A solution is prepared by mixing 8 mL of .2 M Fe(NO3)3, 10mL of .001 M NaSCN, and 7 mL of .1 M HNO3
a. calculate the concentration of Fe3+ in the solution
b. calculate the SCN- in the solution
Do you want the concn BEFORE or AFTER a reaction.
I assume before.
Fe^+3 = 0.2M to start. How much has it been diluted? From 8 mL to a total of 25 mL (8 + 10 + 7 = 25 mL).
Fe^+3 = 0.2M x (8/25) = ??M
SCN = 0.001M x (10/25) = ??M
To calculate the concentration of Fe3+ and SCN- in the solution, we need to use the concept of stoichiometry and the balanced chemical equation for the reaction between Fe3+ and SCN-.
The balanced chemical equation for the reaction between Fe3+ and SCN- is:
Fe3+ + SCN- → FeSCN2+
From the balanced equation, we can see that 1 mole of Fe3+ reacts with 1 mole of SCN- to form 1 mole of FeSCN2+.
a. To calculate the concentration of Fe3+ in the solution:
First, we need to determine the number of moles of Fe3+ in the solution.
Number of moles Fe3+ = Volume of Fe(NO3)3 (in liters) * Concentration of Fe(NO3)3 (in moles per liter)
= 8 mL * 0.2 mol/L * (1 L / 1000 mL)
= 0.0016 moles
Since Fe(NO3)3 dissociates to give 1 mole of Fe3+ ions in the solution, the concentration of Fe3+ can be calculated using the formula:
Concentration of Fe3+ = Number of moles Fe3+ / Total volume of the solution (in liters)
= 0.0016 moles / (8 mL + 10 mL + 7 mL) * (1 L / 1000 mL)
= 0.0016 moles / 0.025 L
= 0.064 mol/L
Therefore, the concentration of Fe3+ in the solution is 0.064 M.
b. To calculate the concentration of SCN- in the solution:
First, we need to determine the number of moles of SCN- in the solution.
Number of moles SCN- = Volume of NaSCN (in liters) * Concentration of NaSCN (in moles per liter)
= 10 mL * 0.001 mol/L * (1 L / 1000 mL)
= 0.00001 moles
Since NaSCN dissociates to give 1 mole of SCN- ions in the solution, the concentration of SCN- can be calculated using the formula:
Concentration of SCN- = Number of moles SCN- / Total volume of the solution (in liters)
= 0.00001 moles / (8 mL + 10 mL + 7 mL) * (1 L / 1000 mL)
= 0.00001 moles / 0.025 L
= 0.0004 mol/L
Therefore, the concentration of SCN- in the solution is 0.0004 M.