Suppose you wanted to produce an aqueous solution of = 8.65 by dissolving the following salt KNO2. At what molarity would you use?
To determine the molarity of a solution, you need to know the amount of solute (in moles) and the volume of the solvent (in liters). In this case, you want to produce an aqueous solution of KNO2 with a concentration of 8.65 M.
To calculate the molarity, you need to know the molar mass of KNO2. The molar mass of KNO2 is 85.11 g/mol.
Step 1: Determine the mass of KNO2 needed for the desired molarity.
Molarity (M) = moles of solute / liters of solution
moles of solute = Molarity (M) x liters of solution
Let's assume you want to make 1 liter (L) of the solution.
moles of solute = 8.65 M x 1 L = 8.65 moles
Step 2: Calculate the mass of KNO2 needed.
mass of KNO2 = moles of solute x molar mass of KNO2
mass of KNO2 = 8.65 moles x 85.11 g/mol = 741.4515 g
Therefore, to produce an aqueous solution of KNO2 with a concentration of 8.65 M, you would need to dissolve 741.4515 grams of KNO2 in 1 liter of water.
To determine the molarity of a solution, we need to know how many moles of solute are dissolved in a given volume of solution.
In this case, we want to produce an aqueous solution of KNO2 with a concentration of 8.65 M.
To calculate the molarity, we need to know the formula mass or molar mass of KNO2, which can be found by summing the atomic masses of each element in the compound:
K (potassium) = 39.10 g/mol
N (nitrogen) = 14.01 g/mol
O (oxygen) = 16.00 g/mol
The molar mass of KNO2 is:
39.10 g/mol + 14.01 g/mol + (2 x 16.00 g/mol) = 85.11 g/mol
Now, we know that the molarity (M) is defined as moles of solute divided by liters of solution. Rearranging this equation, we get:
moles of solute = Molarity x volume of solution (in L)
For our solution, we are given the concentration (M) as 8.65 M. So, the number of moles of KNO2 we need to dissolve can be calculated as follows:
moles of KNO2 = 8.65 M x volume of solution (in L)
Suppose you want to make a 1 L solution of KNO2. Then, the number of moles of KNO2 you would need to dissolve is:
moles of KNO2 = 8.65 M x 1 L = 8.65 moles
Therefore, to produce an aqueous solution of KNO2 with a concentration of 8.65 M, you would need to dissolve 8.65 moles of KNO2 in 1 liter of water.
Suppose you wanted to produce an aqueous solution of = 8.65 WHAT by dissolving the following salt KNO2. At what molarity would you use?
I assume the desired pH is 8.65 although you did not label it, as DrBob pointed out.
Ka = [H+][NO2-] / [HNO2]
[H+] = antilog(-8.65)=2.24x10^-9 (a basic solution)
[OH-] = Kw / [H+]
[OH-] = (1x10^-14)/(2.24x10^-9) = 4.47x10^(-6)
Ka = [H+][NO2-] / [HNO2] = 4.5x10^-4 (looked up)
Kb = Kw / Ka = (1x10^-14) / (4.5x10^-4) = 2.22x10^-11
The basic solution is formed by the hydrolysis of NO2-. The equilibrium constant is the same as the Kb:
NO2-(aq) + H2O <=> HNO2 + OH-(aq)
Kb = [HNO2][OH-] / [NO2-]
assuming [HNO2]=[OH-],
2.22x10^-11 = [4.47x10^(-6)][4.47x10^(-6)] / {[NO2-]-[4.47x10^(-6)]} or.
2.22x10^-11 = [4.47x10^(-6)][4.47x10^(-6)] / [NO2-], since 4.47x10^(-6) is very small compared to [NO2-].
Solve for [NO2-] which is the same as the concentration of NaNO2.