Potassium tetraoxalate has the formula H2C2O4.KHC2O4.xH2O. 1.923 g of the above
compound was neutralized by 22.7 mL of 1.000 M NaOH using phenolphthalein as the
indicator. Calculate the value of x in the formula.
To calculate the value of x in the formula of potassium tetraoxalate (H2C2O4.KHC2O4.xH2O), we need to determine the number of moles of the compound and the number of moles of NaOH used to neutralize it.
Let's break down the steps to find the answer:
Step 1: Calculate the number of moles of NaOH used.
The concentration of NaOH is given as 1.000 M (moles per liter), and the volume used is 22.7 mL (converted to liters, 22.7/1000 = 0.0227 L). Using the formula: moles = concentration x volume, we can calculate the number of moles of NaOH:
moles NaOH = 1.000 M x 0.0227 L
Step 2: Convert the weight of the compound to moles.
We are given that 1.923 g of the compound was used. To convert this to moles, we need to determine the molar mass of the compound. The molar mass of potassium tetraoxalate (H2C2O4.KHC2O4.xH2O) is the sum of the molar masses of its constituent elements.
Molar mass of H2C2O4 = (2 x 1.008) + (2 x 12.01) + (4 x 16.00) = 88.04 g/mol
Molar mass of KHC2O4 = (39.10) + (1 x 1.008) + (2 x 12.01) + (4 x 16.00) = 128.14 g/mol
Molar mass of H2O = (2 x 1.008) + (1 x 16.00) = 18.02 g/mol
By adding these molar masses, we can calculate the total molar mass of the compound:
Total molar mass = (88.04 + 128.14 + 18.02x) g/mol
Now, we can convert the mass of the compound to moles:
moles compound = 1.923 g / Total molar mass
Step 3: Determine the value of x.
From the equation H2C2O4.KHC2O4.xH2O + NaOH, we can see that for every mole of NaOH, x moles of H2O are produced. Therefore, the number of moles of NaOH used should be equal to the number of moles of H2O produced:
moles NaOH = x moles H2O
Now, we can set up an equation based on the moles calculated in Steps 1 and 2:
1.000 M x 0.0227 L = x moles H2O
Finally, solve for x:
x = (1.000 M x 0.0227 L) / moles compound
Plug in the values determined in Steps 1 and 2 to calculate the value of x.