A sample of 7.83 grams of NaOH is dissolved
into 620 mL of aqueous 0.250 M NaOH (as-
sume no volume change). This solution is
then poured into 1.67 gallons of water. (You
may assume that the two volumes can be
added.) What is the concentration of NaOH
in the final solution?
how much NaOH do you have in moles?
7.83/40 + .620*.250
concentration: molesNaOH/2liters
To find the concentration of NaOH in the final solution, we need to calculate the moles of NaOH initially and the volume of the final solution.
Let's start by calculating the moles of NaOH from the given mass and molar mass:
1. Calculate the moles of NaOH:
moles = mass / molar mass
moles = 7.83 g / 40.0 g/mol (molar mass of NaOH)
moles = 0.196 mol
Next, let's find the volume of the final solution in liters:
2. Convert gallons to liters:
1 gallon = 3.78541 liters
1.67 gallons = 1.67 * 3.78541 liters = 6.32319 liters
Now, we can calculate the final concentration of NaOH:
3. Use the formula for concentration:
concentration = moles / volume
concentration = 0.196 mol / 6.32319 L
concentration ≈ 0.031 M
Therefore, the concentration of NaOH in the final solution is approximately 0.031 M (molar).