if 500ml of 0.250M KOH were added to a solution of CrCl3. I need to understand how to set this up, not just get the answer. I have the balanced equation figured out.
Here is an example. Just follow the steps. Mole of the starting material is M x L.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine the mass of Cr(OH)3 produced, you need to follow a few steps:
1. Write the balanced chemical equation for the reaction:
3 KOH + CrCl3 → Cr(OH)3 + 3 KCl
2. Determine the mole ratio between KOH and Cr(OH)3 from the balanced equation:
From the equation, we can see that 3 moles of KOH react to form 1 mole of Cr(OH)3.
3. Convert the volume of the KOH solution from milliliters (ml) to liters (L):
500 ml = 500/1000 L = 0.500 L
4. Calculate the number of moles of KOH using its molarity and volume:
Moles of KOH = Molarity of KOH × Volume of KOH solution (in L)
Moles of KOH = 0.250 mol/L × 0.500 L = 0.125 mol
5. Use the mole ratio to determine the number of moles of Cr(OH)3 produced:
Since the mole ratio is 3:1 between KOH and Cr(OH)3, we can say that:
Moles of Cr(OH)3 = (0.125 mol KOH) × (1 mol Cr(OH)3 / 3 mol KOH)
Moles of Cr(OH)3 = 0.0417 mol
6. Convert the moles of Cr(OH)3 to grams using its molar mass:
The molar mass of Cr(OH)3 is calculated by adding up the atomic masses of Cr, O, and H, from the periodic table:
Molar mass of Cr = 52.0 g/mol
Molar mass of O = 16.0 g/mol
Molar mass of H = 1.0 g/mol
Molar mass of Cr(OH)3 = (52.0 g/mol) + (3 × 16.0 g/mol) + (3 × 1.0 g/mol) = 102.0 g/mol
Mass of Cr(OH)3 = Moles of Cr(OH)3 × Molar mass of Cr(OH)3
Mass of Cr(OH)3 = 0.0417 mol × 102.0 g/mol = 4.25 g
Therefore, 4.25 grams of Cr(OH)3 would be produced when 500 ml of 0.250 M KOH is added to a solution of CrCl3.