0.125g of sodium dichromate is to be reacted wtih 0.025M potassium iodide. How many mLs of the potassium iodide solution will be needed. (Use your balanced equations above.)
Sorry the equation is:
Cr2O7^2- + I- ---> Cr^3+ + IO3^-
(dont sure the balanced equation)
the balance equation is the overall net ionic equation. so use that to obtain the mole ratio between Na2Cr2O7 and KI.
calculate the mole of sodium dichromate by m/Mr where m is 0.125g and Mr is molar mass. Then determine the mole of KI with using the mole of sodium dichromate and the mole ratio. once you have the mole for KI, calculate the volume using M = n/V where M is molarity, n is the mole and V is the volume. You might need to consider unit conversion.
hope that helps
To determine the volume of potassium iodide solution needed, we need to start by balancing the chemical equation for the reaction between sodium dichromate (Na2Cr2O7) and potassium iodide (KI).
The balanced chemical equation is as follows:
Na2Cr2O7 + 14KI + 8H2SO4 → 2Cr2(SO4)3 + 7I2 + 2Na2SO4 + 8H2O
From the balanced equation, we can see that 14 moles of potassium iodide (KI) react with 1 mole of sodium dichromate (Na2Cr2O7).
Now, let's convert the given amount of sodium dichromate (0.125g) to moles:
Molar mass of Na2Cr2O7 = 2(22.99) + 2(51.99) + 7(16) = 294.18 g/mol
Moles of Na2Cr2O7 = Mass / Molar mass = 0.125g / 294.18 g/mol
Next, let's calculate the number of moles of potassium iodide (KI) needed:
Moles of KI = Moles of Na2Cr2O7 / (1 mole Na2Cr2O7: 14 moles KI)
Now we have the number of moles of potassium iodide (KI) needed.
To find the volume of the potassium iodide solution, we will use the given concentration of 0.025M (moles per liter). Since we know the number of moles needed, we can use the following formula:
Volume (in liters) = Moles / Concentration
Volume (in mL) = (Volume in liters) * 1000
Let's plug in the values and calculate:
Volume (in liters) = Moles of KI / Concentration of KI
Volume (in mL) = (Moles of KI / Concentration of KI) * 1000
Remember to ensure that the units are consistent (mL for volume and M for concentration) before performing the calculations.
By using the balanced equation and the given information, you should now be able to calculate the volume of the potassium iodide solution needed in mL.