A sample of 8 grams of NaOH is dissolved into
599 mL of aqueous 0.250 M NaOH (assume
no volume change). This solution is then
poured into 1.68 gallons of water. (You may
assume that the two volumes can be added.)
What is the concentration of NaOH in the
final solution?
Answer in units of M
To find the concentration of NaOH in the final solution, we need to first calculate the amount of NaOH in moles in the initial solution, and then determine the total volume of the final solution. With these two values, we can calculate the concentration.
1. Calculate the moles of NaOH in the initial solution:
Given mass of NaOH = 8 grams
Molar mass of NaOH = 22.99 g/mol (Na) + 16 g/mol (O) + 1.01 g/mol (H) = 39.99 g/mol
Moles of NaOH = Mass of NaOH / Molar mass of NaOH = 8 g / 39.99 g/mol
2. Determine the total volume of the final solution:
Volume of aqueous NaOH solution = 599 mL = 0.599 L
Volume of water = 1.68 gallons
1 gallon = 3.78541 L (conversion factor)
Volume of water = 1.68 gallons * 3.78541 L/gallon
Total volume of final solution = Volume of aqueous NaOH solution + Volume of water
3. Calculate the concentration of NaOH in the final solution:
Concentration = Moles of NaOH / Volume of final solution
Now we can substitute the values and calculate the concentration in units of M.
Note: Make sure to convert the units consistently throughout the calculation. If necessary, convert gallons to liters or liters to gallons before performing any calculations.