8.00g of NaOH are dissolved in water to make 4.00 of solution. What is the concentration of hydronium ions, , in this solution?
To find the concentration of hydronium ions (H3O+) in a solution of NaOH, we need to understand that NaOH is a strong base that completely dissociates in water to form sodium ions (Na+) and hydroxide ions (OH-).
Given that 8.00g of NaOH is dissolved in water to make 4.00L of solution, we can start by calculating the molarity (M) of the NaOH solution using the formula:
M = (moles of solute) / (volume of solution in liters)
1. First, we need to determine the number of moles of NaOH:
a. The molar mass of NaOH is calculated by adding the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). The atomic masses are: Na = 22.99 g/mol, O = 16.00 g/mol, and H = 1.01 g/mol.
molar mass of NaOH = 22.99 g/mol + 16.00 g/mol + 1.01 g/mol = 40.00 g/mol
b. To find the number of moles, we divide the mass of NaOH by its molar mass:
moles of NaOH = (mass of NaOH) / (molar mass of NaOH)
= 8.00 g / 40.00 g/mol
= 0.20 mol
2. Next, we can calculate the molarity of the NaOH solution:
M = moles of solute / volume of solution in liters
= 0.20 mol / 4.00 L
= 0.05 M
Now, since NaOH fully dissociates in water, the concentration of hydroxide ions (OH-) is equal to the molarity of the NaOH solution. Therefore, the concentration of hydronium ions (H3O+) is equal to the concentration of hydroxide ions (OH-).
Hence, the concentration of hydronium ions in this solution is 0.05 M.