A solution of HClO4 was standardized by dissolving 0.3745 g of primary standard grade HgO in a solution of KBr.
The liberated OH- required 37.99 mL of the acid to be neutralized. Find the molarity(M) of HClO4.
The given balanced chemical equation is:
HgO + 4Br- + H20 ===> HgBr4^2- + 2OH-
mols HgO = grams/molar mass = ?
Using the cofficients in the balanced equation, convert mols HgO to mols OH^-
then convert that to mols HClO4.
Finally, M HClO4 = mols HClO4/L HClO4
10.4
To find the molarity (M) of HClO4, we need to use the balanced chemical equation and the data given.
Step 1: Calculate the number of moles of HgO used:
Given mass of HgO = 0.3745 g
Molar mass of HgO = 216.59 g/mol
Number of moles of HgO = mass / molar mass = 0.3745 g / 216.59 g/mol = 0.001729 mol
Step 2: Calculate the number of moles of OH- required for neutralization:
Volume of HClO4 = 37.99 mL = 37.99 cm^3
1 mole of OH- reacts with 1 mole of HClO4 (from the balanced equation)
Number of moles of OH- = Volume of HClO4 (in L) * Molarity of HClO4
Step 3: Calculate the molarity of HClO4:
Molarity of HClO4 = Number of moles of OH- / Volume of HClO4 (in L)
Let's calculate the molarity of HClO4:
Step 2: Convert the volume of HClO4 to liters:
Volume of HClO4 = 37.99 mL = 37.99 cm^3 = 37.99 / 1000 L = 0.03799 L
Step 3: Calculate the number of moles of OH-:
Number of moles of OH- = Volume of HClO4 * Molarity of HClO4
0.001729 mol = 0.03799 L * Molarity of HClO4
Molarity of HClO4 = 0.001729 mol / 0.03799 L
Molarity of HClO4 = 0.0455 M
Therefore, the molarity (M) of HClO4 is 0.0455 M.
To find the molarity (M) of HClO4, we can use the stoichiometry of the balanced chemical equation and the given data.
Step 1: Calculate the moles of HgO
The molar mass of HgO is 216.59 g/mol.
moles of HgO = mass of HgO / molar mass of HgO
moles of HgO = 0.3745 g / 216.59 g/mol
Step 2: Determine the moles of OH-
From the balanced chemical equation, we can see that 1 mole of HgO reacts with 2 moles of OH-.
moles of OH- = (moles of HgO) x (2 moles of OH-/1 mole of HgO)
Step 3: Calculate the molarity of HClO4
Molarity = (moles of HClO4) / (volume of HClO4 solution in liters)
Molarity = (moles of HClO4) / (37.99 mL converted to L)
Now let's calculate the values:
Step 1: moles of HgO
moles of HgO = 0.3745 g / 216.59 g/mol ≈ 0.001728 mol
Step 2: moles of OH-
moles of OH- = (0.001728 mol of HgO) x (2 mol of OH-/1 mol of HgO) ≈ 0.003456 mol
Step 3: Molarity of HClO4
Molarity = (moles of HClO4) / (37.99 mL converted to L)
Molarity = (0.003456 mol) / (37.99 mL / 1000 mL/L) ≈ 0.09097 M
Therefore, the molarity of HClO4 is approximately 0.09097 M.